PCM question

What is causing you to replace the PCM? Typical PCM starter issues? Engine code light malfunction, bad idling, etc..? I know that the tranny's have to be the same - auto to auto or manual to manual. My PCM died in my automatic 1995 YJ 2.5L 4cyl and I couldn't for the life of me find a direct replacement. I put a PCM from a manual 94 2.5L 4cyl YJ and it wouldn't shift into 5th gear and had some low rpm idling issues. In the end I replaced the three main capacitors on the PCM circuit board and it fixed my problem - was told that those capacitors fail and cause 99.9% of the PCM burnouts in YJ's. There are great websites out there who you can mail the defective PCM to and they will test it and fix whatever's wrong with it and mail it back with lifetime warrantee. There are also all kinds of videos that can help guide you through a capacitor replacement -
- if you want to go down that road.
 
Should work fine. The XJ automatic has a separate TCM (transmission control module) for it's 4 speed electronic automatic. The 92 YJ automatic has no electronics so the XJ PCM should still work fine. IF it was a 94-95 YJ you were installing on, then you would have a problem because the XJ PCM would not be able to lock the 94-95 torque converter. 1992 doesn't have a lockup torque converter so it should be no issue.
 
Gilaguy23 said:
There you go, from the voice of probable been there, done that already ;)
Click to expand...
Hah! Haven't quite been there, or done that, but I'm using what I've learned to make heavily educated decisions. I would feel bad and apologize if he went through with it and it doesn't work. I've been trying to learn the differences between PCMs and what works with what. @SirDoopYJ confirmed for me that his 93 auto does not have a lockup torque converter. I also checked the 93 FSM and there was no mention of lockup at all, so obviously the computer isn't special since it's doesn't have to provide lockup. This also tells me that 92 doesn't lockup either, so the OP should not have lockup on his 92.

the XJs used the AW4 automatic which I know is electronic just by general internet knowledge and it has a TCM with a bunch of wires going to it which people always have to integrate to their YJ when they do an AW4 swap. I know for sure some people have taken XJ auto PCMs (since TCM is separate) and run their manual YJs with them. That tells me that I'm 99% sure you could run a non lockup auto with the XJ PCM because it would be the same as a manual YJ basically. Same reason why you can run any manual with an auto PCM and you can run any 93 or earlier auto with a manual PCM. The only special one is 94-95 auto because they need the lockup TCC signal, so if you have a 94-95 auto, you're kind of hosed.

They sure did sell tons of different PCM models and I'm not sure what all the differences are. There were 6-7 PCMs per model year it seems. Can't figure out why.
 
Ha, I had a 97 F250 with a 460/auto. The manual showed some 50 different calibration versions for that year truck with the 300/6 thru the 460 gas engine. Mind boggling trying to decipher emissions diagrams on some of them.That and in 170K miles it are 3 PCM's that had to be a like Cali code to pass smog or run correctly id imagine. I miss my old 6.9 Ferd F250. Was good for learning to be patient as it topped out at about 60 on flat ground. Only thing more gutless was a old diesel Jetta VW.
 
Call these guys for a complete go through with a lifetime guarantee......They hooked me up when my 2.5 went down.....
Cost me 100 bucks......Look for them on ebay........

card.jpg
 
Top Bottom