Jeep Grand Cherokee PCM

tbull15tbull15 Member Posts: 1
I went out and started my Jeep up without problem. I then drove it about 30 miles and shut if off for about 3 hrs. Again, I went out and started it up without problem but the Abs, check engine and airbag lights were on. When i tried to drive it, I couldn't get over 20 mph with it floored and the gauges began to flicker. Pulled over, turned it off, started up and the same thing happened. Left it for the night, started it up again and it spit and sputtered terrible while the guages flashed on and off. It finally deseled out and stalled with a puff of smoke through the air-breather. Checked fuel pressure and fuel pump, both are fine. There are also no error codes. It is at the dealer now and they have ruled out mechanical failure; so now it must be electrical right? Could it be a sensor? or the PCM? Any ideas or help would be appreciated.


  • everlastboi69everlastboi69 Member Posts: 1
    Hi I was having the same problem with my 200 jeep grand cheerokee laredo. :sick: I keep taking to the dealer they couldnt figure out what it was. Lucky for me my father is a mechanic 2 hours from my house so one day the jeep was acting normal i drove to my dad he put the computer on the jeep and discover it was the Speed Out Put Sensor :surprise: ... Guess what dot be fooled. this peice only cost me $16.00 us to fix granted the labor from my dad was free. have them check to see if that is the problem.Ever since mine was fixed it has been running, great :shades: ((KNOCK on WOOD)) Also Chysler Makes Jeep. :surprise: If this happens to you pull the jeep safely off the road. Turn it off, and you must remove the key from the ignitian for 20 minutes. some models may take 25. the jeeps system will reset. so if signs of electrical or sensor problem this can temporarly fix. I realize trust me it dosent help when your in a hurry or on the exspress way. but it works if problem keeps continuing you need to fix it qiuck. :)
  • erwin2erwin2 Member Posts: 2
    Vehicle has been in for service three times for high idle problem when warm. the problem has started again. has anyonelse had the same problem :cry:
  • cherokeedave2cherokeedave2 Member Posts: 1
    I just remembered how to check fault codes by turning key 3 times. It spit out code 0320 Crankshaft position sensor (CPS) I think I’m on the right track as this produces the pulse train to the PCM and injectors, purchased a new CPS from autozone for 60.00 along with replacement info. I was able to disconnect the connector from the left side of the eng. above the starter ohmed out pins B and C, should read infinite resistance mine read close to 0 ohms. HOWEVER, even though I have long arms I have big hands and can’t seem to find the nut let alone remove. If anyone has a method I would sure like to know, such as tools used, pics etc..or I’ll have to take it to a Dealer..OUCH Thanks
  • lawrence56lawrence56 Member Posts: 2
    I have a weird electric problem no one can figure it out. Sometimes I try to open the door with the keyless button nothing happens. I open the door with key the dome lights don't go on, I try to start it the gauges spin around and won't start after two or three times it will finally start. I also found out if I open and close the driver door a few times the dome light goes on then it will start. I took it in and had the ignition switch and the pcm computer replaced. The Jeep is perfect other than this problem.
    Does anybody have an answer?
  • heydenoheydeno Member Posts: 6
    I have a 1996 Jeep Grand Cherokee 4wd I have been dealing with problems for about a month. It first started dyeing when i would sit at a light but it would start back up and was able to take off. Then it would on occasion not want to start it would crank and crank but not start if you shut the key off and waited then it would start. It seemed to happen more when the engine was cold. It has been scanned about 5 times always the PO351 code would come up. We thought it was the coil so we replaced it with a aftermarket coil a higher performance since there had been so many complaints about the plug problems on the old coils. It did nothing. When a fuel guage was put on my jeep it was jumping all over the place so they told me I needed a new one. Replaced that big $ still had the same problems. The distributor and pick up have been changed along with the crankshaft sensor I am thinking the only thing left is the pcm but that again is big $ and i am really frustrated at this point. Do the PCM's have to be programmed when you purchase them and does anyone have any different ideas? I cleaned all electrical plugs on the pcm and other items or could the crankshaft sensor still be bad even though it is a new one?
