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Jeep Grand Cherokee PCM Module Replacement

dburdendburden Posts: 1
I have a 2001 Jeep Grand Cherokee and the dealership told me I need a new PCM Module (Power train Control Module) at a cost of ~$850 plus tax and labor. I found the part on the internet for $336 but is this something I can replace myself? The service manager said this is basically a computer module. If I can replace a power supply on a PC it seems I could replace a PCM. Any advice? Thanks.


  • I'm sorry but I can't help with your question, however, I was wondering what problem you were experiencing that you need to replace the PCM? When I am at wide open throttle in my 1999 JGC my guages go wacky and the headlights/instrument lights get very bright. I am told it could be a PCM problem but know nothing about it. This isn't the same problem you are having by any chance is it?

  • tuggajbtuggajb Posts: 646
    not to hard
    located on pas side under hood on the fire wall behind coolent tank don't look to hard to change
  • Hi, I've basically got the same problem. I've been told by the Jeep dealership that I need to replace the Powertrain Control Module (PCM) which is going to cost me $900. I asked if there was a cheaper alternative and he said it's an internal short and there is really no alternative and that I can only buy this part through the dealer. This all started with my car being unable to start. It tries to start but will not turn over. He says the PCM tells the car its ok to turn over. Anyway, does anyone have any advice for me? $900 is a pretty heavy hit on me right now.

    I really appreciate any advice on this. Please click on my username and respond to my email. Thanks!
  • tidestertidester Posts: 10,059
    Please click on my username and respond to my email.

    If we all went to email that would defeat the purpose of a Forum and deprive everyone else of valuable information! :)

    tidester, host
    SUVs and Smart Shopper
  • Oops! He's right. Please advise on forum.
  • tuggajbtuggajb Posts: 646
    sounds as if starter relay
    located on the pass side under hood in the fuse block under the cover cover should show which relay it is
  • I also was told my PCM was out so I bought a used one and it still didn't fix the no start problem. I have spark to the top of the distributor but not to the plugs. I thought it was the cap and rotor so I replaced them too and to no avail it still wont start? I did use and aftermarket cap/rotor so I got a OEM set. Any ideas? I took it to the dealer and they said the cam/crankshaft sensors were working. I was just going to throw money at it until it starts. I love my Jeep and wont let it die on me.

    Please help me?
  • tuggajbtuggajb Posts: 646
    if you have spark to top of distributor cap but none out remove cap have some one turn engine over and look see if roter is in fact turning
  • key has to be left on for a while till some thing clicks then it starts
  • I did check to make sure that the rotor was turning and the distrbutor was moving correctly. I am just getting frustrated at all the dead ends? The dealer said it was a PCM and I replaced it but it still did the same thing? They put on the paperwork that they checked the coil,CPS, and the camshaft position sensor and said it was fine. another option I was thinking about was to have my PCM tested or rebuilt.? I guess from what I have resurched so for that Borg Warner re builds them? This way if there is nothing wrong with the pcm I could take it back to the dealership and get my money back for there wrong diagnoses?

    Any help here is great!
    thanks in advance!
  • lunghdlunghd Posts: 61
    Sounds like the cam shaft position sensor - located below rotor. Easy to replace on newer engines & NAPA / AutoZone etc part...
  • The dealer said and also posted on the bill that the camshaft sensor was good.? Should I replace it just out of elimanating that fron the equation?
  • Any Ideas on what to do next? I would like to get my Jeep back on the road! Any help here would be great! Thanks
  • tuggajbtuggajb Posts: 646
    if you get spark to the dis you should get spark out no matter what position cam is in so if you remove spark plug and ground the center electrod to the engine it should spark when some one turns the engine over if it does then you can check that firing order is right
    to check remove number 1ne spark plug put your finger on the spark plug hole and have some one turn over engine when you start to feel pressure on your finger stop turning over engine and then move it with fan belt to get to top dead center
    remove dis cap and see if roter is pointing to where number 1ne plug wire is if so
    try this stuff and get back to me
  • I checked for spark after the distributor cap and firing order but it still won't fire off. Could a weak coil cause a poor spark, subsequently not getting enough spark to the plugs???
  • tuggajbtuggajb Posts: 646
    could be
    were you getting any spark at plug (should be a good blue white color)
  • Again, I am not getting any spark to the plugs. I pulled the wire off and put a new spark plug in the end of the wire and saw no spark. If the spark was low/poor from the coil woild it still have spark at the end of the spark plug wire? I checked to make sure the firing order was right and it is. This is what happend to start off with, I was pulling my boat out of the water and stoped at the top of the boat ramp and turned off the engine. It NEVER restarted and this is where we sit now. I am sure is somthing realy stupid because it was running just fine before I turned it off. Thanks so much for all the help.
  • tuggajbtuggajb Posts: 646
    try and just hook the coil wire to your new spark plug and see if you get a good spark should realey spark when you turn the enginne over
  • I did that and the spark looks ok? I am just at a loss on why there would be spark at the coil and to the end of the coil wire into the cap but not out into the plugs? Am I going tin the wrong direction here?
  • tuggajbtuggajb Posts: 646
    try to put the old roter back on sounds as if you have a bad roter even thogh it is new just replace the old stuff back on and see if you get spark has to be short inside dis cap or roter
  • Did that too, still the same problem. Besides It just quit on the boat ramp and wouldnt start so I replaced the cap and rotor 2 times now one with the jeep oem and one with the schucks aftermarket. them I put the one that was on the car back on and still the same thing...3 bad rotors?
  • Hi
    I am reluctant to take my jeep into the dealer but have had no other choice. The jeep has a new battery for starters and cranks over, just does not start. The fuel gauge is not reading with the key in the on position. The dealer says they need 2-3 hours just to figure out what might be wrong. They are indicating maybe the PCM, TCM or the cluster.. they don't know. Currently he indicates he can't communicate with them. I have looked through a lot of information and it appears maybe the PCM is the problem. Two Questions
    Given the symptons does any one have any advice?
    Does any one know where to get a PCM other than the dealership that is legitimate and a decent price.
    Any help would be great thanks.
  • Hi

