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Jeep Grand Cherokee PCM Module Replacement



  • kjarrikjarri Posts: 1
    Hi. vhen i swits on it not start but if im whaitin for som sekond the chec engin kom on an the auto shut down raily klikk an then the ligt go of an i can start and its ok,
    pleas post som ideas.

    rigard. Kjarri
  • tuggajbtuggajb Posts: 646
    i would replace the ignition switch first as that is a lot cheaper than a pcm
  • mrspeed3mrspeed3 Posts: 1
    edited August 2010
    I was jump starting my JGC Laredo at night when the postive cable hit the negative post momentarily causing a significant spark. I then tried to start it but got the check engine and sentry lights that never extingushed. Gauges on instrument cluster also went wacky. I checked all fuses and they are fine. From what Ive read it sounds like the PCM may have been damaged. I took it out and want to order a used one off of ebay however is this the only potential solution? Will a Jeep dealership have to reprogram the 'new' PCM? Thanks
  • you can buy recond PCMs from several dealers on ebay. Furnish VIN,current
    miles,and old PCM model number. They range from 165.00 to 250.00 and have
    lifetime warrenty. They are plug and play,no trips to dealer etc and have phone
    numbers if you need guidence
  • Engine turned over great. Gas gauge lite on but knew had 1/4 +. SKIM lite on,ck gauges on,ck engine on. COULD NOT LINK TO PCM. Repair shop said PCM bad.
    They wanted 1000.00 to replace. Furnished VIN,miles & PCM Mdl num to ebay dealer. Got it overnite,free shipping. Installed with same results. Saw msg here about Crankcase Position Sensor so I found the connector(located on right side of
    engine near pan-block join by xmission ck tube) and disconnected conn. Gas lite out and showed correct gas,SKIM lite out,gauge and ck eng on but should be. Could now link to PCM.
    New CPS @ AutoZone $46.00. Installed(A MAJOR PAIN because of space)-disc shift link & bracket first and small hands help. Started and runs fine(leave run for 10 plus minute so PCM reads all inputs)
    Repair shop no can find in fac bull. All is well.Thanks to advice from forum
  • Cthessing: Please tell me if you fixed this problem as I am having the EXACT problem. It is dangerous driving with no brake lights/signal lights. And it is intermittent, dealer could not recreate the fault. We are gonna switch the ignition switch first, and then the very expensive PCM.
  • Cthessing & napagirl, I had similar issues in my 2005 Jeep Grand Cherokee, Limited, 5.7L. The inside panel lights would flicker on and off, A/C would work intermitently, wipers would come on and off on their own without rain, sometimes car wouldn't start, I would have to remove the key, re-insert and try again, it would shift roughly in and out of MDS, etc...basically the truck acted like it was possessed by Gremlins. My husband unplugged the negative battery cable for 20 minutes to allow the ECM to re-set and the car has been driving like new ever since. All of the electrical issues have disappeared. It might not be the cure for your vehicle too, but is an easy fix to try out.
  • Thanks for the reply, Jeepers 19. We did just that to get the car to reset (disconn battery), but the problem would start up again intermittently. Was advised by a Jeep Mechanic online to replace the ignition switch (which we did ourselves- $45 vs $200 @ dealer). It has been about 10 days since we swapped it, and I have had no problems so far. I am assuming that was the fix (hopefully). According to the mechanic online, this is a common problem with the jeeps, and the swtich sends out low voltages to the accessories, and if there is a short, then the accessories can stop working. This is what would happen to us... things would stop working until we reset by disconnecting the battery. Then it would eventually do it again. We never experienced things coming on crazily like some others on this board did.

    If ignition switch wasn't the problem, the online mechanic recommended flashing and/or replacing the PCM next.
  • I hope the ignition switch was the cure for your Jeep. Let me know if it does the trick and I'll replace mine. I know my battery disconnect was probably just a fly by night kinda fix. My JGC still seems to be running perfectly smooth after a month, but we'll see how long it lasts. After reading about all of the electrical issues people in this forum are having with their JGCs, I am tempted to just trade mine in. I would hate to do it because I really love the vehicle, but I'm afraid to take any chances with it on a road trip. You just never know when the electrical issues might resurface.
  • It has been over 3wks and all is well :-) Ignition switch seems to have cured my problem, but my things happened when turning jeep ON. see my original post which was very specific.

    If not your problem, try having the PCM (power train control module) reflashed or replaced (expensive).

    That's my only advice re: online mechanic I paid and consulted. He indicated for my specific problem to do ignition switch first, and it seems to have worked.

