[RafalZajac]

Hi everyone, I'm new to the forum. However, I have a problem with my 2019 Camaro 2.0 T.
I decided to replace the spark plug at 35,000 miles.
I used NGK replacements and unfortunately, they had a 1.2mm spark gap instead of 0.9mm, which made no difference at idle, but at high RPM, I experienced a misfire problem on the cylinders.
I went back to the old spark plugs and the problem disappeared, but only for a short time. After driving 40 miles, it reappeared and cylinder 4 completely misfired. I swapped the coil and spark plugs with cylinder 3, and unfortunately, the problem isn't with the coil or cylinder.
Does anyone have a wiring diagram for the ignition system? I suspect something on the low-voltage side has failed.

[bishopts]

Originally Posted by RafalZajac

Hi everyone, I'm new to the forum. However, I have a problem with my 2019 Camaro 2.0 T.
I decided to replace the spark plug at 35,000 miles.
I used NGK replacements and unfortunately, they had a 1.2mm spark gap instead of 0.9mm, which made no difference at idle, but at high RPM, I experienced a misfire problem on the cylinders.
I went back to the old spark plugs and the problem disappeared, but only for a short time. After driving 40 miles, it reappeared and cylinder 4 completely misfired. I swapped the coil and spark plugs with cylinder 3, and unfortunately, the problem isn't with the coil or cylinder.
Does anyone have a wiring diagram for the ignition system? I suspect something on the low-voltage side has failed.

You don't want to suspect an injector?
If you have a problem with the wiring to the coils you're going to have a circuit fault code for that coil.

[RafalZajac]

258
They appeared. First P0300, then P0304, P0354, P050D. Unfortunately, I only have a Delphi diagnostic tool and can't clear them. I already bought VXDIAG for the Chevy, so I'll try today, but I need an electrical wiring diagram because it's hard to find the cables without one.

[RafalZajac]

The 6th generation Camaro was never sold in Europe so I have very limited access to documentation.

[bishopts]

Recheck your spark plugs. Use the new ones and gap them to the correct specifications. Visually check the porcelain to make sure you didn't crack them when they were installed. Check the connectors for the coils, i have a lot of them that the rubber insulation in the plug will bind when plugging in and it will keep the connector from plugging all the way in. I use dielectric grease as a lube on most any plug that i unplug.

I will try and get you a diagram later today or possibly tomorrow.

[bishopts]

ignition feed is from one fuse labeled
coil odd fuse
wire color is purple\blue and all coils have that wire

the Black\Blue wires they all share are low reference which is pcm ground
the pcm side of that is connector X2 cavity 44

yellow\blue is the coil control wire for cylinder 4
pcm X2 cavity 66

[SnoZi]

Hello everyone, I'm also new here. nice to meet y'all !

Could you tell me you if you eventualy found a solution for your problem ?If yes, what was it. @RafalZajac

And for anyone willing to help on my current situation, here is what going on pretty much :

Initial issue:

Ignition coil connector (cyl 4) got burnt, likely from a failing coil zzp highV
Started with intermittent misfire on cylinder 4
Wiggling the wiring near the connector would temporarily fix the misfire

Codes observed:

P0354 (Ignition Coil D Control Circuit)
P0300 previously (random misfire)
StabiliTrak warning appears when misfire is active

Work done so far:

Replaced ignition coil (multiple swaps tested, no change)
Replaced spark plugs
Repaired coil connector:
New connector housing
New pins properly crimped
~15 cm of new 0.75 mm² wire added
Verified:
12V supply at coil = OK
Ground = OK

Current situation:

Constant misfire on cylinder 4 (no longer intermittent)
P0354 comes back immediately
No change when wiggling wiring anymore
Engine runs on 3 cylinders (cold worse, slightly better warm but still misfiring)


Im planning to verify continuity of the trigger and feedback wires based on that diagram another user posted, THANK YOU very much for that by the way.

Other then that i ran out of solutions, please help.
Kind regards

[bishopts]

Originally Posted by SnoZi

Hello everyone, I'm also new here. nice to meet y'all !

