Underhood Service, February 2014 by Babcox Media

■ ASE A1 Test Prep ■ DiagnosticDilemma: Stalling ■ DiagnosticPathfinder: Cold Treatment A

MAGAZINE

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Publication

CONTENTS 16

2.14 Volume 19, No. 2

Drivetrain Diagnostics

Diagnostic Dilemmas

Diagnostic Pathfinder

Solving Electronic Control Problems

Intermittent Stall

Cold Weather Diagnostics

Troubleshooting an automatic transmission problem can be very profitable. Many repairs do not require that the transmission be removed from the vehicle, so some problems can be solved with just a scan tool.

Diagnosing intermittent stalling complaints is a challenging experience for any diagnostic technician. Gary Goms shows us one case where it could be a problem with communications.

John Forro discusses an interesting no-start problem where the issue was influenced by the weather and trying to diagnosis the problem inside a warm shop was an issue.

Publisher Jim Merle email: jmerle@babcox.com 330-670-1234, ext. 280

Managing Editor Chris Crowell email: ccrowell@babcox.com 330-670-1234, ext. 268

Editor Andrew Markel email: amarkel@babcox.com 330-670-1234, ext. 296

Graphic Designer Dan Brennan email: dbrennan@babcox.com 330-670-1234, ext. 283

Contributing Writers Gary Goms, Scott “Gonzo” Weaver, Bob Dowie and John Forro Ad Services (Materials) Cindy Ott email: cott@babcox.com 330-670-1234, ext. 209 Technical Editor Larry Carley

2 February 2014 | UnderhoodService.com

Circulation Manager Pat Robinson email: probinson@babcox.com 330-670-1234, ext. 276 Subscription Services Maryellen Smith email: msmith@babcox.com 330-670-1234, ext. 288

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DEPARTMENTS

Columns

6 Directions 8 Gonzo’s Toolbox 10 Aftermarket Update 20 ASE A1 Prep: Head

Publication

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Gasket

22 Emissions: Platinum

Problems

26 Air Filters & Fuel Trims 46 Tech Tips 50 SHOP: New Products 53 Classifieds 52 RAPID RESPONSE 56 Emissions Update: EGR

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Valves and Air Pumps EDITORIAL ADVISORY BOARD Brent Crago, owner Top Tech Automotive Cleveland, Tennessee

Anthony Hurst, owner Auto Diagnostics Ephrata, Pennsylvania

Tom Palermo, general manager Preferred Automotive Specialists Jenkintown, Pennsylvania

Paul Stock, owner Stock’s Underhood Specialists Belleville, Illinois

Albert Duebber, owner Duebber’s Auto Service Cincinnati, Ohio

Roger Kwapich, owner Smitty’s Automotive Toledo, Ohio

Van Pedigo, owner Richfield Automotive Center Richfield, Ohio

Michael Warner, owner Suburban Wrench Pennington, New Jersey

Marvin Greenlee, owner Meade & Greenlee Inc. Salem, Oregon

Rick O’Brien, technician Coachworks Portland, Maine

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UNDERHOOD SERVICE (ISSN 1079-6177) February 2014, Volume 19, Number 2): Published monthly by Babcox, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Phone (330) 670-1234, FAX (330) 670-0874. Periodical postage paid at Akron, OH 44333 and additional mailing offices. POSTMASTER: Please send address changes to UNDERHOOD SERVICE, 3550 Embassy Parkway Akron, OH 44333. UNDERHOOD SERVICE is a trademark of Babcox Media, Inc. registered with the U.S. Patent and Trademark Office. All rights reserved. A limited number of complimentary subscriptions are available to individuals who meet the qualification requirements. Call (330) 670-1234, Ext. 288, to speak to a subscription services representative or FAX us at (330) 670-5335. Paid Subscriptions are available for non-qualified subscribers at the following rates: U.S.: $69 for one year. Canada: $89 for one year. Canadian rates include GST. Ohio residents add current county sales tax. Other foreign rates/via air mail: $129 for one year. Payable in advance in U.S. funds. Mail payment to UNDERHOOD SERVICE, P.O. Box 75692, Cleveland, OH 44101-4755. VISA, MasterCard or American Express accepted.

4 February 2014 | UnderhoodService.com

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» Directions

By Andrew Markel | EDITOR

Relax - R1234yf is not the end of the world.

attended the Mobile Air Conditioning Society’s 2014 Training Event and Trade Show in New Orleans last month. The main topic of discussion was R1234yf, or “twelve-thirty-four” in A/C lingo.

There has been a lot of hype about the changeover to this refrigerant. Don’t panic. The reality is that it is not the “air conditioning apocalypse” some are predicting. Instead, it will be a slow adoption the next three to five years. R134a will not be phased out, but it will be regulated and taxed heavily. The reason behind the change is the length of time refrigerants can linger in the upper atmosphere. R134a may take up to 10 years to breakdown into a non-greenhouse gas. Twenty-five years ago, this was seen as considerable improvement over the 100-year-plus lifespan of R12. But R1234yf is a further advancement over R134a, as it takes only three to four years to break down in the upper atmosphere.

You have Time Relax, now is the time to train and tool up. R1234yf is not required until the 2017 model year. Some models are being switched over now so automakers can receive green-

February 2014 | UnderhoodService.com

house gas credits until the 2016 model year. Even with the quick breakdown of R1234yf, you will still have to purchase a new machine to recover and recycle the new refrigerant. You will also need to understand the new oil compatablity issues with the R1234yf and what happens when refrigerants mix. The one investment you should make now is a refrigerant identifier tool.

Vehicles with R1234yf Cadillac XTS (2013, 2014) Chevrolet Spark EV (2014) Chrysler 300 (2014) Dodge Challenger (2014) Dodge Charger (2014) Honda Fit EV (2013, 2014) Jeep Cherokee (2014) Range Rover (2014) Range Rover Sport (2014) The performance of R1234yf is very similar to R134a. There will be no major changes to system components. There are changes to the H-block, hoses and the programming in the module that controls the HVAC system. There are reports of some car manufacturers not wanting to use R1234yf due to the flammability issue. Ignore the stories about increased flammabil-

ity. They will comply sooner rather than later. The flammability of R1234yf is no worse than anything else inside the interior, including the plastics used in the interior. Some say the posturing is to delay the changeover until the current market prices for R1234yf go down. Current prices for the new refrigerant are around $120 a pound and typically can only be found at new car dealerships. The price will come down significantly in the next few years as plants around the world ramp up production. If you were working in 1994 at a shop when the first R134a cars hit the aftermarket, charging $65 for a pound of R134a or R12 was not unusual. Back then, some shop owners made the mistake of building stockpiles of refrigerant at the inflated prices. The main issue is not with the chemical structure or politics behind R1234yf, it is how it will be serviced. There will be issues with contamination as systems are serviced. Some oils will not be compatible. You may get a vehicle in your shop in the near future that might have a blend of refrigerants. But these are issues that can be resolved with training and tools. ■

