Misfire problem
My beloved car (Sl65AMG) has now got the following problem:
Cold startup is fine, driving around for approx one hour fine, full acceleration and driving is fine - engine ok! But then suddenly MIL light on and almost all power are gone + strange sound in the exhaust (like only 6. cyl. is running). Right side bank (6 cyl.) running fine, left bank, some or all cyl. not running correctly. The smell from the left tailpipes (left bank) is unburned fuel, the right pipe (right bank) is ok! The below codes are stored.
Switch off and on the ignition – or restarting engine does not change the behavior. But waiting approx 1 hour to cool engine down, it starts up fine, engine ok – nothing wrong, but then after ½-1 hour of driving the whole story repeats!
Please help!
P2050 Misfiring,damages TWC P0300Lamp&Stored&Current
P2057 Misfiring of cylinder 7,damages TWC P0307Lamp&Stored&Current
P2058 Misfiring of cylinder 11,damages TWC P0311Lamp&Stored&Current
P2059 Misfiring of cylinder 9,damages TWC P0309Lamp&Stored&Current
C1A00 ?
C1B00 ?
C1C00 ?
U3400 ?
P2043 Misfiring P0300Lamp&Stored&Current
Does a V12 have two crank position sensors? If so, one bank may be bad.
C codes are chassis codes.
U codes are CAN or BUS codes.
None of them are on my lists.
Best to be visiting your local dealer.
I’ve done some measurements on the ECI system - output from ECI power supply (before the coil pack).
Then the fault are present (left bank of cylinders not running correctly) the 180V and 23V output from the ECI-Power supply to the left coil pack is missing. When engine runs normally (after approx one hour switch off), the 180V and 23V are back on!
This should indicate a bad ECI power supply, but I don’t know if the ECU tells the ECI-power supply to shot down?
StarDiag tester showed the same error codes as my EU702 tester did!
Next move is a new coil for the left cyl. bank!
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StarDiag tester showed the same error codes as my EU702 tester did!
Next move is a new coil for the left cyl. bank!
If you swapped the wiring and it still says left coil then it's the ECI, if it was the coil then it would now say the right coil is faulty.
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Found part no. for the coil packs A2751500480 (right) and A2751500580 (Left)!




