Peter Badore

I am working on a high miles 1999 A6Q 2.8l AHA V6 with engine computer 4D0 907 551AH that has a short to positive for the fuel injector no.4 (N33). Scans with VCDS also show DTC 16655 "short to plus won't desafe" and two unknown error codes 64582 and 09025. In other VAG cars that I worked on an injector short to positive DTC was due to a failed injectors. In this 99 A6Q replacing the no.4 injector did not remove the fault code and the engine runs poorly at idle. My question is this: could a failed injector driver circuit in the ECM also set the short to positive DTC and as a result could the no. 4 injector be held open all or most of the time? The car's owner complains that the exhaust has a "bad" smell most of the time.

Theresias

Start with posting an Auto-Scan please.

Peter Badore

That scan was deleted and the no 4 injector DTC went away after a few erase dtcs.
Now bank 1 is reporting cylinders 1,2 and 3 with massive misfirings at below 1600 RPM, above 1600 rpm none or 1 or 2 only. Do you know what the parameters are for setting DTCs no. 17930 and 17927 camshaft adjuster malfunction? Can either 17930 or 17927 be generated by running the engine with the transmission in neutral not under load? I am guessing that they can not be generated unless the engine is under load? On 8-20-11 for the 99 A6Q 2.8l AHA engine I found that the bank 1 lower camshaft tensioner pad was broken into many pieces and that the adjuster was jammed in the up position. The large number of misfires on cylinders 1, 2 and 3 was caused by the failed tensioner. Also, on my 01 A6 2.7l 6 speed car the intake camshafts do not adjust at any speed without a load on the engine.