  • juan15juan15 Member Posts: 1
    they sell pre-programed pcm's for jeeps on ebay for between 150.00 and 200.00 hope this helps because i just paid Chrysler $1200.00( i wish i knew about the ones on Ebay) for the replacement of my pcm and its only been a month and i'm back to the same stalling and i get the key symbol. I 'll be taking my jeep back this week and hopefully they can get to the bottom of this. ;)
  • heydenoheydeno Member Posts: 6
    thanks for your comment since i posted my comment i replaced the pcm and yes I still have the problem. It still looses spark at times. Everything has been replaced. So if you get anything new please let me know. I have thrown alot of money away and nothing has fixed it.
  • 96jeep296jeep2 Member Posts: 11
    Looks like alot of us are having the same issue, anything from not starting all the way up to stalling while towing a boat 15 mins down the high way. This is absolutely absurd!!! I have changed everything in my car and I still can't get it started, maybee the goverment should have let Chrysler fall right on it's face, just like chrysler is letting their customers do. I dont think it's any of the sensor's, pumps, hose, fuse or switches ; I think it is the whole wiring harnes it self! It has to be, we replace every sensor, switch, hose, fuse, and the pcm! If we replaced everything its got to be what connects of of them together. Jeep is known for, not have a great electrical system to begin with. I dont know I am not a mechanic, but I do have a brain. Oh were was that brain of mine when I started this crap!! LOL any ways. I spent way to much money on this, At this point is would be foolish to give up. Any one know were I can get a new wiring harnes, that hopefully dose not coast an arm and a leg, i only have a few fingers left.
  • heydenoheydeno Member Posts: 6
    I am at the same point as you. I was told it could be a intermittent injector problem. One that is shorting out which in turns operates the coil. I haven't done anything with it yet I have replaced everything on my jeep as well. It has cost a ton of money and nothing has fixed the problem. If you find out it is the wiring harnes will you let me know? I have no idea where to get one except from the dealer which will cost alot. If you get a used one you could get the same problem...
  • reonereone Member Posts: 1
    have a 2003 grand cherokee 4.ol 82000 miles tem gauge goes back and forth from 100 to 260 replaced thermosat.coolant sensor /ground wires were clean /instrument cluster was change nothing seems to work for long when grounds were cleaned worked perfect for 3 days now seem thing.had it to garge when it was acting up although tem gauge was near 260 engine read 208 so it's not overheating.any ideas would be very helpful. garge now tell's me i need ECM computer
  • heydenoheydeno Member Posts: 6
    That does sound like you have a shorted wire sonewhere. Finding it will be the problem. Mine will run good for days and then will mess up out of the blue. You never know when it is going to happen. Someday hopefully we will find the problem
  • tuggajbtuggajb Member Posts: 646
    next time gage acts up just wiggle the key a little dont sutoff but just wiggle it a little see if takes care of prob if it dose then i would replace the ignition switch
  • 96jeep296jeep2 Member Posts: 11
    Yea I went to the dealership looking for a harness and it's basically a billion dollars, but I did find out that their are a few recall's one being with a certain pcm witch I happen to have so i dropped off my car and they are working on it i should hear back in a few days, oh by the way the pcm # is 56043172, the recall is for a erratic idle and intermitan loss of some light's gauges etc.... the pcm needs to be reconfiged not replaced, if you replace it you will still have the same problem, so they say..... till next time, hopes this helps and will let you now how i make out.
