Hi All
I am currently tearing my hair out with a set of error codes with my 97 xk8 (see my posts)
To summarise ;
The 5 codes are
P0351
P0354
P0356
P0357
These 4 codes relate to the ignition coil linked to one of the two ingnition modules
P1367
This a ignition control module
My car defaults to 'limp home mode' after starting an running normally from cold for a couple of minutes. If the car is restarted with a warmer motor the time till 'limp home mode' reduces.
The transition from normal running to yellow light, limp home is instantaneous.
Engine scanning gives identical codes to what you are getting.
I have eliminated the 4 ignition coil codes by swapping the coils into the good positions. This gives no change in the error codes indicating the problem is not with the coils ( also checked all coil impedances and they all indicate 1.2 ohms)
I have swapped the ignition modules, once again no change in the codes
I can't believe that it is the ignition relay as from studying the wiring diagram any failure of the relay would have to affect both modules
I have checked all multipin connectors
I have looked at the large junction on the firewall behind the throttle body.
I just don't know where to go next
It may be a broken wire but everything looks rather pristine in the engine bay
It may be an engine control unit, no way I know of testing it.
Any help greatly appreciated
Regards
Alan

 

Reset the codes and recheck them quickly to see if one code comes in first. If that is the case swap that coil, and see if the code that comes in first follows that coil. If so, just replace that single coil.

Certain coil failure modes can cause misfires to register on good coils, but the true bad coil registers the fault first.