    The pcm is gone on this 2000 GTC 4.0l and the dealer indicates a skim module is also required (sentry module key). Is this true or can you just replace the PCM after it has been programmed for the vehicle? No one seems to want to give this information out they just want the 1000.00 for the pieces. Any help is appreciated.

  • lunghdlunghd Posts: 61
    Sentry module? OEM alarm system? Ask the dealer to fix THAT first & be sure to mention you have a 'SPARE' PCM ready & waiting so no need to put a new one in just yet... *(Unless it's a freebie under warranty!).

    The danged OEM (and aftermarket...) alarm systems have been known to go out & prevent starting.

    There's also the ever popular ignition switch (not the key unit - the electrical switch itself), there's an interlock / latch relay, the fuel pump (has ya got's pressure???), the Neutral safety switch (NSS)...

    Hmmm - NSS... Have you tried starting it while cycling thru the gears w/ your foot on the brake??? Just turn the key to start w/ one hand & use the other hand to go from Park to 1-2 & back up. (Keep yer foot on the brake!) The NSS, which is down below where the water from that boat launch was, could be full of water & gummed up. Fairly easy to remove & rebuild. (Article & 'how to' linkages on my website.) Crown Automotive online sells them for about $110, Don't even ask what the dealer charges...
  • Humm, Interesting thought. I never thought of a NSS before.Dosent the NSS keep the starter from working? It will crank over when use the key but I will try to see if it does when I run it in the gears? So if it continues to start while in gear should I replace the NSS at that point? What if the same thing continues? Is the factory alarm system integrated in the PCM? Because when I got another PCM from the bone yard they asked if it was a factory alarm..? all I know is it has the key card by my knees and when I pull it out it disables the starter. The horn doent beep or anything like that.

    Where is your website link? just in case I find the NSS to be the problem
  • I am seeing the same problem mine has no communication to my scanner also I have no gas gauge or volt meter woking with key on. I have had my pcm reconditioned and that did not make any difference. Mine died just driving down the road will post any more findings.
  • Listen i let the dealer look at got the story that they need 2-3 hours and it turned out to be the PCM. I have ordered one (New one) from a company in the states that takes your serial number, color of ignition key and programs it. I will be getting it this week and can let you know. I parked my jeep one night turned it off, next morning would not start. The symptons you are telling me are the exact same ones I had with the exception it did not die on the road. The dealer also said the scan tool would not communicate with the cluster, pcm, tpm .. thats why they wanted 2-3 hours.
  • dulyddulyd Posts: 2
    the voltage regulator is bad and it is located inside the pcm hurry and replace it before it quits. has them for cheap. :shades:
  • Well after checking over everything my crank position sensor was internally shorted causing a back feed the pcm causing a loss of communication to the scanner. I replaced sensor all is well.
  • Hi

    I tell you I did the exact same thing after the PCM did not correct the issue (as directed by my dealership which cost me 300.00 bucks to diagnose) and the sensor fixed everything. For all those folks out there that have a similiar problem, change the sensor first - its cheaper and likely the cause.
  • I had the same problems with my '97 Grand Cherokee, I did have the PCM replaced, I bought it from the dealer thinking that any mechanic could install it, I was wrong, only the dealer had the computer that programs it to your car. It helped somewhat, but still it starts sluggishly.
  • When you buy a new computer you just have to supply the serial number to your jeep and they can program. I live in Canada and ordered one from Florida for 280.00
    The crank position sensor solved all the problems and I didn't need a computer, the dealer was wrong. is where you can get reasonably priced parts.
  • I have a 1997 jeep grand cherokee with a 6 cyl engine. the check enging light came on and when the code was checked it said "Direct battery input to PCM was disconnected within the last 50 key-on cycle. Does anyone know what this means. The engine still runs good. I unhooked the battery hoping that the light would go away. It's still on. Could a sensor be causing this?
  • rickeylee...pretty sure that's your pcm/ecu....the main computer. My '94 did the exact same things you described. You can buy a new or used unit or do what I did: I changed the 3 capacitors on the ecu and haven't had a problem in the 2 years since.
  • How the heck do you get to the crank position sensor on a 93 V-8 Grand Cherokee. Looked under and above and can not see it.
  • It located on the transmission close to where the tranny bolts on to the engine. If your looking at the front of the truck, it would be at the 1:00 oclock position.
  • tuggajbtuggajb Posts: 646
    have you disconected the battery for about 10 min to reset the computer to fac defaults? then hook back up and drive for a bit to store new parameters to sencers
  • weewee Posts: 3