» Gonzo’sToolbox By Scott “Gonzo” Weaver

Lessons from a day out of my comfort zone

onday through Friday it’s the same routine: My average day begins with the usual commute to work, coffee and the turn of my key to the front door. I unlock the overheads and do any morning paper work I have waiting. For the most part, every working day has the same general routine, one day to the next, each month and each year. Being under the dash or hood of the modern car is my comfort zone, but it doesn’t hurt to get out of my comfort zone. Like a lot of people, that day-in, day-out grind can give me a snapping attitude. I could use a reminder now and then that what I do for a living ain’t all that bad, and I owe my customers a great deal of gratitude for their patronage and for putting up with this snarly old mechanic. You can take those average days in your own little comfort zone for granted and forget there is more to what makes the world go around besides the next car you’re working on. Sometimes it might take a little nudge from an outside source to get you to realize it. Recently, I took a few days off and ventured out on a road trip with my wife to one of her “comfort zones.” Ok, I was “volun-told” by my wife, but I didn’t complain too much. It was three days of little old ladies, sewing machines and quilts. Goodbye, comfort zone. I didn’t have any tools, scanners or hoods to hide under. Well over a hundred women with scissors, big fancy (expensive) sewing machines and colorful fabric were on hand. There weren’t many husbands at the retreat, and the hotel staff had its hands full, so they kept me busy as their bell boy (minus the quirky cap of course), carrying their machines from the parking lot to their classrooms. If you ask my wife she’ll tell you, “Oh, he fusses, but he loves every minute of it.” I wasn’t concerned about what she was telling them anyway, I just pulled my ball cap down a bit tighter and asked the next lady with a sewing machine, “Where do ya’ want this one moved to, ma’am?”

February 2014 | UnderhoodService.com

This whole experience made me think of what it is like for a non-car person to enter an automotive repair shop. The actual interaction with the service writer or mechanic can be intimidating. For me, a weekend with the wife surrounded by thread and quilts was, believe it or not, intimidating. Especially when one of them asks me something about their sewing machine or quilting. Look, I know what a PCM and a ball joint are, but I haven’t a clue about flying geese or halfsquare triangles. And these women loved to rub it in. Uncomfortable? Yes. Intimidating? Well, let’s put it this way: When I was stuck in front of a sewing machine and clued in on which buttons to push to make it sew, they got quite a chuckle out of watching some big, burly guy fumble around with a sharp needle and try to hold a thin piece of fabric with his nubby fingers. Sooner or later one of them would push me aside and say, “Here, let me show ya’ how to do this.” I’d like to think I can learn how to operate any sort of machinery, even one of these ultra-expensive sewing machines, but these women are in a league of their own. They made it look so easy, and I can’t even figure out how to sew a straight line. I certainly can take some lessons from the quilting retreat. The women did their best to make me feel comfortable. The real heart of the intimidation was trying to hold a conversation with them and not having a clue what they were talking about, or what they were doing. I’ve got to keep this in mind when I’m back at the shop. I should try harder not to be so intimidating, work to keep things on common ground, and not make it so overwhelming for the customer, especially those who are uncomfortable about a stranger they just met working on their car. I got it, ladies — thank you. Now, the other question is, can I turn some of the experience of being out of my comfort zone into my average day? I’m sure going to try. ■

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» AftermarketUpdate Brought to you by:

For free e-mail updates with the latest aftermarket news, tech tips and supplier promotions, log on to AutoCarePro.com.

Federal-Mogul ‘SmartChoice Mobile’ App Selected for North American Customer Value Leadership Award Federal-Mogul’s popular, free “SmartChoice™ Mobile” app for automotive service providers has been selected for the Frost & Sullivan North American Customer Value Leadership Award. The Frost & Sullivan award is presented annually to a company that has demonstrated excellence in implementing strategies that proactively create value for its customers. Representatives of the Federal-Mogul Vehicle Components segment received the award Jan. 14 during the Frost & Sullivan Excellence in Best Practices Awards Gala in New Orleans. The innovative SmartChoice Mobile app enables users of iPhone and Android devices to instantly access the latest Federal-Mogul parts information and technical support for virtually any passenger car or light truck, and communicate detailed inspection findings — including photos and repair estimate — directly to the vehicle owner. The app includes VIN scanning technology that can instantly capture critical vehicle information and link the user to all corresponding parts and repair information via Federal-Mogul’s www.FMe-Cat.com applications database. “Federal-Mogul has revolutionized the repair sector by provid-

February 2014 | UnderhoodService.com

ing service professionals with a tool that integrates the three basic components of the repair process: fast, accurate identification of the vehicle application; detailed information about the parts needed for the repair; and clear, concise communication with the consumer,” wrote the Frost & Sullivan Best Practices research team. The Frost & Sullivan team highlighted three key characteristics that make SmartChoice Mobile uniquely valuable for repair professionals: Ease of use (the app features a highly intuitive user interface that minimizes the number of data inputs and clicks necessary to access information); availability across multiple platforms; and the unparalleled breadth of available content and

» AftermarketUpdate live technical support. Nearly 5,500 industry professionals have downloaded the app since its introduction in late September. “SmartChoice Mobile is a central part of the growing digital ecosystem available to professional technicians who rely on any Federal-Mogul product,” said Brian Tarnacki, director, global market strategy, FederalMogul Vehicle Components segment. “The entire automotive parts and service industry depends on the continued operational efficiency and competitiveness of independent service businesses. This tool, like our many other online and in-market technical resources, is ultimately an investment in our customers’ long-term success.” The vehicle service professional can use the app’s “Send Inspection Results” feature to compose and send to the consumer a shop-branded email, complete with inspection results, repair estimate and images of the vehicle’s worn parts. This email summary also includes instantreply and callback buttons to encourage the vehicle owner to ask questions and/or authorize the repair. Technicians can also use the app to connect with an ASE-certified technical specialist at the Federal-Mogul Technical EducationCenter (F-M TEC) in St. Louis. The free Federal-Mogul SmartChoice Mobile app can be downloaded through the Apple App Store and Google Play as well as the company’s www.SmartChoiceApp.com website.

12 February 2014 | UnderhoodService.com

CARQUEST

Auto Parts Announced ‘Ten To Win’ Sweepstakes Grand Prize Winner Sammy Guinn of Guinn’s Tire & Auto in Marietta, GA., is the 2013 CARQUEST ‘Ten To Win’ Sweepstakes Grand Prize Winner. Guinn is the winner of a fully restored 1965 Ford Mustang. He took delivery of his prize Jan. 18 at the Barrett-Jackson Auction in Scottsdale, AZ. The CARQUEST Ten to Win Sweepstakes was a 10-month contest, held February 2013 to November 2013, exclusively for professional customers of CARQUEST Auto Parts stores. Each month featured a customer winning a trip to the 2014 Scottsdale Barrett-Jackson Auction and a chance to win the fully restored 1965 Ford Mustang. Grand Prize Winner Sammy Guinn is owner of Guinn’s Tire & Auto, a family-owned and operated business in the Marietta, GA., area for more than 35 years. His business is also a proud member of TECH-NET Professional Auto Service.

