ATS 6004XM WiFi scope
Working smarter CONSIDERING THE POSSIBLE CAUSES AND FINDING WAYS TO ELIMINATE SOME OF THE OPTIONS IS MUCH EASIER WITH THE RIGHT TOOLS AND THE RIGHT SUPPORT
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quipment supplier AECS director Herbert Leijen says AECS’s technical help desk was called in to help diagnose a crank/cam correlation fault code for the left-side engine bank of an Audi RS5 2011 4.2 V8 FSI. The workshop had checked with the Launch Scanner and tried in vain to reset the code and
Cam actuators in an Audi engine
do a cam relearn, but it was unsuccessful. AECS suggested measuring all four camshaft hall sensors’ signals to see if the phasing of the left and right banks on this vee engine were matching. The VVT system’s camshaft adjuster solenoids were disconnected locking the hydraulic advancers
ATS 6004XM WiFi scope recording of the four camshaft sensors
ATS WiFi 6004XM scope recording with added crank angle math trace
After the repairs, we can clearly see the left-bank exhaust camshaft is in line with the right-bank exhaust camshaft
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Auto Channel Issue #48 July 2022
in the fully retarded position to eliminate possible cam phasing fluctuations created by the ECU. Now the left bank should be the same as the right bank. The recording shows the left intake camshaft is not in alignment and is advanced compared with the other camshafts. Possible causes include the left exhaust camshaft has jumped on the timing chain, or the camshafts advancer on one of the left-side bank camshaft has seized. To eliminate a cam chain issue, the diagnostician was keen to see the phase shift in crank angle degrees. The four-channel scope was connected to the crankshaft and the two intake camshafts. Added to the traces of recording was a ‘Maths’ channel, a trace that can be added to a live recording. In this case the Maths channel uses the rise and fall of the crankshaft teeth, adding and subtracting, to calculate and display crank angle degrees as a trace. This is only one of the unique and super useful functions of the ATS scope. Having found no issue with the crankshaft, the workshop was now in a position to quote with confidence. After the customer accepted the quote, the engine was disassembled. The mechanical timing was all correct, but the left-bank intake camshaft advance mechanism had seized. We see this more often in engines with super-long service intervals, where the oil has been left in for too long. The sludge will seize the actuator by filling its cavities, and you cannot flush it through. The actuator and the intake VVT solenoid were replaced and the engine was reassembled. The vehicle owner was presented with a bill that was well under potential estimated costs as the diagnostic time had been significantly reduced with the right tools and support. No “swapnostics” were done and no unnecessary parts were used. Herbert says the speed and accuracy a quality diagnostic oscilloscope like the ATS and Launch scan tool can add to repairing cars is not to be underestimated. He says workshops should avoid cheaper or inferior scopes that only claim to do the same job and which have non-existent support services. Suppliers need to understand how their diagnostic equipment works and be able to prove they have a history of supporting their clients.
