[rlarsen462]

Originally Posted by Alain

are you aware of the TSB put out by GM for part of the wiring harness rubbing against the metal in the engine bay causing it to fray?

this might be what you are experiencing. maybe the relay wasn't bad but your wiring harness has been compromised from rubbing on the metal and that's what's messing with your ECU.

check around here, the TSB's were posted on a thread. I thought I had them saved on my phone but I don't anymore.

worth a look.

Definitely heard of it but none of them apply to 2019's right? And the assumption being those fixes are applied to 2019 and later cars?

I feel like if the harness was frayed I would have way bigger operational issues with the car then a random CEL about a slow ECM circuit startup... The car runs perfectly including at the track... But I admit I am running out of possible explanations.

[DangerZL1]

It shouldn’t be your problem. It may be time to take it to the dealer. I wouldn’t want to either, but without access to scan tools and GM tech you’re at a loss. Keep us posted. Maybe it’s an easy fix

[Alain]

Originally Posted by rlarsen462

Definitely heard of it but none of them apply to 2019's right? And the assumption being those fixes are applied to 2019 and later cars?

I feel like if the harness was frayed I would have way bigger operational issues with the car then a random CEL about a slow ECM circuit startup... The car runs perfectly including at the track... But I admit I am running out of possible explanations.

It's supposed to have been addressed for the 2019 model year......... but you know how that goes.

I would still consider it a possibility even though your reasoning that you probably would be having bigger issues if the wiring harness was frayed is a good one.

It would drive me insane if I had to keep dealing with this phantom issue like you have.

I don't want ANY dealership touching my car unless I absolutely have to. With that being said, I would bring it to my dealership and have them scan it with their diagnostic tool and see if they can find something else that you are missing with yours scanning tool.

that's the only thing I would let a dealership do to my car since it doesn't require any lifting or jacking the car and they don't have to take anything off the car to diagnose it.

Please keep us posted, i'm sure at some point someone is going to have a similar issue.

[rlarsen462]

At this point according to the diagnostic (from service manual) guide that I have it's either the fuse block itself or the ECM/ECU...if the latter I really don't have a choice but to let them warranty since that's probably like a $3K part...

I'm going to make some calls to dealership service departments this week and see if I can find one that gives me a good vibe.

[rlarsen462]

FYI since I've been posting about it in a different thread, I suspect it may be the Gen5DIY radar detector harness (as it actually inserts in the ECU wiring path to power the RD with factory style connectors). I have the updated 2019 one with the capacitor to prevent RD dropouts when traction control engages.

I unplugged the harness for the last week or so and haven't seen the code come back yet, but I'm going to put it through it's paces a bit more before calling it the culprit and seeing what Gen5DIY has to say about it.

[angryBits]

Originally Posted by rlarsen462

FYI since I've been posting about it in a different thread, I suspect it may be the Gen5DIY radar detector harness (as it actually inserts in the ECU wiring path to power the RD with factory style connectors). I have the updated 2019 one with the capacitor to prevent RD dropouts when traction control engages.

I unplugged the harness for the last week or so and haven't seen the code come back yet, but I'm going to put it through it's paces a bit more before calling it the culprit and seeing what Gen5DIY has to say about it.

Excellent! That sounds like a very likely culprit. Glad you found it!

[Alain]

That’s sounds like the the fix !!! This is why I hesitate tapping into the car’s wiring harness for any reason.

[CodemanZLE]

I just started getting this same code thrown a few days after installing the Gen5DIY harness as well. Now that it’s been a little time, did removing it seem to fix your issue?

I had also installed an nGauge, so that may also be a culprit. Currently experimenting with both.

[rlarsen462]

Originally Posted by CodemanZLE

I just started getting this same code thrown a few days after installing the Gen5DIY harness as well. Now that it’s been a little time, did removing it seem to fix your issue?

I had also installed an nGauge, so that may also be a culprit. Currently experimenting with both.

Check out this thread, Gen5DIY themselves respond:

https://www.camaro6.com/forums/showthread.php?t=556584

Long story short, yes the harness is causing codes, they are now aware of it (pretty sure myself and the other guys in that thread arrived at the idea at about the same time that it could be the harness and Gen5DIY had no way of knowing it was a problem until one of us brought it to their attention), and I have a replacement harness they are sure will fix the issue en route for testing.

I have nothing but good things to say about Gen5DIY, they stand behind this product and respond almost immediately to emails. This car is an absolute pain in the ass to hardwire in a RD properly and they are committed to getting their solution right.

Fingers crossed the new one is the solution. Problem was likely caused by the need to have a capacitor to prevent the RD from shutting off when traction control engaged. It freaked out the ignition/ECM startup circuit and triggered the P10E4 code.

[rlarsen462]

FYI got the new prototype harness in and so far so good, and no codes. Hopefully it holds up...this has been quite a ride!

[CodemanZLE]

Originally Posted by rlarsen462

FYI got the new prototype harness in and so far so good, and no codes. Hopefully it holds up...this has been quite a ride!

Great news, I’ll have to reach out for a replacement.