American Petroleum Institute’s Motor Oil Matters Program Calls For Consumers’ New Year Car-Solutions Motor Oil Matters (MOM) recently launched its “New Year’s CarSolution” Sweepstakes, a Facebook promotion to encourage car and truck owners to resolve to use high-quality motor oil in their vehicles in 2014. Those who share their resolution with MOM have a chance to win a pre-paid $100 gift card. “MOM created this sweepstakes to continue the push to educate car and truck owners in a fun, interactive way about the importance of using high-quality motor oil and its importance to their second largest investment: their vehicle,” said Kevin Ferrick, API’s Engine Oil Licensing and Certification System manager. “Proper engine maintenance, particularly regular oil changes using oils that meet specific performance standards, is pivotal to the overall health of your vehicle, especially in harsh weather like many of us are experiencing.” Consumers can enter the sweepstakes by logging on to the Motor Oil Matters Facebook page (www.facebook.com/MotorOilMatters) and posting a comment on that day’s “New Year’s Car-Solution” Sweepstakes Facebook post. Ten lucky winners will be determined through a random drawing to be held soon after the sweepstakes close.

» AftermarketUpdate xx Automakers, Aftermarket To Preserve Consumer Choice In Auto Repair The Alliance of Automobile Manufacturers (Alliance), the Association of Global Automakers (Global), the Automotive Aftermarket Industry Association (AAIA) and the Coalition for Automotive Repair Equality (CARE) have announced their collective acceptance of a national agreement to ensure consumer choice in post-warranty auto repair, decisively ending the longstanding “Right to Repair” debate within the industry.

The national agreement is based on a recent law finalized in the Commonwealth of Massachusetts (Chapter 165 of the Acts of 2013). The signed Memorandum of Understanding (MOU) extends nationwide the essential provisions for all light vehicles negotiated in the Massachusetts law; it impacts all companies and organizations that are currently members of the signatory associations. This national agreement ensures the Alliance, Global,

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14 February 2014 | UnderhoodService.com

AAIA and CARE will stand down in their fight on “Right to Repair” and work collectively to actively oppose individual state legislation while the respective groups work to implement this MOU. In the meantime, the parties agree that further state legislation is not needed and could serve to weaken the effectiveness and clarity of the MOU. “We are excited that consumers and independent repair facilities around the nation will have the same access to the information, tools and software needed to service late-model computer controlled vehicles as is required under the Massachusetts right to repair statute,” said Kathleen Schmatz, president and CEO of the Automotive Aftermarket Industry Association. “We believe that the resulting competitive repair market is a win-win for car companies, the independent repair industry and, most importantly, consumers.” “Automakers manufacture high-quality, innovative vehicles that provide strong value, safety and convenience to our customers,” said Mitch Bainwol, president and CEO of the Alliance of Automobile Manufacturers. “Accessible, efficient, accurate and competitively priced repair and service are paramount, and franchised dealers and the aftermarket play unique and important roles in the repair process.” ■

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» DrivetrainDiagnostics

By Andrew Markel | EDITOR

In-the-Car Diagnostics: SOLVING TRANSMISSION ELECTRONIC CONTROL PROBLEMS

roubleshooting an automatic transmission can be one of the most intimating diagnostic procedures at a shop. The first reaction is typically, “We don’t do that type of work.” But there is profit in performing drivetrain diagnostics and “in-the-car” repairs. The modern automatic transmission and attached drivetrain has many “mechatronic” parts that control and protect the traditional clutches and planetary gears. These devices shift the gears, lock the clutches and regulate the fluid pressures. Most of these items can be diagnosed and replaced while the transmission is still in the vehicle.

Tool Up Special tools are often needed when diagnosing transmission problems and when overhauling units. In days gone by when transmissions where purely mechanical and hydraulic, all you needed was a set of high-pressure gauges to check line pressures. You also needed a vacuum gauge to check the engine’s intake vacuum and the integrity of the vacuum modulator. But with today’s electronic controls, you need a scan tool, scope and a multimeter.

February 2014 | UnderhoodService.com

Transmission codes and sensor data on latemodel vehicles is accessed through the OBD II diagnostic connector and the Powertrain Control Module (PCM) diagnostic gateway module. But on some vehicles, the information is often found in a separate Transmission Control Module (TCM) or Body Control Module (BCM). Either way, you’ll need a scan tool to access fault codes and operating data. A scan tool can also help you check for communication faults between the PCM and transmission controller if the vehicle has separate computers. Problems here will typically cause the transmission to go into a “limp in” mode that may lock it in 2nd gear. Some transmission problems may or may not set a fault code and turn on the MIL lamp, so it’s important to always scan the PCM or transmission module for codes if there’s a transmissionrelated complaint or driveability issue. Some engine sensor failures (for example, the throttle position sensor, MAP sensor or vehicle speed sensor) can also affect the operation of the transmission. So, it may be necessary to also check these sensors.

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» DrivetrainDiagnostics If you find a transmission fault code, you may have to check the resistance of a solenoid in the valve body, its operating voltage or the frequency of its control signal from the computer. This will require a digital multimeter (DMM) that can read voltage, resistance and frequency or dwell. You’ll also need the applicable service information that includes wiring schematics and OEM diagnostic charts with test specifications for all the components that need to be checked. This kind of information can be found in OEM service manuals, on OEM websites (daily one-time access fees are typically $15 to $25), or through online technical information service providers. You should also check for any technical service bulletins (TSBs) that may be related to the transmission problem. In some cases, it may be necessary to reflash (reprogram) the PCM or transmission module to cure a particular fault.

Diagnostic Strategies and Transmissions When using a scan tool to diagnosis a drivetrain problem, it’s often what is not displayed on the scan tool that will lead you to your final diagnosis. The modern transmission is one of the most connected components on a vehicle. If a PCM or TCM can’t see inputs like engine speed, load or throttle position, it will assume the worst and put the transmission into a safe or limp mode. The transmission does not have discreet sensors connected to the throttle body, crankshaft or intake manifold. Instead, the transmission shares informa18 February 2014 | UnderhoodService.com

tion with the engine control and other modules in the vehicle using a serial data bus. Most vehicles manufactured after 2004 put the TCM or PCM module on the hi-speed, two-wire CAN network along with BCM and ABS modules. The topology for these networks is typically a loop. If a module is not operating, the existing modules can still communicate on the bus. When you’re using your scan tool to solve a transmission problem, you may have to look at the PIDs or datastream from the ECM or BCM to see what modules are talking on the bus. If you can’t communicate with a transmission control module with your scan tool, look for transmission information in the connected modules. The BCM will monitor information from the TCM on gear position so it can tell the instrument cluster what gear to display for the driver. It can also work the other way. If a TCM is not able to communicate with the ECM, looking at the transmission-related PIDs for calculated engine load, throttle position and manifold air pressure may show that the ECM is not communicating on the network or has other issues.

THINKING OUTSIDE THE CASE: Three Causes of Transmission Complaints

Non-Transmission Sensors Causing Transmission Problems Most transmission control modules use inputs from other sensors on the vehicle. If a vehicle can’t accurately calculate the load on the engine, it will adjust the line pressure and slippage to the inaccurate calculation. This can damage the transmission. Sensors used to calculate the load can include the Mass Airflow Sensor (MAF), Throttle Position Sensor (TPS) and Manifold Air Pressure (MAP). If unmetered air is entering the cylinder through a leak, the engine load will be below the actual percentage. This can cause the module to use different shift points and line pressures. This could cause the transmission to delay shifts, overheat and possibly burn the fluid. Maintenance items like a restrictive air filter, dirty air flow meter or blocked crank case ventilation system can change the calculated engine load to the point where it can influence shift points and shift quality.

