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Chased a couple codes a few months ago, ended up replacing the ECM. Codes all appeared to go away...
Few days later, I get a new one, code #55. I believe on this year CCC, that could be an ECM ground fault.
This is a new ECM, but I checked all the grounds going to connectors, cleaned them well, and thoroughly inspected. Additionally, I tried grounding the ECM case directly to battery ground post with a jumper wire. Code still did not go away.
Any other ideas? Could I really have gotten a new ECM that broke so soon after installation? It's only a couple months old...
Chased a couple codes a few months ago, ended up replacing the ECM. Codes all appeared to go away...
Few days later, I get a new one, code #55. I believe on this year CCC, that could be an ECM ground fault.
This is a new ECM, but I checked all the grounds going to connectors, cleaned them well, and thoroughly inspected. Additionally, I tried grounding the ECM case directly to battery ground post with a jumper wire. Code still did not go away.
Any other ideas? Could I really have gotten a new ECM that broke so soon after installation? It's only a couple months old...
To clear a trouble code you have to pull the fuse next to the battery for a minimum of 10 seconds. Merely fixing the problem does not clear the code.
DTC 55 is a code for an internal ECM fault. there are no diagnostic routines for this code. You can check all powers and grounds for the ECM but if they're all good, you'll have to replace it. Now, with that being said, years ago, used to see this code quite a bit, yet it had no effect on driveabilty. Go figure. Only thing that sucks is CEL will never go out and will always pop back on after ECM clearing. Man, if I had a nickle for every one of those old GM OBDI PCM's I replaced I could've retired years ago. Good luck.
If you did not spend some extra time using Q-tips and alcohol to clean ALL of the contact pins in the wiring plugs, you need to try that. Those pins/sockets get tarnished with age, too.
You are sure the chassis ground wiring is GOOD (internally at connector points?) and no new paint under connections?
If those ground items are clean, then the ECM is defective internally. Call vendor and discuss if that's what's wrong. That fault (if internal to the ECM) is unlikely to have been caused by you.
yes, on the connector cleaning. Used De-Ox it on all pins as well as a thorough inspection. everything looks good. All pins that should be grounds are indeed.
BUUUUT, there are a couple things i don't like.
1. the main battery ground cable has a secondary wire, with an old splice in it that is no longer termiated (see pic). Not sure if this is supposed to go anywhere, or if this is possibly an aftermarket cable, or something else funny...
2. There is a relay set, that has a bunch of wires cut on it... can anyone tell what this is supposed to do?
Ground cable looks like standard parts store replacement cable. Most of those have second have secondary ground lead. PCM memory power is fed directly from fuse box. 20amp BATT FUSE. Don't think it has the inline connector off of battery that GM used in some cars. AT any rate just undoing the battery will clear the memory. You could also undo both battery terminal and connect the POS and NEG terminals together with jumper wire for about 20 minutes. this will also power down the internal capacitors. Will make the PCM return to it's "like new settings".
02-03-2016, 09:53 AM
DTC 55, trouble code,CCC,1981 C3 corvette ECM/ECU "ground fault"???
