9 minute read
Diagnostics Doctor
Steve Rothwell answering your ENGINE MANAGEMENT queries
FIAT SEICENTO
Advertisement
IN ASSOCIATION WITH
Trouble codes
QThis is my son‘s 2001 Fiat Seicento Sporting 1.1 which I think has the FIRE engine in. A couple of days ago he was driving home and the EML came on and it went into limp-mode. He managed to nurse it home and we have done the following: OBD-II code read P0351 - ignition coil primary/secondary circuit malfunction. It has suggested an open circuit.
We have checked the following: ignition coils, which seem to be getting power and sparking. Changed the HT leads as they looked like the originals! I couldn’t see an obvious wire break but didn’t delve too deeply.
I suspect the sensors – yellow ones on top of the injectors (I think) but have struggled to get any off to check – I don’t want to break them if it’s not likely to be them.
I’ve cleared the code, but EML is straight back on (unsurprised!). The car appears to be firing on three cylinders and is obviously idling very roughly. Mechanically I am happy doing things – but electrics have always stumped me a bit so any help gratefully received.
It’s booked in with a local Fiat independent soon, but I would at least like to have done some focused tests to see what it may be – every day’s a school day – regardless of me not liking electrics.
Richard Taylor www.launchtech.co.uk The Seicento coil which covers two cylinders.
AThe code you have P0351 indicates that the ignition coil A, primary/secondary - circuit has a malfunction. This is indicating the coil which supplies cylinders 1 & 4. This may be in the loom, connections or the multiplug to the ECU. It may also be a problem in the ECU itself. But the problem will be in this area.
The first check is to swap the coils around. If the code remains the same then the coil is not the problem, if the code changes to P0352, then the coil is at fault and will need renewing.
If the swapping the coils around does not make a difference, then the next step, as you have already looked at the connecting plug on the coils, would be to check the ECU and look for any signs of corrosion or verdigris on the ECU terminals.
The wire from the coil A should go to terminal 1 on the ECU, and the wire from the coil B should go to terminal number 19.
If no problems can be seen on the actual terminals or connections, then the next step would be to use an ohm meter to check for any resistance in the wire between the coil and the ECU. This should highlight any problem in this area.
MORGAN PLUS 4
Hunting from cold
QI am having cold start issues with a 2014 Morgan 2.0 Plus 4. The car has a Ford Duratec GDI engine from the likes of a Focus ST and is hunting from cold, backfiring for the first couple of minutes and with a strong smell of running rich. Thereafter everything is fine when it gets warmer.
I had a dealer plug in the manufacturer code reader and found no error codes. In addition, I have cleaned the MAF sensor, changed the plugs and confirmed there is no leaks between the MAF sensor and the throttle valve. I was considering replacing the pre-cat O2 sensor with the Ford part number 8F9A 9Y460 GA. However, the local Ford dealership quoted over £300 for this! It’s a 5-wire sensor with White, Black, Red, Grey and Yellow wires.
Ken Wilson A The two symptoms you have are slightly contradictory to those I would expect. Normally it is a weak mixture which will cause a backfiring issue, but the hunting and the strong smell of fuel does suggest a rich mixture.
As things do settle when the engine temperature rises, I would as a first step ensure that the temperature reading from the air and coolant temperature senders are matching the actual temperature. It should be possible to check the temperatures using live data on a scanner and if the engine control module is receiving incorrect information, then this would explain why this problem is only apparent on a cold engine.
Faulty temperature sensor both coolant and air temperature which is normally recorded within the MAF sensor can be incorrect without flagging up a fault code. I would also add that I have seen many faulty MAF sensors which do not trigger a code.
As a start it may be worth ensuring that the heater on the O2 sensor is good and using an ohm meter on the two heater wires should confirm that the heater is not open circuit, although I would expect this to flag up a code. The heater wires from the details I have should be white/ blue and white/green providing that Morgan have used the Ford wiring loom.
As this problem may be related to a timing issue, another common concern can be caused by the crankshaft sensor, and this may be a temperature related problem. As the crankshaft sensor is a cheap component which can be renewed quite easily, I would consider this as an option.
enquiries@launchtech.co.uk
01752 344 989
JAGUAR STYPE
Performance limited
QI have another longstanding niggle on my S-TYPE 2.7 TD in as much as it throws a performance limited message on the dash occasionally and always only after a cold start, never when the engine is warm. This is easy cured by restarting the engine, whereupon it works OK after that, no matter how often you have to restart the car on that particular day. I have hooked up the code reader and I am getting two codes P0046 and P004B these relate to the turbochargers.
Are the codes specific to one turbo (the engine has a turbo on each cylinder bank), ie. does P004B mean bank B which I take it would be the passenger side or could the fault be either side? I take it bank 1/A relates to the driver’s side and bank 2/B relates to the passenger side?