Wiring Harness Problems The wiring harness and connectors on most transmissions operate in a unique environment. Normal automatic transmission fluid’s conductivity is very low. Hybrids usually have a specification for a fluid that is non-conductive. In most cases, the fluid will not damage or short the connections; the detergents and chemicals will cause the degradation of the materials in the wiring harness that might be outside of the case. Also, check for any damaged wires and connections that could be damaged by impact with road debris, weak or shifting motor mounts and hot exhaust systems.

Grounds Since the mid 1990s, the grounds for solenoids and sensors have changed dramatically. Never assume the chassis ground is coming through the case or valve body. Study the wiring diagrams before trying to diagnose a dead or open solenoid. Some transmissions can have multiple ground points for the solenoids, module and sensors. ■ Reader Service: Go to www.uhsRAPIDRESPONSE.com

» ASE A1 TestPrep

Cylinder Heads and Gaskets

assing the ASE A1 can be difficult. Do not go into this test with the notion that this is an exam for engine rebuilders. Many of the tasks in the A1 task list are required every day at a general repair shop for top-end engine repairs.

From the ASE A1 Task List: A1 #17: Inspect cylinder head mating surface condition and finish, reassemble and install gasket(s) and cylinder head(s); replace/torque bolts according to manufacturers’ procedures.

Surface Finish The level of surface finish is determined not only by the engine materials, but also the gasket type. The aluminum cylinder head surface should be resurfaced to the cylinder head gasket manufacturer’s specifications. In short, the head gasket surface should appear polished rather than rough, with composite gaskets requiring a finish of no more than 45 roughness average (RA). The rougher the surface on an aluminum cylinder head, the shorter the cylinder head gasket life. But check the service information and the recommendation from the gasket’s manufacturer for the recommended surface finish.

February 2014 | UnderhoodService.com

Inspection and Cleaning Any debris that’s snagged and drug across the metal by the milling head may mar the mating surface. Clean bare metal is all you want to see following the initial cleaning process. Checking for cracks in cast iron heads requires a clean surface for the magnetic particle detection powder. Likewise, checking aluminum castings for hairline cracks with penetrating dye also requires a clean surface. Even porosity leaks in aluminum heads and blocks may be masked if there’s a heavy layer of gunk on the metal.

Failures and Cracks The vulnerability of aluminum-head engines to head gasket failure is caused by the aluminum cylinder head

expanding approximately 1.5 times more than the cast-iron block. Although measured in thousandths of an inch, this small and seemingly insignificant difference between the expansion rates of aluminum and cast iron will eventually wear out the head gasket and cause failure. Cracks typically form when a cylinder head undergoes too much thermal stress. Loss of coolant, severe overheating as well as sudden changes in operating temperature from hot to cold can all create the kind of conditions that cause cracks to form. Cracks do not necessarily mean a cylinder head has to be replaced. Many cracked heads

» ASETestPrep once thought to be beyond repair are now being fixed by skilled machine shops

Do Not Reuse Bolts Bolt breakage and uneven gasket loading or loss of torque can cause a newly installed head gasket to leak. TTY head bolts are designed for one-time use because they stretch permanently once they are torqued down. This helps even out the clamping force of the cylinder head on the head gasket.

Head Bolt Installation Dirty or damaged threads can give false torque readings as well as decrease a bolt’s clamping force by as much as 50%. Wire brush all bolt threads, carefully inspect each one, and replace any that are nicked, deformed or worn. If a bolt doesn’t thread into a hole smoothly with finger force alone, there is a problem. Dirty or deformed hole threads in the engine block can also reduce clamping force. Run a bottoming tap down each bolt hole in the block. The tops of the holes should also be chamfered so the uppermost threads won’t pull above the deck surface when the bolts are tightened. Make sure the washers are positioned with their rounded or chamfered side up, and that there is no debris or burrs under the washers. Anaerobic sealant might be required for some head bolts that are exposed to the coolant in the water jacket. When using these products, make sure they are applied to the correct area of the bolt. Anaerobic sealers cure without the presence of air and have specific procedures when it comes to application, torque and cure times. Always look up the specified tightening sequence and recommended head bolt torque values for an engine before installing the head gasket, and use an accurate torque wrench to tighten standard-type head bolts in three to five incremental steps following the recommended sequence and torque specs for the application. ■

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» EmissionsUpdate

By Chris Crowell | Managing Editor

STRIKE IN SOUTH AFRICA COULD HAVE CONSEQUENCES FOR CATALYTIC CONVERTERS

ews broke during production of this issue that platinum miners in South Africa went on strike. This stoppage in platinum mining carries a butterfly effect potential for the U.S. aftermarket. Vehicles cannot meet today’s environmental standards without precious metals. Platinum is one of the key catalyzing, emissions-reducing elements within a catalytic converter. An average catalytic converter contains several hundred dollars worth of platinum, palladium and rhodium. A butterfly effect in chaos theory refers to how a small change in one place can result in large differences down the road in a different time or distant place. A labor issue in another country is no small issue, but that situation half a world away could have real impact on the price, sales and safety of catalytic converters.

Labor unrest background According to reports, around 70,000 employees from the world’s three biggest platinum producers — Anglo American Platinum, Impala Platinum and Lonmin Platinum — are participating in the strike. The mines employing those 70,000 workers are said to contribute 70 to 80 percent of the world’s platinum. A strike of this size will mean a shortage of 9,000 ounces per day. As of press time, the government was attempting to mediate the labor dispute.

The price of platinum Stoppages in production occurred at random times starting in November 2013, enough to drop production 5 percent from the previous year. This unrest, prior to the actual strike, already moved the platinum price needle. The metal’s price climbed about 12 percent in the previous month and six percent during a two-month period. Again, even without knowing how the strike plays out, estimates already show platinum prices to average $1,632/oz. in 2014 and $1,750/oz. in 2015. The price was sitting near $1,480/oz. at press time. In 2011, the post-financial-crisis price of platinum hit its peak of $1,901/oz.

February 2014 | UnderhoodService.com

Converter theft deterrents As the price of platinum goes on the rise, so to will the rate of catalytic converter thefts, especially for trucks and SUVs. The thefts are already hitting the news in Roseville, Calif. One inventive truck owner successfully thwarted a potential theft by welding a piece of metal rebar across his catalytic converter. Resourceful muffler shops in that area are said to be offering a rebar-welding service for a fee. For the those without rebar or a welder, there are products on the market that offer similar protection: • The CatStrap takes advantage of the built-in heat shields in most catalytic converters by routing the strap beneath the shield. If a thief attempts to saw free a catalytic converter, the CatStrap responds with a 125 decibel alarm and hardened steel pins that will actually melt the teeth of the saw blade. • The CatClamp is installed by placing the split clamp assemblies in place before and after the converter. A cable is then routed through both split clamps and around or through the chassis and back through both split clamps. Another potential converter crime prevention measure is etching a vehicle’s license plate number into the converter. The Sacramento Bee article about the rebar crime stopper noted that four automotive service shops in the Roseville, Calif., area offer free catalytic converter etchings by appointment. If catalytic converter thefts start to uptick and make the news in your area, you might consider brushing up on your etching skills or consider selling theft deterrent products. ■

