Help! Need a PCM or repair

[thejeepgod]

Sounds like there could be a few things going on here.

1) From reading back to the beginning it sounds like the jeep ran when you brought it in for a wiring issue. Something odd must have happened during the wiring fix for the original pcm to die, this is weird.

2) You should get a straight answer out of him - What was the p/n for the original pcm, 492 or 493?

3) If you have tried 3 different PCMs both 493 and 492 it sounds like the problem is most likely not with the pcms.

4) Is there physically a leak detection pump in the jeep? It the original pcm was a 493, then there should have been. What happened to it? Even then, if you plug the 492 in, it should not be looking for a leak detection pump and the light should not be on whether the leak detection pump is physically there or not.

The original cause was a wiring harness issue. It sounds like that while the wiring harness was being fixed for the other issues, something else got messed up inside there. The best/easiest fix might be to swap in a new, known good wiring harness though this current guy might not be the best one to do it.

 

[Wayne Sihler]

This may not be correct,as I,m looking at a 96 FSM...BUT could what you are calling a "leak detection pump" be the EVAP canister purge solenoid ?
I dont know where its located on a 99. On my 98 its located by the heater hoses and AC lines on PS of firewall.
Or if you need to sell------ i might be interested.we have on emissions test out here

 

[N8N_99xj]

Sounds like there could be a few things going on here.

1) From reading back to the beginning it sounds like the jeep ran when you brought it in for a wiring issue. Something odd must have happened during the wiring fix for the original pcm to die, this is weird.

2) You should get a straight answer out of him - What was the p/n for the original pcm, 492 or 493?

3) If you have tried 3 different PCMs both 493 and 492 it sounds like the problem is most likely not with the pcms.

4) Is there physically a leak detection pump in the jeep? It the original pcm was a 493, then there should have been. What happened to it? Even then, if you plug the 492 in, it should not be looking for a leak detection pump and the light should not be on whether the leak detection pump is physically there or not.

The original cause was a wiring harness issue. It sounds like that while the wiring harness was being fixed for the other issues, something else got messed up inside there. The best/easiest fix might be to swap in a new, known good wiring harness though this current guy might not be the best one to do it.

AFAIK from talking to him the last time the original PCM was a 493.

There isn't and doesn't appear to have ever been a leak detection pump.

I really don't have the ability to swap the harness nor source of same. I'm dealing with a full time job plus dealing with a SO with serious medical issues, the only work space I have would be borrowing lift time at my buddy's shop in the hood which is almost as far away from me as the shop it's at, and my free time is almost nonexistent. (I know it sounds like I'm whining but really I'm just laying out the situation.)

This is supposedly the "go to" shop for electrical issues in the metro DC area.

I'm pretty much lost at this point...