Lufthq

I just bought a 2000 V-8, Grand Cherokee yesterday. Guy said it had a problem about a year ago with it cutting out/won't start. He said it cuts out when it is very hot, but is fine in the cold. Took it out today and new tires, etc... and stopped off for a fast wash. After the underframe wash, she cut out and would not start. cranked like crazy but no fire. Let her sit w/hood open for 30 minates and she fired right up. Took her to my mech, and he said he had seen this Jeep before...... gave him the owners name and he was their mech also! Records show that in 2010 they had same problem, replaced the CPS, rewired the battery, etc... they think it is the Power Control Moduale/PCM, (local dealer also agreed with them), sent out the PCM to be reworked and it came back as no problem found. They were gonna replace the PCM, but in 2010 he said they could not find one, shortage of PCM's and many were looking for one at that time. Original owner decided to just park vehicle, until he sold it to me!

So here/now in 2012 does anybody have a good idea what may be going on here? Thanks for the help, Paul.

Lufthq

OK, I been doing some research and it seems I may be on the right track with the ECM/PCM. I see lots of ref. to the electronics being good, but the connections being faulty. Anybody else had this issue?
Seems the PCM is availible now but there is a big differance between "rebuilt" and "refurbished". And many saying stay away from any you may find in a junk/savage yard.
Anybody else had this issue or can offer advice?

Lufthq

PCM Update.
Remanufactured PCM's are about $800 from the dealer but about $130 from Advanced Auto! Are these the same just a big dealer mark up?
Also, there seems to be a common issue of running hot when these shut-offs happen. I was told that factory Jeep thermostats are set at around 195 to 200 deg. and that after market ones can be found for 165 to 180 degs. Also, this PCM is mounted on the firewall with the Radiator reserv right in front of it!
If I changed the thermostat, maybe moved the reserv or put in some thermo guard, and maybe installed a oil or trans fluid radiator cooler do you think that would help? Has anybody had any luck with these things?
W/so much talk and youtube vids out there why am I the only one on this forum that has this problem?
Do I stink?

OnAll4s

Ok guys. Here is the deal... advance auto computers and any of the 6+ ECM/PCM resellers out of orlando florida ALL have F ratings with the BBB.

You have a 1in 4 chance to get a good board from them and if you don't, be prepared to fight to get them to honor their warranty.

There a few ways to test the PCM. Withstand the engine running torque/ press on the PCM and wiggle connectors slowly... if it is a connection issue it will die out. Same with pressing on different parts of the PCM itself.

I replaced my connectors with ones I cut from the junkyard. Then went with the dealer PCM. Been over a year and not one problem with it..?

Lufthq

Thanks "onall4s" for the timely reply....... too bad I went in and ordered a rebuilt PCM yesterday from Advanced! This one is from A1 Carbone I think, they seem to be in the Philly area of Penn. I had heard about the "F" rateing from the company in Orlando Fla. and made sure not to order from them, so where does the dealerships get their PCM's from? I am sure they do not do it themselves.
I tried the test of vehicle running and you pull tug on the PCM unit and wires, No stall or shut-off. From the one time it did it to me and the short history I got it seems to be a heat issue, but not an over heating issue.
That is why I was asking if anyone else has found any relief by replacing the therm-a-stat, oil coolers/radiators, etc.....
It's funny how the tech's and even the guys at the dealership have no idea what is wrong w/these jeeps, they just go down the list of things to replace and after a couple of grand is spent lets try the PCM! I was hoping to get some real help/suggestions here but it seems no one here knows any more........ or is just not willing to talk about it.

Owning a Jeep is getting more and more like joining a religious cult!

OnAll4s

Best of luck man.

The dealership obtain them from the same sources. However tthe companies they used remanufacture them. A rebuilt replaces only parts that are out of tolerance. Reman'd replaces all key components(transistors, ICs, relays,etc)..

Now temperature can create problems as the solder used on circuit boards has a lower melting point than most metals. So as you can imagine if your engine is at 190-200 you can best bet there are some areas of the engine bay that can exceed that by quite a bit. Most PCM issues are the same as the VIC problems on ZJs. Bad solder joints.