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» Filters

By Andrew Markel

Air Filter Fuel Trim Diagnostics

he modern engine measures two things extremely well, the amount of air going into the combustion chamber with the mass airflow sensor (MAF), and the byproducts that are generated by the combustion event with the oxygen sensor. These measurements allow the engine’s computer to put the right amount of fuel and spark into the cylinder to give the most efficient and cleanest combustion event. Carburetors are stuck with a limited range of fuel trim due to fixed jets. In order to get a cold engine to start, a carburetor would block off the air to a venturi with a choke. The fuel mix would be richer, and the engine could start. The same phenomenon happens on fuel-injected engines with dirty air filters. But fuel-injected engines are able to compensate by changing fuel trim. Since there is less oxygen, the engine will need less fuel. Less fuel means a leaner fuel trim and less power. This adjustment comes at the detriment of performance by taking away fuel. It also works in the opposite direction. If unmetered air makes its way past the MAF sensor, the oxygen sensor will detect a lean combustion event. The ECM will then instruct the injectors to pulse for a longer period of time. This increases fuel consumption and decreases fuel economy. The ECM can only compensate so long before it becomes unbalanced and can no longer add or restrict fuel to achieve a proper oxygen senor reading. This is when codes are set for a too rich or too lean fuel trim. A restrictive air filter may not set a code, but the restriction and compromised fuel trim will hurt the power and efficiency. Replacing the filter and resetting the fuel trims may return the system to normal.

February 2014 | UnderhoodService.com

What are Fuel Trims? Fuel trim is the adjustment the engine computer makes to the fuel mixture to maintain a balanced air/fuel ratio. Fuel trim is usually displayed as a percentage reading on a scan tool. A rich fuel mixture can produce more power (up to a point), but it also increases fuel consumption and emissions. Conversely, a lean fuel mixture reduces fuel consumption but can also increase emissions if the mixture is so lean that it fails to ignite and causes lean misfire. Accurate fuel trim values require an accurate feedback signal from the oxygen sensor, otherwise the engine computer has no way of knowing whether the fuel mixture is running rich or lean. When the engine is shut off, the fuel trim values are retained in the computer’s memory so the next time the vehicle is driven it can pick up where it left off. Erasing the computer’s memory with a scan tool or by disconnecting the battery or the PCM power supply to clear codes also wipes the fuel trim values, which means the computer has to start learning the fuel adjustments all over again the next time the engine runs.

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» Filters How to Read Fuel Trim The engine must be started and running to read the fuel trim information. Choose the option that allows you to read system live data, which varies depending on the scan tool. This will display a long list of sensor outputs and other readings called PIDs (Parameter IDs). There will be two fuel trim values: Short-Term Fuel Trim (STFT) values change rapidly and can bounce around quite a bit depending on engine load, speed, temperature and other operating conditions. Values normally range from -10% to +10%, though the readings may jump as much as 25% or more in either direction. Long-Term Fuel Trim (LTFT) is a longer-term average of what the engine computer has been doing

Understanding Air Filters and Fuel Trims

to balance the fuel mixture over a predetermined interval of time. This value is a more accurate indicator of how the fuel mixture is being corrected to compensate for changes in the air/fuel ratio that are occurring inside the engine.

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If a filter is clogged or restrictive, it will show a negative fuel trim value, which means the engine computer is subtracting fuel — decreasing the pulse width or ontime of the fuel injectors — to reduce the amount of fuel injected into the engine. This is done to lean out the fuel mixture to compensate for what it perceives as a rich running or choked condition. Positive fuel trim air filter diagnostics are a little more complicated. If an air filter or air induction system is delivering more than the normal amount of air, it will cause the oxygen sensor to detect a lean condition. It will add more fuel and cause the fuel trim to be positive. Some possible factors: 1. Collapsed Filter: This could be caused by a clogged wet filter that has become damaged, ripped or dislodged by the vacuum generated by the engine. It will typically flow better than a clean filter. 2. Blocked MAF Sensor: If a filter is made of low quality materials, pieces of the filter media can be dislodged and block the MAF sensor. They can even damage hotwire MAF sensors. 3. Damage to Air Filter Housing: If an air filter housing is damaged, cracked or cannot create a seal around the filter, the air may create turbulence or allow unmetered and unfiltered air to get past the MAF sensor. 4. Bad Filter Design: A lot of engineering goes into an air filter. Base fuel trims are calculated using a stock filter. If a replacement filter used the wrong materials, pleat design or gasket material, it can influence fuel trims. ■

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» DiagnosticDilemmas

By Gary Goms

1999 Dodge Dakota Intermittent Stall

his Month's Diagnostic Dilemma: 1999 Dodge Dakota, 5.2-liter engine, automatic transmission, four-wheel drive, 250,000 miles. Complaint: Engine intermittently stalls after 20-30 minutes of driving time. No diagnostic trouble codes recovered. Client shop reports that engine randomly loses ignition and fuel injector pulse and occasionally loses communication with the scan tool. Black tape covers the “check engine” and “ABS” lights. Diagnosing intermittent stalling complaints is a challenging experience for any diagnostic technician because any number of electrical and mechanical failures can cause an engine to intermittently stall. Most of us immediately narrow this laundry list of potential failures down to the most common few, which include components like the crankshaft position sensor and electric fuel pump. In this case, my client shop had replaced the fuel pump earlier because it consistently failed to produce fuel pressure. After replacing the fuel pump, the Dakota developed an intermittent stalling complaint that would occur after about 20-30 minutes of driving time. Since late summer is the busy part of the season in our area, the client shop called me to help locate the source of the intermittent stalling complaint.

February 2014 | UnderhoodService.com

The Common Elements Let's form a strategy for solving this month's Diagnostic Dilemma by analyzing the various elements of the case. 1) The stalling complaint was intermittent; 2) The stall required at least 20-30 minutes of drive time before it would occur; 3) The ignition coils and fuel injectors would fail to pulse when the stall occurred; and 4) The scan tool would occasionally lose communication. The constant in this case was the 20-30 minutes of driving time required to cause the failure. This is always a major clue because components like distributor pick-ups, ignition modules, power train control modules (PCMs) and crankshaft position sensors often

» DiagnosticDilemmas require that amount of time to reach operating temperature. Next, the ignition coil and fuel injectors were losing pulse, which might indicate crankshaft position sensor failure. Lastly, the shop's scan tool losing communication with the PCM was an issue, which could also be caused by a faulty diagnostic link connector (DLC) cable or scan tool. So that was not an issue at this time. To determine the common elements of a case, I printed an engine performance electrical schematic. In many cases, I tape multiple pages together to help trace various circuits. This helps familiarize me with the basic circuitry and to make my own highlights and notations on the operation of various circuits. These annotated schematics also provide a quick reference for

pin-testing the PCM and the Power Distribution Center (PDC). Since it powers the ignition and injector circuits, the auto shut down (ASD) relay deserves particular attention. According to the schematic, the primary side of the ASD relay is powered from the ignition switch through a junction block equipped with a 10-amp fuse. Current flows from the junction box to the ASD relay’s primary solenoid coil. When the ignition is turned on, the PCM is activated through the key-on circuit, as are the ASD and fuel pump relay primary, ignition coil and fuel injector circuits. But the ASD relay operates only when its primary circuit is pulled to ground by the PCM. Obviously, the ASD relay circuit is a primary suspect in this intermittent stalling complaint.

