Update on PCM gone Loco

raymondk · #1 (**permalink**) 07-16-05, 12:17 AM

After hours of looking for wiring problems I dropped the PCM down in order to get the numbers for a replacement. Just for spite I tried to start it and it started and ran perfectly. After clearing all codes and repositioning the PCM I drove it about 75 miles and then a PO52 (memory keep alive) popped up along with stumbling and a "traction dissabled" I haven't found the problem yet but moving the PCM makes it look like a connection on 2c4 or 2d4. It could still be the PCM but I doubt it.

sts96 · #2 (**permalink**) 07-16-05, 09:38 AM

Ihad a problem with a pcm connector that had been checked by someone before I found it, looked like it had been damaged (opened up) by a probe. gentle removal fron the socket body and restoration of shape solved the problem. sts96

BeelzeBob · #3 (**permalink**) 07-18-05, 12:32 AM

Did you try tapping the PCM not so gently to see if that makes a difference as to when it acts up...???

raymondk · #4 (**permalink**) 07-19-05, 08:21 PM

I tapped and wiggled but not violently. It is still doing the same. It happens on smooth roads at any speed. It appears to start with a buck and a traction dissabled message with a TO73. Then a PO36 more often. I've had the EGR valve off several times and found no sign of a problem. The EGR ports are all clean. Temperature seems to have no effect, and running accessories doesn't either. I have a 200 mile trip tommorrow so maybe I can find something.

raymondk · #5 (**permalink**) 10-22-05, 01:06 PM

Well my 200 mile trip lasted less than 5 minutes. After packing up, I made it to the end of the drive, then back to normal; a string of codes and engine quit. After exhaustive tests the main fault appeared to be no voltage to the PCM when it was really there. The engine feedbacks appeared to work properly but the display showed no feedback at all. Replaced the PCM with a Cardone unit, started and ran perfectly but imediately threw a PD76 (i believe) transmission pressure solenoid failure. It jerked and shifted at odd times, and after reset would work fine for a minute or two then fault again. I managed to get it running with the old PCM and the transmission did perfect (till it quit). More testing then I made a warranty claim and they sent me another one imediately. It appears to be perfect now but my test run was cut short by a core plug blowout.