    It was a $45 part, and my husband replaced it in an hour. dealer wanted ~200.
  • So I purchased a 2005 JGC Laredo about 3 months ago with 49k miles. Since then (now 52k), i have had the passenger-side power outlet replaced (blown fuse) and more recently, the CD player has ceased to work. (the radio still works). The dealership has determined that the CD module has had a "system failure" and that was the only code to appear throughout the Jeep. Also when driving, all the dashboard lights will turn on and off (about 3 times). In the meantime, the speedo and rev meter are going from the normal to 0 and back and forth. But the performance doesnt change. The dealership cant reproduce the e same problem ehter. Also the my JGC starts up on the 2-3rd start and not the first anymore. Does anyone know what is going on with my JGC!?!
  • I have a 2005 Jeep Cherokee. Have same problem as many postings -- Dashboards icons flicker and outside lights flicker intermittently since Nov '08. I've recently replace the PCM but after the Instrument Cluster twice, a battery and an alternator. I'm STILL having problems AND the flashing as escalated at night with the dashboard and lights staying in the off mode Longer. I'm SCARED now and this is final attempt to get any suggestions for what to do next !!
    Please Help !!
  • So, I've been there before. Good news though, since my last post I have had the problem fixed with the dashboard lights (knock on wood). I did a little research on my own and decided to have the dealership check for a code that doesnt appear on the computer unless they search for it. I had them search the code for the "ignition switch". The code came up and they said that it needed to be replaced. After they replaced the ignition switch, my Jeep has been running great. Hope this helps, its not too expensive but worth a try. Good luck.
  • Ok guys I'm a 50 years old mechanic. 30 years in my SON bought a 1997 Jeep Grand Cherokee laredo omg any way running like it had a demon in it.
    we first changed the fuel pump that was bad then looked like it had 4 lbs of mud in it. Cleaned the injectors checked for codes still same problem. Recently the distributer had been r&r new. code 320 replaced the Crank sensor. it started and ran better. But ruff idle, Then a noise started in the distributer but all of a sudden it was running better HUH? Changing the distrib in a few min. Maybe I should leave the noise alone. Auto Zone distrib hint hint... By a Chevy next time!
  • Just got done replaceing the head gaskets on my 2000 JGC 4.7. everything went fine. after all was done my ac compressor is not coming on. check all conectors. disconnect the ac switch and jump it compressor came on. replaced the ac compressor switch. still not working. did not disconect any of the ac system when doing the heads. plus check all fuses in the engine comparment. good. is there something else that i am missing, besides replacing the computer, because i think that would be the next thing. any help would be cool thank you
  • talkjeeptalkjeep Posts: 1
    One month ago, my 2005 Jeep Grand Cherokee would not turnover to start. Had it towed to local jeep dealership. Diagnosed as a bad Power Train Control Module, to be replaced under warranty. Part has been on backorder for one month without any restocking date from "their vendor." Told by their Parts Dept that there are 43 other customers nationwide awaiting this after market part. They have no idea when it will be restocked. Fought for 2 weeks to get them to pay for a loaner/rental car. They OK'd and are paying for a stripped down Dodge Nitro that is a back killer to drive. Every week I call - they say there is NO RESTOCK DATE. I offered to let them keep my jeep as a trade in at Kelly Blue Book trade in value, plus the cash difference that I could afford to buy a new 2011 JGC with the comparable upgrades. They wouldn't accept my offer (a few thousand shy of their bottom line). My two questions:

    1. What are my rights (their obligations) since they are not honoring their warranty; they can't tell me when, if ever, they will be able to get the PCM Module to replace it; and I can't use the car in its inoperable condition as a trade-in on any other makes if I choose not to buy another jeep???? Note: the Jeep District Manager refuses to meet with me to discuss the situation.
    2. At this point, if they can't get the part, and since no one at Chrysler corporate will help, how can I get them to buy me out at the Kelly Blue Book trade in value so I can shop for another vehicle make?
  • jgcguy77jgcguy77 Posts: 1
    talkjeep....I hear you...I am so frustrated with my Jeep GC 94. I am on my 4th PCM. I love my Jeep and have from the minute i saw and bought it used 10 yrs ago....I cant begin to explain how angry I have been when ever the PCM has failed. Im not positive but it seems alot of the issues have been caused by an electrical short somewhere. In my case it apparently was the wiring harness in the drivers front door and it doesnt take much of a short to cause the PCMs to get fried. I too would like to be rid of the problems, but finances wont allow so I have to gamble on yet another PCM. I wish there was some legal way to have Chrysler go good for all this mayhem....As you know by the apparent runaround that you have been through, the dealers(or most of them) are terrible at looking after honest customers. I wonder how many of us there are.??!! to all of us going or gone through this...good luck!!
  • My 2003 JGC power windows and locks will not work only when it is below freezing. After the vehicle warms up they work fine. When you work the switch there is not even any sound from a motor. Nothing. Anybody have this problem or know what to check or how to fix it?
  • iamjeepiamjeep Posts: 1
    edited April 2011
    2011 Jeep Overland purchased end of March and in less than 3 weeks air suspension went up. the suv height set way up. Has this happen to anyone did it reoccur after they replaced
    computer chip
  • rgarmonrgarmon Posts: 9
    Hi Jeff,

    Hopefully you are still on this site. I have major problems with my 2001 JEEP Grand Cherokee. It first started a few months ago while driving, the JEEP would jolt as though it was trying to cut off. After a month of that it did start cutting off while driving and at stop signs/lights. I would have to put the car into neutral and restart- while driving!!! After about 2 months of this it would not start easily, or it would start and cut off within 10 seconds. After this it totally died and I had to replace the battery. So, after I replaced the battery the JEEP started, but still with the same problems listed above. Additionally, there are other things going on that I believe are related: the speedometer fluctuates up and down, the digital gas reading fluctuates- it will say 100 miles to empty then 0 miles to empty then 24 miles to empty and so on. Not sure if these are all related. Additionally, I had the altinator tested and it was 13.5 (kind of low).

    The dealership ran diagnostics, but couldn't get a reading because they said "it would fix itself and no codes would come up."

    Now they are telling me to replace the PCM. They want $900 total! I have already put so much into this JEEP to no avail. After reading some of these posts I am wondering if it may just be a coil? Please help. I need to know what questions to ask these jokers- like did they test for spark??? Please give me some ideas and maybe a list of questions to ask the dealer to see what they did to determine that it is the PCM.

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