Unraveling the Data We've all heard about making decisions “in the fog of war.” The same can be said of making decisions “in the fog of diagnosis” because, while

Issues like the aftermarket relay located at the upper right-hand corner of the photo raised some questions when diagnosing the intermittent stalling complaint on this venerable 5.2L Dodge Dakota.

UnderhoodService.com 33

» DiagnosticDilemmas

This photo illustrates how I use electrical schematics. Critical circuit pins are highlighted in yellow and annotated in red. Working from a schematic is the quickest way to cut your diagnostic time.

we have some of the facts, we don't have all of the facts. My immediate diagnostic strategy was to collect the rest of the facts by connecting my own scan tool to evaluate the intermittent no-communication problem and to collect codes and data. The codes included a P0443 evaporative failure code, which was irrelevant to our stalling problem. Next was a more significant P1678 DTC, indicating, according to the scan tool, that the mechanical instrument cluster wasn't receiving bus communication messages. Polling the various on-board modules indicated a glaring “Body Module Fault” in the body control module and a number of two-digit flash codes in the ABS module.

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OK, we know we're losing the ASD relay and now we have some very relevant bus communications DTCS.

Diagnostic Scenarios The ABS module had been replaced with a used module that might not fit this particular VIN. Although the ABS fuse had been removed because the ABS pump wouldn’t deactivate, the module was evidently still active on the bus communications circuit. Perhaps the ABS module was pulling down the bus circuit, perhaps not. But a bus communications problem doesn’t adequately explain the malfunction in the ASD relay circuit. Nevertheless, when I entered Chrysler’s bi-directional Automatic Test Mode (ATM)

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» DiagnosticDilemmas to diagnose the instrument cluster, all the gauges activated when commanded. My next step was to install a relay circuit tester attachment under the ASD relay, which allowed me to test the relay’s primary power, ground and B+ output to the ignition coil and fuel injectors. At that time, I noticed that the primary for an aftermarket relay had been spliced into the power distribution center (PDC) wiring. Next, I connected a fuel pump pressure tester so I could keep an eye on the fuel pump and pump relay activity.

Back to the Scan Tool

Connecting a fuel pressure gauge is a simple way to simultaneously monitor the fuel pump relay and fuel pump activity.

With my underhood diagnostics in place, it was time to start the engine and record scan tool data. Sure enough, after about 30 minutes of run time, the engine stalled. The fuel pressure gauge indicated specified pressure, so I tested the ASD test jumper attachment to see if the PCM was pulling the primary circuit to

ground. With B+ voltage present at both primary terminals, it was obvious that the PCM wasn’t pulling the ASD primary circuit to ground during cranking. Then my scan tool lost communication. More ominously, a bright green “no bus” message appeared in the odometer display. A quick polling of all modules indicated that all modules were reporting except the PCM. Quickly, I disconnected the scan tool from the DLC and tested the No. 16 port for B+ (present), No. 4 port for ground (present, using a test light), No. 5 port for ground (present, using a test light) and, most important, the No. 3 and No. 11 ports for the presence of the required +2.5, -2.5 voltage at the Chrysler Collision Detection (CCD) bus communications signal ports (not present). The system was behaving erratically and the values were changing very quickly, so I didn't check for activity at the serial command interface (SCI) ports, which allows the scan tool to communicate with the PCM and the transmission control

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36 February 2014 | UnderhoodService.com

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» DiagnosticDilemmas module (TCM) where applicable. The No. 2 port is the programmable communications interface (PCI), which allows communication with the body control module (BCM) where applicable. Also apparent was the intermittent lack of fuel level, coolant temperature and oil pressure gauge activity on the instrument panel (IP). Going back to our schematics, it's important to note that all three gauges report directly to the PCM and from the PCM to the instrument cluster. Since the PCM was evidently not reporting to

the scan tool or to the instrument panel, a quick check for power and ground was in order. Using a test light with a No. 194 bulb, I verified the availability of No. 2 key-on and No. 22 fused B+ voltages as well as the integrity of the two redundant PCM grounds (No. 31 and No. 32). Next, testing directly at the No. 3 ASD relay pin yielded full battery voltage, which indicated that the PCM was not grounding the No. 3 pin during cranking. At this point, I used a non-contact pyrometer to verify that the PCM had reached about 110° F operating temperature, which is normal for this vintage of Chrysler PCM.

Conclusions

This “no bus” message at the odometer display indicates a bus communications failure in the Dodge Dakota's CCD bus network.

1) The PCM was the only module lacking communications; 2) The IP was not receiving fuel, oil and coolant messages from the PCM; 3) The PCM was not commanding the ASD relay closed by grounding the ASD relay primary circuit; 4) No voltage was present at the No. 3 and No. 11 CCD bus terminals located in the DLC; and

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» DiagnosticDilemmas

Testing for adequate key-on and B+ powers and redundant grounds at the PCM is a must for analyzing any suspected PCM failure.

5) The PCM had key-on and B+ voltages as well as redundant grounds. All of the diagnostic arrows were pointing at a failed PCM. While the failure of the PCM’s ASD driver was the root cause of the stalling complaint, the failure of the CCD bus system produced the most apparent and visible symptoms of a failing PCM. As events developed, it was apparent that the CCD signal was being intermittently lost at the PCM. With that in mind, the key to solving this month’s Diagnostic Dilemma is understanding the basics of the CCD bus communications system. Chrysler’s CCD bus is one of the most comprehensive systems introduced during the 1990s. To clarify, the term “collision detection” has to do with how the system separates bus messages being sent by various modules. From a more global perspective, it’s important to begin mastering the basics of Go to www.uhsRAPIDRESPONSE.com

bus communications. Currently, all vehicles sold in the United States since 2008 use the highspeed Controller Area Network (CAN) protocol to network onboard modules and to prioritize their messages. Bus communications is a complex subject and there are a number of excellent training DVDs available that provide detailed information on how bus communication and CAN systems operate. Since each bus communication and CAN system is configured differently for a wide range of applications, I recommend moving from basic to complex in the learning process. Service information can be very sketchy on some early applications, but most of the service data on current CAN applications are generally very complete. With that, I close the book on this case study of the '99 Dodge Dakota with an intermittent engine stalling complaint. ■

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» DiagnosticPathfinder

By John Forro

Cold Weather Diagnostics: When the Temperature Goes Down, So Can Some Modules.

usually like to see a problem first hand a half dozen times before I feel comfortable calling it a silver bullet. However, I have seen this same problem occur three times now this winter season, and I think I have found the issue. Silver bullets can be a real time saver. Often I am asked when a new Silver Bullet Book (www.johnforro.com) will be made available. I have found over the last several years that vehicles are simply made better and are not having as many pattern failures as they once did. Sure, there are still some, like various vacuum leaks, but nowhere near as many as we once had.

No Crank, No Start The subject vehicles were 2002-2006 Ford trucks — the first was a 2002 Ford F-150 with a 5.4 liter, second was a 2006 Lincoln Navigator with a 4.6 liter and finally a 2004 Ford F-250 with a 5.4 liter engine. All of the customer complaints with these vehicles were the same: “The vehicle will not crank/start when cold.” One customer added that it would be fine if it was kept in the garage overnight, and one handy guy said if he jumped the starter it would be fine. These three vehicles were not at my shop all at once, but over a period of approximately 6-7 weeks.