Could you tell me you if you eventualy found a solution for your problem ?If yes, what was it. @RafalZajac

And for anyone willing to help on my current situation, here is what going on pretty much :

Initial issue:

Ignition coil connector (cyl 4) got burnt, likely from a failing coil zzp highV
Started with intermittent misfire on cylinder 4
Wiggling the wiring near the connector would temporarily fix the misfire

Codes observed:

P0354 (Ignition Coil D Control Circuit)
P0300 previously (random misfire)
StabiliTrak warning appears when misfire is active

Work done so far:

Replaced ignition coil (multiple swaps tested, no change)
Replaced spark plugs
Repaired coil connector:
New connector housing
New pins properly crimped
~15 cm of new 0.75 mm² wire added
Verified:
12V supply at coil = OK
Ground = OK

Current situation:

Constant misfire on cylinder 4 (no longer intermittent)
P0354 comes back immediately
No change when wiggling wiring anymore
Engine runs on 3 cylinders (cold worse, slightly better warm but still misfiring)


Im planning to verify continuity of the trigger and feedback wires based on that diagram another user posted, THANK YOU very much for that by the way.

Other then that i ran out of solutions, please help.
Kind regards

Definitely could have destroyed the coil driver in the ECM.
I haven't seen that in a while but it is a thing.

[SnoZi]

Originally Posted by bishopts

Definitely could have destroyed the coil driver in the ECM.
I haven't seen that in a while but it is a thing.

Hello friend, thx for the answer.

Altough i must ask
Did you use chat gpt to get that answer ? Or is that from experience ?
How do I know if it is the ECU?
If it turns out to be the driver. Can i repare this ?

Kind regards

[arpad_m]

Originally Posted by SnoZi

Hello friend, thx for the answer.

Altough i must ask
Did you use chat gpt to get that answer ? Or is that from experience ?
How do I know if it is the ECU?
If it turns out to be the driver. Can i repare this ?

Kind regards

bishopts is a professional mechanic who kindly sacrifices some of his time to help us all out here.

If that is indeed the problem, the ECM may be toast and you'll need a replacement. Let me attach the troubleshooting procedure from the service manual for you. At first glance it appears to agree with the diagnosis, but there are many steps to verify the condition.

I suggest that if your diagnostics indicate the need for ECM (K20) replacement, and you aren't able to get to a GM dealership, which may well be the case in Belgium, get a 3-day ACDelco TDS subscription and download the entire service manual (or get it from somewhere else), there's a whole host of additional information about the process.

[bishopts]

Coil primary circuits are pretty simple circuits.
The coil is charged by applying power to one end and ground to the other. The wound wires create a magnetic field, break the circuit and the field collapses in the form of a high voltage discharge into the steel bar in the middle of the winding, which is where your spark plug wire attaches.
So the fusebox supplies the power in. Its going to be key hot and shared with the whole bank. Meaning if that fuse is bad then all 4 on that side will be dead.
Ground is suppled by the PCM. Its coil driver is an internal trigger mechanism. Simply connect to charge the coil and disconnect to fire the coil.
Since you dont have 4 dead coils it's not the fuse.
Since you don't have a dead vehicle its not the PCM ground.
It leaves you with power wire from the fusebox to the coil, trigger wire from the coil to the PCM, or the terminals at any of those connections to test. If all of them are good then your coil driver has failed and you need a PCM.

Very simple to test. Go to the point of connection at the pcm for the trigger wire. Key on engine off you will have battery voltage. That will test all of the wires and terminals in that circuit from the fuse.

If you don't have power there then look for power at the coil, both wires should have power. If one does and the other doesn't the coil is shorted or you have a broken connection in the connector.

Since you have replaced the connector. Double check your splices and make sure they have continuity. Dont twist wires together and tape them. Solder and heat shrink is easy and better.