    i have 2001 jeep gran cheer and was having problems starting i did key trick and got code for crankshaft position sensor replaced and truck started.

    after replacing and starting,truck started running ruff and stalling.did key again and got codes p0351,p0352,p0353.ignition coil.

    changed ignition coil pack and code p0351 went away and p0352,p0353 are still there truck is idling ruff and still stalling code says dwell time not sure what to do if anyone with same problem or anyone who knows what to do please help trying to avoid dealer and costly unnessary inflated pricing for repair work.

    please help!!!!
  • Well I thought I would give an update to what I have learned so far. I had my PCM rebuilt/checked and after spending 200.00 it came back saying that the PCM was in great working shape. So then I decided to go ahead an replace the Cps(crankshaft Position sensor)thinking that might be the problem as well. Nope still wont start. I am so frustrated at this point I dont know what else to do? Should I spend the money and try the coil next? I cant belive that it wont start yet. ANY IDEAS would be great! Thankyou so much for any help that you could provide.
  • tuggajbtuggajb Posts: 646
    are you getting spark to plugs?
    if not see if getting spark out of coil (can test coil by omes meter )
    do you have batt voltage to the neg side of coil (need to check when turnning engine over votl will go on and off as dis turns )
  • rev4revrev4rev Posts: 11
    Replaced CPS and installed refurbished computer now has code 12 still and 37 which is torque converter switch. Would think it would start even though it has 37 but it will not. Has spark and fuel pump sounds to be running. Any one have any other ideas?
  • rev4revrev4rev Posts: 11
    Did you ver get this worked out?
    I have replaced all kinds of parts and have spark at coil but not at spark plugs.
  • rev4revrev4rev Posts: 11
    How did you get the jelly stuff off of the board to replace the capacitors?
  • rev4revrev4rev Posts: 11
    I have no spark at spark plugs but when I remove coil wire at dist. cap and put a plug in it it has great spark. Even opened up gap to 1/4" on test plug and it still sparks from coil. Have replaced crank sensor, PCM, Plugs, Wires, Cap & Rotor to no avail. Timing looks to be on anyone have an idea what to do next? Is it possible the rebuilt PCM is firing coil when rotor is inbetween contacts in cap?
  • tuggajbtuggajb Posts: 646
    do you know how to check if you dis roter is pointing to number one plug when on top dead center?
    (pull number one plug turn engine over with your finger covering plug hole when you feel pressure stop turning engine with starter and then move crank with socket till timing marks lign up look at roter and see if pointing to number one plug wire (bet it aint) could have two things wrong 1 timing chain worn out jumpted time there 2 dis drive gear pin seared
    hope this helps
  • rev4revrev4rev Posts: 11
    I have same problem did you ever figure out what is wrong with yours?
    I have replaced pcm, crank position sensor, cap rotor and wire to no avail.
    Coil wire will spark across 1/4" gaps easily.
    Cam position sensor shows good.
    Wonder if rebuilt PCM is bad?
  • I have spark at the coil, its weak but I do have spark. I have no spark at all to the plugs. Now before we jump the gun here,Yes I put a OEM cap and rotor in thinking that was the problem but to no avail. I changed the PCM, Crankshaft sensor,cap and the rotor.Nothing? I was going to put a new coil in and see what happens. Any other advice?

  • rev4revrev4rev Posts: 11
    Did all the same finally the second new coil fixed the problem. I finally took the coil off of a running jeep and put it on and it ran fine. So I guess just because it is new does not mean it works. If you can find a wrecked jeep that runs you can switch out parts with it till it runs. I figured that one out after hundreds of dollars. Funny how we learn lessons the best when the cost us big bucks.
  • Thankyou to all of you who helped out on this seemingly endless aray of problems that I had with my JEEP. Turns out after all the B.S. from the drealer that they were way off base. It ended up being the 40.00 coil that just would not diliver enough spark to the distributor. Wow,what a releif it is to have my JEEP back on the road!
    Any ideas on a recource that I could take to the dealer about getting my 600.00 back from a poor job that they did?

    Thanks again
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