Steve Forsyth
AThe code P0046 refers to the Turbocharger (TC) boost control solenoid/ supercharger (SC) boost control solenoid - circuit range/performance, and the code P004B refers to the Turbocharger (TC)/supercharger (SC) boost pressure control B - circuit range/performance. The B in the code should indicate that the problem is in the circuit, not the mechanical operation of the unit. But the codes give no indication of which bank the problem is associated with. The Jaguar workshop manual lists only the seven-digit codes but these do not include the codes read from your vehicle.
The closest match I have is P0045 which is variable geometry turbocharger actuator open circuit right-hand bank, and P004A which indicates that the turbo actuator circuit is open on the right-hand bank. Or the code P0048 which indicates that the turbo actuator circuit is high on the right-hand bank.
It is unfortunately not unusual for the manufacturers code to not always cross over to an easily-detectable code when read from and EOBD scanner.
The turbochargers on the 2.7 diesel engine are variable geometry units which means that the amount of boost generated can be varied according to the engine load as well as the speed. The variable geometry solenoid is operated by the engine control module in response to the prevailing conditions.
With the codes and the symptoms you have, I would suspect that the fault is either due to a poor connection of the actuator or possibly an internal actuator failure. As the problem does only occur when the engine is cold, this is more likely to be the actuator, which once warmed up will then perform correctly, but after standing overnight or longer, may become sticky.
To narrow down the side of the problem, it may be necessary to disconnect one side at a time, and then see which codes are triggered by the disconnection of the actuator. This should give a good indication as to the side of the problem.
PEUGEOT 308
Retrieved codes
QSorry to bother you again but my 2013 Peugeot 308 1.6 HDi has got two fault codes. l took it to my local garage and the codes P2562 and P1497 came up but the mechanic could not find the fault. Can you help please?
Will Beck
AFirst let me say it’s not a bother, it’s what I am here for. The code P2562 indicates a fault in the turbocharger (TC) boost control position sensor, and the code is flagged due to a circuit malfunction. The code P1497 is indicating a fault in the turbocharger (TC) vane position sensor which is showing an under-boost condition.
The most likely cause of both of these codes is a failure in the wiring circuit. And so, the wiring to the wastegate actuator would be the first area to check. If no signs of failure in the loom or connecting plug are visible, then the next check would be the actuator.
There are three simple checks that can be done, the first is to ensure that the actuator has a 5V feed with the ignition on, this should be checked with the plug connected between pin number 3 on the actuator plug and earth. Providing the feed is good the next check is to ensure that whilst running the voltage between pin number 1 and earth is around 3.7V. This again is done with the multiplug connected.
The last check is with the engine off and the multiplug disconnected, testing the ohm reading between terminals 2 and 3 this should read around 5000 Ω. If this reading is not correct then the actuator is the likely problem.
Diagnostics Doctor
Diagnostics Doctor is a FREE helpline service for CM readers – including trade readers – who are struggling with diagnostic/engine management related faults. Steve Rothwell will answer all your queries. He will need as much detail as possible: MAKE, MODEL, YEAR, ENGINE CODE and NUMBER PLATE of your vehicle – and the type of management system installed. Obviously, Steve will not be able to assess the vehicle up close, so his answer will be on the basis solely of your description. This is a FREE service and it may take some time to respond to certain problems. If you would like to receive a personal response via post, please enclose an SAE. e-mail: cmdiagnostics@yahoo.co.uk
Write to: DIAGNOSTICS DOCTOR CAR MECHANICS, KELSEY MEDIA THE GRANARY, DOWNS COURT YALDING HILL, YALDING, KENT ME18 6AL
Common abbreviations
ATS Air Temperature Sensor AFM Air-Flow Meter – not a MAF type (see below). It could be, for example, a vane type CAS Crank Angle Sensor CPS Crank Position Sensor CTS Coolant Temperature Sensor ECT Engine Coolant Temperature ECU Electronic Control Unit EGR Exhaust Gas Recirculation – meters exhaust gas back to the intake manifold EML Engine Management Light EMS Engine Management System EPC Electronic Power Control FCR Fault Code Reader HT High Tension – ignition output to the spark plugs IAV Idle Air Valve ISCV Idle Speed Control Valve – usually operated by a motor controlled by the ECU LOS Limited Operating Strategy – if the ECU detects a malfunction, it runs a programme to allow the car to still go, but at reduced efficiency MAF Mass Air-Flow meter MAP Manifold Air Pressure MIL Malfunction Indicator Lamp PCV Positive Crankcase Ventilation – takes crankcase gases and recycles back to the inlet system TBPS Turbo Boost Pressure Sensor – used by the ECU to regulate turbo output TPS Throttle Position Sensor VSS Vehicle Speed Sensor WOT Wide Open Throttle
enquiries@launchtech.co.uk
