Hey guys, first post here.

I have a 2004 Grand Cherokee Overland with the 4.7L HO V8. I have been told that I likely have a bad PCM, and I would like to replace it myself. I found a place in Florida that sells refurbished PCM's, and will even program it to the VIN and mileage.

I have done some research online, and it seems pretty easy. From looking under the hood, and reading a few posts on other forums, I am still unsure of where it is located. I see two modules, one behind the coolant overflow tank, and one next to it. Anyone know by chance which of the two it is? I'm sure I could figure it out once I get the actual part, but I figured that I would get a head start taking the bad one out.

Any other tips for installation?

Thanks everyone. Looking forward to participating in the great forums here.

 

Figured I would give a little more background to see if there is anything else I can try.

I replaced the PCM in march of 09 at around 92K miles. At the time, the car was idling roughly, as well as experiencing sluggish acceleration. I had it replaced at the dealer (big mistake), and it ended up costing me $800. Anyhow, it did resolve the problem.

Even though the new PCM fixed the problem, the check engine light came back on a few days later. The dealer ran the codes and said that it could be the catalytic convertor or the O2 sensor. The car continued to function normally. Since I didn't notice a drop in fuel economy, and my state does not have emissions testing, I decided not to look into it further.

Now this last week, my Jeep began to have the same problem that I was experiencing lsat year. It idles roughly, as well as exhibiting sluggish acceleration. Now the check engine light blinks on occasion as well. I took it to a local mechanic this time, and the codes PO352 and PO302 come up. Cylinder 2 is currently misfiring. They swapped the #2 coil with the #4 coil, and the cylinder continued to misfire, thus their recommendation to swap out the PCM. He said he could do it, but that I could save a lot of money if I order one online and do it myself, which is not very technically challenging.

Any of you experienced persons have any advice? Does it sound plausible that this PCM is bad?

I did forget to mention something weird that happened. When this all started, I was driving and needed fuel. I wasn't planning on taking it in right away because I had no time to get another vehicle for work. So I decided to fill it up (it had about a 1/4 tank). When I refueled, I noticed the rough idle and acceleration problems did go away, until I had a 1/4-1/2 tank left, then the same problems returned. I tried filling it up again, but this time no such luck.

I might try some Seafoam and see what happens in the meantime. Thanks.

 

First let me say Welcome to CF!
This linkshows where the Modules are located. Click the pic to enlarge. http://www.wjjeeps.com/modules.htm
This tells you how to retrieve the codes yourself, and what they are. Scroll down for the codes. http://www.wjjeeps.com/faultcodes.htm#ERASE

 

lol i sent mine to FLorida cost me 85 bucks to diagnose it and 205 to fix it if it is broken, i fist sent my TCM haha and then my PCM lets hope this will fix my starting problem