[SnoZi]

Originally Posted by bishopts

Coil primary circuits are pretty simple circuits.
The coil is charged by applying power to one end and ground to the other. The wound wires create a magnetic field, break the circuit and the field collapses in the form of a high voltage discharge into the steel bar in the middle of the winding, which is where your spark plug wire attaches.
So the fusebox supplies the power in. Its going to be key hot and shared with the whole bank. Meaning if that fuse is bad then all 4 on that side will be dead.
Ground is suppled by the PCM. Its coil driver is an internal trigger mechanism. Simply connect to charge the coil and disconnect to fire the coil.
Since you dont have 4 dead coils it's not the fuse.
Since you don't have a dead vehicle its not the PCM ground.
It leaves you with power wire from the fusebox to the coil, trigger wire from the coil to the PCM, or the terminals at any of those connections to test. If all of them are good then your coil driver has failed and you need a PCM.

Very simple to test. Go to the point of connection at the pcm for the trigger wire. Key on engine off you will have battery voltage. That will test all of the wires and terminals in that circuit from the fuse.

If you don't have power there then look for power at the coil, both wires should have power. If one does and the other doesn't the coil is shorted or you have a broken connection in the connector.

Since you have replaced the connector. Double check your splices and make sure they have continuity. Dont twist wires together and tape them. Solder and heat shrink is easy and better.

Hi,

I must say I'm very grateful for you guys's time and effort into my case.
I appriciate it very much.

I did indeed solder the wires then insulated them with heat shrink and then tsl tape then back in the harness's plastic conduit. I do have 12V and Ground checked , So it does points to the ecm circuit.
To me, the best guest would have been the wires deeper in the harness because before it went complete bonkers, wiggling and heating the wires close to the coil (the last 15cm that I replaced (+the connectors and pins)) kinda outed the core ecm, but as you know my knowledge in elec is quite limited so I guess I'm probably wrong. Today is the day my mechanic finaly looks into it so hopefully we'll have more answers on what to do.
I saw ROCKAUTO selling ECM for around 200 euros, Or I think zzp also sell some, Whom I might ask to send directly or at least discount but mostly they'll flash it. All the mess because of 1 coil internaly shorted somehow, What a mess.

Thanks again guys for your inputs and documentations.

Kind regards.

[SnoZi]

Hey guys,

So here is a little update.
I had a bunch of poeple to help, some guy with good knowledge ok electric tested my harness and all seems good
So I wen't for the ECU, brought it to a repair guy, He ended up finding (that he said though idk how trusted he can ben tbh) that the coil driver was indeed dead , but he couldn't get the components to repair. So I bought the 12700116 ECU from Amazon and had it cloned.
When I installed it :
Plugged it in
Plugged the battery back
Looked for codes before starting.
And I had a code saying : No communication with the ECM.
When the car battery is on now the ECM relay in the fuse box goes crazy clic clic clic clic.
I thought something was wrong with sole fuse or relay but when I tryed with the old ECU it had no problems (besides the obvious coil driver thing).

So now I have no idea what is wrong, is it the clone that is bad ? Am I that unlucky and I got a defective ECU ? Is there something else to do for the car to accept the new ECU ?
I'm so lost and mad with this whole thing its getting crazy.

Kind regards

[bishopts]

Originally Posted by SnoZi

Hey guys,

So here is a little update.
I had a bunch of poeple to help, some guy with good knowledge ok electric tested my harness and all seems good
So I wen't for the ECU, brought it to a repair guy, He ended up finding (that he said though idk how trusted he can ben tbh) that the coil driver was indeed dead , but he couldn't get the components to repair. So I bought the 12700116 ECU from Amazon and had it cloned.
When I installed it :
Plugged it in
Plugged the battery back
Looked for codes before starting.
And I had a code saying : No communication with the ECM.
When the car battery is on now the ECM relay in the fuse box goes crazy clic clic clic clic.
I thought something was wrong with sole fuse or relay but when I tryed with the old ECU it had no problems (besides the obvious coil driver thing).

So now I have no idea what is wrong, is it the clone that is bad ? Am I that unlucky and I got a defective ECU ? Is there something else to do for the car to accept the new ECU ?
I'm so lost and mad with this whole thing its getting crazy.

Kind regards

You have to program the ecm to the car. Its not something you can just get and plug in.