For this article I will discuss the first vehicle, the 2002 Ford F-150, in detail. The other vehicles had similar diagnostic processes. The customer wanted to have the vehicle towed in to my shop because it was having trouble starting. Some mornings it would start while others it would not. This person was not a regular customer of mine and was recommended to me by a daughter-in-law. After providing the address to have the vehicle towed in, I tried to rapidly finish up the vehicles I was currently working on to make room in the shop so the tow truck could just drop the vehicle inside upon arrival (big mistake). I normally try to do this when possible because it is difficult for me, as a one-man facility, to get the dead vehicle in by myself.

First Try The vehicle shows up about an hour later and is dropped off inside the shop as I had planned. The vehicle sat inside my shop at 58 degrees while I proceeded to finish up another vehicle I was working on. After another half hour I turned my attention to the F-150. I wrote up the vehicle, tried cranking with no luck, but I noticed the security light flashing rapidly.

February 2014 | UnderhoodService.com

Âť DiagnosticPathfinder This warranted a scan of the security system as well as all the other modules for codes. No codes from any of the modules were found. At this point I thought I had a PATS (passive antitheft system) issue, but I decided to take a visual inspection both under the hood by the ECM and under the dash by the ignition switch areas for any potential obvious wiring conditions. Everything looked up to par in both areas. I even went as far as unplugging the ECM and looked at the terminals both inside the ECM and the harness side of the connectors. Once I went back inside the vehicle, the problem was gone! The truck cranked and started with no issue several times. At this point I considered everything I did wrong thus far. I shouldnâ&#x20AC;&#x2122;t have disturbed anything. I should have looked over a schematic and performed some specific circuit testing at the various ECM and ignition switch circuits. I would now have to wait to see if the problem would come back. Wasted time.

I left the vehicle in the shop overnight, and in the morning it started without any problem. I parked the vehicle outside and throughout the day it started without any issues. I had no choice but to call the customer and give the vehicle back without figuring out the problem or making any money.

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» DiagnosticPathfinder Second Try About a week later the phone rings again and, as we all already know, the vehicle was once again not cranking and was getting towed back in. My mind started racing to formulate an attack plan. What will I test first? What did I do last time to make the problem disappear? Are there any similarities between this day and the last day that it would not start? The only similarity between both days was that the temperature outside was very cold. Much like the entire country, it has been an unusually cold winter here in Ohio. This time I had the tow truck place the vehicle outside. Once the vehicle arrived I made sure the problem was present — no crank and security light flashing. I scanned for any related trouble codes again, and this time I pulled a code indicating it was unable to communicate with the ECM.

would have been able to figure this out the first time around if I didn’t drop the vehicle inside the shop. A new PCM, with an installed flash and programming the keys, repaired the vehicle. Both of the other vehicles mentioned earlier were repaired with the same procedures. Looking at the upcoming forecast, we may have more of these vehicles showing up in the near future. ■

Cold Car, Hot ECM I quickly printed a schematic to check the ECM’s power and grounds and, upon verifying they were present, I removed the ECM and brought it inside the warm shop. After an hour or so I took the ECM back outside and installed it into the truck and the vehicle started right up. I was on to something. Could I have a bad circuit board inside the PCM, or is it a mating problem at one of the ECM connectors because I disturbed them both times to get the vehicle started? I let the vehicle sit outside longer to allow the problem to reoccur. This time, I took my heat gun outside and applied heat to the ECM for a couple of minutes. After a little heat, the vehicle started. This confirmed my suspicion of a bad board inside the ECM. I probably

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» TechTips This month is sponsored by:

The 1998 Jimmy-Blazer Fuel Tank Dilemma The Chevrolet Blazer and GMC Jimmy are popular GM vehicles, and in 1998 they were equipped with a number of vehicle options that make determining the correct fuel module for either application confusing. These vehicle applications could potentially offer three different fuel modules to fit. They are FG0072, FG0052 and FG0071. The FG0072 fuel module is designed for use on two-door applications. This is easy to identify, so there is little confusion regarding these applications. The confusion typically surrounds the remaining two fuel modules, FG0052 and FG0071, which both fit four-door applications. The catalog indicates that FG0052 fits the fourdoor Blazer with an 18-gallon fuel tank, while FG0071 fits a four-door Blazer exc. 18-gallon fuel tank. Regardless of the descriptions, mistakes can be made when fuel tank size cannot be determined. If you are having difficulty determining the tank size, see if the tank is made of plastic or steel. The 18-gallon tank option is made of plastic, using FG0052. The exc. 18-gallon tank option is made of steel, using FG0071. If you do not know either the fuel tank size or material, you can determine the correct module by examining it once removed from the fuel tank. The FG0052 fuel module, which is used in the 18gallon plastic tank, uses a cuff-style seal and cover design as shown in the photo. By spending minimal time determining the type

This is the seal and cover design used on the FG0071 fuel module. This design was made for use in a steel fuel tank.

This is the seal and cover design used on the FG0052 fuel module. This design was made for use in a plastic fuel tank.

of fuel tank and/or module used in these applications, you can reduce part returns and increase customer satisfaction. Courtesy of Delphi.

GMC Sierra: Has No-Crank/No-Start Condition Vehicle: 2009 GMC Sierra 1500 SLE 5.3L, V8, MFI, OHV, VIN 0, Eng Desg LMG

Customer Concern The battery was jump-started with the key on, which resulted in a no-crank, no-start condition. Theft deterrent module (TDM) DTC B3060 is present.

The module will perform the relearn, work properly three times, then go back into the failure mode.

Tests: 1. Verify battery voltage on the red/white wire at pin 1. 2. Verify switch voltage on the yellow wire at pin 2.

February 2014 | UnderhoodService.com

3. Verify a good ground on the black/white wire at pin 3. 4. Verify communications on the dark green wire at pin 4. 5. If OK, replace and program the TDM. Courtesy of Identifix’s “Five Fast Fixes”

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» TechTips GM: Power steering pump replacement tips Models: •1997-2010 GM passenger cars and light duty trucks, including Saturn •2010 and prior HUMMER H2, H3 •2005-2009 Saab 9-7X An analysis of returned power steering (PS) pumps that had been replaced for noise, no power assist, no or low pressure and leaking conditions has indicated a high number of "No Trouble Found" results. When attempting to repair a power steering concern, the steering system analyzer should be used to assist the technician in a successful diagnosis. The Saturn ASTRA, however, does not use the Power Steering System Analyzer.

