PCM Blues, 2 Different 'Reman' Units Failed within an Hour of Installing - Ideas?

dimanche 22 juin 2014

Let me start at the beginning, for years I have running my '00 4.7 with a perpetual P0443 EVAP Solenoid code - to the point that my CEL bulb died and I though it was corrected after I changed the solenoid.



Fast forward a few years and I failed emissions inspection in NY (the Jeep had been sitting around for a while, I rehabbed it, registered and insured it then went for safety and emissions inspection and failed the emissions).



Over the last year I have been trying to get to the bottom of the CEL code and replaced every EVAP hose, connector, gas cap, and even the LDC pump. The conclusion was that something isn't right with the PCM and it needs to be replaced.



I took a gamble on a Reman unit from those shady charterers in FL (off eBay) and got a franken-PCM, it looked butchered (see pix) but I took a chance and installed it. The Jeep started up just fine, ran nice, idled better then it has in a while and most importantly, I felt the EVAP solenoid working!



Problem solved, right? WRONG!



After letting it run for nearly a half hour I shut it down and an hour later took a half hour drive. Along the way the engine stumbled once and shut down and started right back up after throwing it in neutral and turning the key.



Continued to my destination (Costco) parked and went shopping. About 45 minutes later I went back to the Jeep and tried starting it up. Off the bat I noticed something not right, the gauges did not come to life like they usually do - gas stayed flat, same for voltage and temp and most disturbing was no light from the CEL, just the immobilizer light and the check gauges light lit up.



I knew right away that the PCM and the rest of the Jeep weren't talking, so for the heck of it I tried cranking it and it did turn over but did not start.



Called my wife, had her bring the old PCM and my tools over and switched the old PCM in and it started right up and drove home. Needless to say that the CEL with my old P0443 came right back.



Called the FL company and they said they would take the PCM back and refund, asked if I wanted a replacement I said no thank you and went on searching for a new PCM.



I heard some good things about the Reman PCMs from A1 Cardone, so I bit the bullet and ordered one ($341) through AutoZone. Gave them my VIN and mileage and got the new unit on Friday.



Off the bat this unit felt right, looked good and not butchered. All excited, I went and installed right away.



And the problems started again!



After letting it run for 5 minutes the engine stumbled and shut down, I restarted it and it ran for another minute and shut down again and this time there same thing that happened in the Costco parking lot happened again. No communication with the PCM.



Frustrated I left it over the weekend and brooded... Then this morning I figured 'what the hell' and tried starting it and lo-and-behold it started!



Now I am left scratching my head, what the hell happened? Obviously the new unit is not the problem, and I wonder if the FL PCM was really bad to begin with - or if the Jeep ate it...



So any thoughts? Is there a 'safe mode' which is shutting down the PCM to protect it? Something else?




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