Cherokeesun

I need an engine control module for my mom's '91 Cherokee with 4.0 motor, 4-speed overdrive/4WD. What years will work on this vehicle? I'm assuming I need to get one that is programmed to work with the same tranny, right? Is the PCM the same thing as a ECM? Anything else I need to be aware of when replacing the ECM with a used unit? Thanks in advance.

jeepfreak82

The biggest thing would be to be sure if you have the H.O. motor or not as this would indicate a Chrysler system, which you should have. I believe that the computers are mostly the same up to 95 as long as it is spec'ed out the same way as yours.

Cherokeesun

Thanks jf82. Pretty sure the motor is not the H.O. version. I found a used module off a running '91 Cherokee with the same motor/tranny combo yesterday and the guy's willing to sell it for $50. Crossing my fingers and hoping it fixes my mom's Jeep.

OverlandZJ

There will be a number on the computer, see if it matches.

ECM, ECU, PCM, PCU all mean the same thing. The transmission has it's own computer and is called a TCU.

Cherokeesun

Follow up question: how would I know if I have the H.O. version or not?

Cherokeesun

Okay, gotcha Overland XJ (posted that last response before I saw yours). I'll check the numbers. Thanks.