In addition, extensive warranty analysis has shown that the following situations are all significant root causes of PS pump failures: • Improper pulley installation • Re-using the O-rings • Using fluid other than the OE-specified steering fluid • Failure to flush the PS system

GM recommends the following tips for replacing a PS pump: 1. Low or no pressure from the PS pump may be the result of dirty or contaminated fluid, which could cause the pressure relief valve to stop functioning. Using the proper tools, flush and bleed the PS system. Any residual contaminants will result in pump failure. 2. When removing the pulley, use the proper special tools. Because the pulley alignment is critical, distorting the pulley may damage bearings on the new PS pump. Note: Some new PS pumps may not include a new O-ring. Please refer to the appropriate Parts Catalog. 3. Be sure to use only the new O-rings included with the PS pump. The new reservoir O-ring must be lubricated with OE-specific PS fluid prior to installation. Also make sure that the control valve O-ring is in its exact groove position and is NOT covering the pressure bypass hole. 4. Bleed the PS system according to the procedures/recommendations in the service information. Following these procedures and using the correct tools and fluids should help ensure that the new PS pump operates properly. Skipping steps may cost you time and trouble later. Courtesy of ALLDATA

Failing Pilot Bearing / Bushing Most rear wheel drive, and some front wheel drive, vehicles with manual transmissions use a pilot bearing/bushing. The pilot bearing/bushing supports and centers the transmission input shaft and clutch disc. When the clutch is disengaged, the pilot bearing/bushing allows the flywheel to maintain engine RPM while the input shaft is slowing down and stopping. Types of pilot bearing/bushing include conventional ball bearings, needle bearings and sintered bronze bushings. 48 February 2014 | UnderhoodService.com

When a pilot bearing/bushing fails, a vehicle may exhibit: • No release; • The transmission may pop out of gear; • Noise; • Vibration; and • Catastrophic failure of the transmission if not fixed Early signs of the pilot failing may be noise whenever the clutch is disengaged. The driver may also notice that the transmission is difficult to shift

Âť TechTips

Figure 2

Figure 1

between gears or hard to put into reverse or first gear when stopped. When the pilot is failing, or has failed, the input shaft will be allowed to walk around causing it to go off center. When this happens, the transmission input shaft will begin moving around inside the transmission causing the gears and synchronizers to be off center resulting in the transmission popping out of gear. If the vehicle has a high output engine, the misalignment will cause the input shaft gear to not mesh with the counter shaft gear properly and ultimately will cause the gears to fail. (see figures 1 and 2). When a clutch is replaced, the pilot bearing/bushing should always be replaced as part of the service. Courtesy of Schaeffler Group USA / LuK â&#x2013;

UnderhoodService.com 49

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AMSOILâ&#x20AC;&#x2122;s new OE Synthetic Automatic Transmission Fluid is available in Multi-Vehicle and Fuel-Efficient formulations. AMSOIL OE Synthetic ATF provides outstanding protection in normal and severe service, resisting wear on vital parts and extending transmission life. It is thermally stable, guards against the harmful effects of thermal breakdown and helps components stay clean by resisting heat-related evaporation and viscosity loss. Reader Service: Go to www.uhsRAPIDRESPONSE.com

Delphi Product & Service Solutions announced 12 new ignition coils to its engine management portfolio covering almost 7 million GM, Nissan, Hyundai, Toyota, Chrysler and Volkswagen applications from 1986 to 2012. Part numbers: GN10265, GN10304, GN10305, GN10341, GN10345, GN10345, GN10348, GN10349, GN103050, GN10351, GN10352 and GN10333. Delphi ignition coils are backed by a 3-year/36,000-mile warranty. Delphi uses a winding process technique to control the length of wire between adjacent windings. Reader Service: Go to www.uhsRAPIDRESPONSE.com

CRP Automotive, a source of OE-quality replacement parts for Asian and European vehicles, offers coverage on Asian and European applications with its AJUSA Cylinder Head Bolt Kit program. The program features a line of torque-to-yield (TTY) head bolts that come packaged as sets to meet vehicle specific applications. The sets are provided in a shrink-wrapped cardboard box with assembly lube included. Reader Service: Go to www.uhsRAPIDRESPONSE.com

50 February 2014 | UnderhoodService.com

Âť Shop The PlatinumNAPAFilter offers technology for the latest advancements in synthetic oil and performance oil filters. Featuring a host of oil filter innovations, including wire re-enforced fully-synthetic media, ultra-durable Hydrogenerated Nitrile compound anti-drain back valve (where applicable), this oil filter provides the ultimate protection in the NAPA Family of oil filters. Visit www.napafilters.com for more information. Reader Service: Go to www.uhsRAPIDRESPONSE.com

Barâ&#x20AC;&#x2122;s Leaks Head Gasket & Cooling Sealant (P/N HG-1) repairs blown head and intake gaskets, cracked cylinder heads and cooling system leaks. It can be poured directly into the radiator of a vehicle capable of idling for 15 minutes without overheating or losing coolant. The liquid sealants contained in Head Gasket & Cooling Sealant are absorbed by the gasket material, harden, then form a barrier. Head Gasket & Cooling Sealant now comes packaged in a box for greater shelf presence and visibility. Reader Service: Go to www.uhsRAPIDRESPONSE.com

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» DiagnosticLogic

By Andrew Markel

EGR and Secondary AIR Systems

he perfect internal combustion vehicle would be able to put the exact amount of fuel and air into the combustion chamber. If the perfect combustion event happened, you would get nothing more than water and carbon dioxide. There would not be any unburned fuel or oxygen. It would also be at the right temperature so oxides (“hyperactive” oxygen turned on by higher temperatures) would not combine with nitrogen and carbon to form nitric oxides (NOx) and carbon monoxide (CO). This perfect car would not need a catalytic converter or any other emission-control device. We are not there yet, in the mean time, we have exhaust gas recirculation systems (EGR), secondary air injection and catalytic converters.

EGR Systems EGR systems put a small amount of inert gas into the combustion chamber to control the temperatures. Since exhaust gases do not typically burn, this lowers the combustion temperature and reduces NOx emissions from the engine. When things heat up in the combustion chamber to temperatures around 1,300° C or 2,500° F, oxygen and nitrogen start combining with each other and form NOx and CO. By putting exhaust gases into the combustion chamber, the air fuel mixture is watered down by the inert exhaust gases. This slows down the combustion process and lowers combustion temperatures to levels where NOx does not form. Unlike older EGR systems, modern EGR systems work constantly, not just during deceleration or closed throttle conditions. Newer vehicles with variable valve timing on both exhaust and intake camshafts can adjust timing so that a small amount of exhaust gas is sucked back into the chamber during the intake stroke.

February 2014 | UnderhoodService.com

Secondary Air Injection Systems Secondary air injection systems pump outside air into the exhaust stream so unburned fuel can be burned. Early systems have a belt-driven air pump. Newer aspirated systems use the vacuum created by an exhaust pulse to pull air into the pipe. The latest systems use an electric motor to pump air. These systems are critical for the life of the catalytic converter. Electric motor systems can be found on many new vehicles like the GM LS series, Toyota V8s and California emission Ford 3.8 V6s and 2.0 four cylinder. These systems typically are active during the first 20 to 120 seconds of engine operation by forcing air downstream into the exhaust manifolds to oxidize the hydrocarbons and carbon monoxide created by running rich at startup. The system injects the correct amount of air using inputs like coolant temperature, air temperature and oxygen sensors.

Catalytic Converter Under ideal conditions, a three-way catalyst can reduce somewhere between 50% and 95% of NOx emissions and 99.9% of the unburned fuel. It is the last stop for pollutants, and if an emissions system upstream is compromised, it can only compensate so much before tailpipe emissions increase.

Diagnostics To properly diagnosis a high-emission vehicle, you must look at it like an engineer looking at the entire system, from the air intake to the exhaust pipe. When a vehicle is engineered, it must meet a specified emission level. To do this, an engineering team will balance the systems and make them work in harmony so the price is affordable. If a vehicle has a combustion chamber design that has higher than normal temperatures, the engineers will balance out the amount of exhaust gases introduced to the combustion chamber to the size of the converter so the vehicle meets mandated emission levels and the warranty period. ■

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