My 2003 EB Z06 has 65k miles and is bone stock other than a Vararam intake. The car has never given me any major problems up until now...

I consider myself mechanically inclined, however on the electrical side I am a bit in the dark.

Over the past few months I've been throwing P0357 - "Ignition coil #7 circuit" I have done the typical things to diagnose the problem however the solution still evades me. I should also mention that this code is intermittent and can not be reproduced on command. Over the past few weeks it seems to be occurring in greater frequency. There is no noticeable difference in performance with the code active or when everything is temporarily OK. I have also noticed a slight "pinging" sound from under the dash (only occasionally at high WOT RPM's), but I'm willing to bet this is my throw out bearing telling me to replace it. I am mentioning this because it could very well be a ping from a bad coil circuit BUT if this were the case, why would I not get a misfire or knock code??

I have done the following to troubleshoot thus far:

-Swap Coil banks (code did not follow, still P0357)
-Swap plugs and wires from #3 and #7 (code did not follow, still P0357)
-New plugs and wires (old plugs looked OK. #7 was slightly darker than others)
-I have checked coil harnesses/pins for spread female ends and chaffing/rubbing.

It was mentioned here that the harness might rub on the fuel rail. My harness does show a small amount of rubbing, however was not able to locate a tear or break in the harness. Wiggling the harness does not replicate the code nor help my situation.

In doing these things I'm lead to believe that the problem is further up in the circuit, either a bad harness or PCM.

I was able to find this post that explains how to troubleshoot my code, however its in spanglish to me!! Can you or someone put this into laymens terms? I have a cheap DMM that I would love to use to check the continuity of the harness and the PCM, but have no clue where to start or what pins/locations to check.

I apologize if I omitted any important information questions/advise welcome!

I really don't want to take this into the stealership to fix so I'm at the forums mercy!

Thanks!!

 

send Bill Curlee a pm, he's a genious when it comes to the electrical problems.

 

Thanks I'll do that!

 

Bill has been great in helping me start to diagnose the problem. Anybody else run into something similar that might help me find the culprit?