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What a mess! Started with a no start condition and a ton of internal codes and no data communication. Found a corroded pcm and even worse, the wire harness which doesn't look usable anymore just because of the pins in there.
The BCM seems to be ok with all of the PIN 2 voltage checks and star connectors, however still no comms there either.
So here is the question...just a little bit of searching, but have any of you sent a PCM for inspection or refurbishing? It's for a friend of mine, so before we just buy a new one, curious if this is saveable.
Also check out the tails of the harness...def no good...I'd be interested to hear anyones recommendations on where to get a replacement...maybe ebay?
A new harness is sounding like a real pain but is what it is
Thanks, yea this is a real mess. I found plenty of PCM's around that are refurbished, etc...pricey but no big deal. Finding a nice harness might be a thing...gosh I am just not looking forward to doing that part...but hopefully this does the trick!
Only thing not working in the car even with all this was the turn signal indicators in the cluster, and the blower motor..which is good, as well as the relay and module. Only getting 1 volt to each leg on that harness...the red wire there was 12 volt..maybe that's a whole separate issue in the hvac controls.
wow that's a huge help! tedious, but its cost effective. It looks like only a few pins were eroded, I will de pin each one, inspect and put in the new connector...hopefully not on my back. I got a lead on a rebuild service too. Davies Corvette parts in Florida in case anyone else comes across this.
Oof, thats nasty... Try cleaning everything with white vinegar and a soft bristle brush.Everything needs a sodium bicarbonate/distilled water mix to neutralize that mess.
I was going to attempt some cleaning, the pcm looks like it can be cleaned, but those harness pins..If you look, most of one side of the red connector casing is eaten away. As much as I don't want to, it looks like maybe getting the connectors and re pinning them is the way to go. Hoping I can pull out some slack to work comfortably.
It's a friends car, sitting for a couple years because of the no start. I just found out it about it. Tracking down electrical gremlins led me to there after I decided the BCM was likely fine...while I didn't see a connection between the blinker dash lights and the blower motor lack of power linked to the PCM, maybe it is somewhere
I have only seen one that corroded once before, and it was a flood car. Based on the limited pics, and the condition of that rotor alone, I would say this car has spent some time in water......or it has been sitting for a long time somewhere outside unprotected. I have feeling you are in for a serious challenge.
I have only seen one that corroded once before, and it was a flood car. Based on the limited pics, and the condition of that rotor alone, I would say this car has spent some time in water......or it has been sitting for a long time somewhere outside unprotected. I have feeling you are in for a serious challenge.
Oh, well I mean...it could have been a flood car, but it has just been sitting for over 2 years now...northeast weather...The rest of the car is actually in good shape. It has an acid smell to me and there is evidence that the fender was slightly moved before to likely clean it before my friend got the car. He did drive it for a couple years before the problem occured. It likely sat, had a battery leak, last guy cleaned it and traded it to my friend for work done.
I have found a lot of harnesses out there. It just needs the PCM and they are about 500-600. Would you just re pin it with new connectors or tackle trying to get the harness out? Have to do like 100 pins
Oh, well I mean...it could have been a flood car, but it has just been sitting for over 2 years now...northeast weather..
You REALLY need to know this. If the water even got up to the floorboards, it will never be right. I would be pulling it apart looking at strategic areas before I turned a wrench or spent a dollar on that car.
Pull back carpet. Inspect blower fan / BCM area and IPC fusebox. Get car on a lift and see how bad corrosion really is. Drain fluids and assess condition..plus all ground locations and splice packs.
I wish you luck
Last edited by lucky131969; Nov 18, 2024 at 12:38 PM.
You REALLY need to know this. If the water even got up to the floorboards, it will never be right. I would be pulling it apart looking at strategic areas before I turned a wrench or spent a dollar on that car.
Pull back carpet. Inspect blower fan / BCM area and IPC fusebox. Get car on a lift and see how bad corrosion really is. Drain fluids and assess condition..plus all ground locations and splice packs.
I wish you luck
Thanks bud!
Yea everything inside looks great no signs of water. All the grounds are perfect, BCM is good by my tests, though it's not seeing comms likely due to the PCM. No idea whats up w the blower. It has 6 wires, 12v comes in on the red, the orange is supposed to have power all the time but only sends 1 volt. same is on all the others. Maybe I will take the center console and see what's up there. I would assume each leg is supposed to send 12 volts when its speed is selected, and the module steps it up or down. That's for another day.
I have cleaned grounds and the ignition switch but thankfully we have not had to go into the pins of the ECU. A friend and I recently replaced a ECU and fingers crossed the problem stays fixed.
I ran across this, you maybe interested in the 20min mark and part 3 of their journey. The car is still running.
Wasn't the 98 the year, or one of the years, they had the Delco batteries leak down on the PCM?
This may be why you are seeing what you are seeing. Good luck regardless, that's a mess you got there. Although may be some just pins need to be replaced and a new PCM, like you said?
Wasn't the 98 the year, or one of the years, they had the Delco batteries leak down on the PCM?
This may be why you are seeing what you are seeing. Good luck regardless, that's a mess you got there. Although may be some just pins need to be replaced and a new PCM, like you said?
It was a problem IIRC with the battery used in early C5s and later batteries were improved.
However, as C5s are now 20+ years old it could have happened with a replacement battery. The battery placement did not change between any of the C5s. Some C5s did get AGM batteries and there was debate over life span of using a lead acid battery in a AGM car.
It is possible the damage was caused by a leaking battery and not a flood. A friend and I have been bringing back to life a late C5 that sat for a decade and have replaced the ECU and a battery might have caused some damage.
Corroded PCM