  • 96jeep296jeep2 Member Posts: 11
    he i was able to replace mine, took about 30 mins but i got it done, but you prolaby been replaced already. post back you needs help
  • dixiecsadixiecsa Member Posts: 1
    I have a 2000 Grand Cherokee Lorado, 4x4 4.7 L My Jeep has been giving me a Code Falt (Engine Light) # P0300 Random Missfire Didplug's. N.G. I Changed all the coil packs. N.G. I cleaned every plug in connecter under the hood with contact cleaner. N.G. I did a fuel rail test lbs. where good. All inj. where good. N.G. I Checked for vaccum, No leak's. Still N.G. Changed Temp. sensor. N.G. Jeep said there was a service bulliten came out, 1 down-load for driveability issuses, And 1 down-load for Tranny. Had them done. N.G. Then changed Cam Sensor & Crank Sensor. N.G. Don't forget every-Time I do one of these repair's, I clear the codes-engine light. And every time that DAMN P0300 Code Kept coming back.Any where between 2-3 days to a Month. Also since this problem My GAS MILEAGE HAS GONE TO ++++ in a hand basket. Know since I did the Cam & Crank Sensor there have been no codes for 1 Month. WAIT till Today A New Code... #P0601 (Check Sam Error) Witch means PCM Jeep want's $700.00 Reman can't get New. So I call around, Turns out NAPA has them 1 Yr. warranty. $121.90. Now it has to be Reflashed. I take it to Jeep they fash it, you know put some brains in it. Install it they road test it, All is well. Another $176.00 for Reflash. I Leave the Dealer Ship drive down the road to the Sunoco Station. Fill Her Up. Get in Start it up. I jot down the mileage so I can check th MPG out. And The Jeep Stalls !!!! I Turn it Over Nothing. No Spark you can here it, Just spining over like a TOP. Im madder then a Hound Dog with Flees. So here I am 40 miles from home 5:15 PM Jeep is Closed. I have no tool's. A Leather Man on my belt. I pop the hood, Take out the 2 10mm scews holding the rad. over flow tank. Pull it out unplug the 3 connecters on the PCM,Take my old PCM out of the box on the front seat. I fit down by the connecters and plug it in, It fires right up. The remann pcm is N.G. Mow I call Napa before they close at 6:00 They said sorry I'll order another. Have it in 2 days. I say wait a minuite, What about the $176.00 I just paid for the Reflash. They said they'll take to the company about it. So I pick a pizza some Coors Light.& go home. With the Idiot Light On Still. 1 YEAR LATER> Today is Wens. 26th let ya"ll know how I make out. I am hoping to change out the PCM & be DOWN. Or am I DREAMING. If I didn't lov this Dam jeep so much, I bought it 3 years ago fro the org. owner with 76,000 miles like mint new. The man littery only sat in the driverside, No Pass. No people, Never used the rear seat or cargo area. For 2 years it was great, But Chasing this problem is driving me nuts.
  • mercyme6mercyme6 Member Posts: 10
    I am having same problems with my jeep,the check engine light does not come on when trying to start wants to start then doesnt no spark to coil or pcm took out tested coil it was bad, tested again after removing it tested good.,fuel pump is good but still no spark, ordered a pcm off ebay for $80 that came out of 93 grand cherokee same as mine but then talked to a mechanic and they said i hope it works or hope you got the right one because he said that there are different numbers and if they dont match it may not work is this right?i guess i just thought if it came out of the same year vehicle it would work.any suggestions on fuel, pump is not starting but fuel gage is good fuel pump was replaced no spark to
  • heydenoheydeno Member Posts: 6
    They are right replacing the pcm it has to be set for the vehicle. When I ordered mine I still had to have it set they call it " Flash". On mine I think we found the problem. It was a shorted out fuel injector. When it shorted it would cause it to have no spark to the coil as well as have alot of other things go haywire. We replaced the fuel injector and it has not gave me any problems since. It has been about a month. So hopefull we did get the problem fixed. I am still keeping my fingers crossed though because it has been such a problem and costly.
  • omniss69omniss69 Member Posts: 1
    I nought a 94 jeep GC with a 5.2 and it wont start. its got power to the coil but no spark to the plugs it wont energize the fuel pump . the check engine light doesnt come on when you turn onthe key nor does the security system . and the display in the radio console area where the over head of the jeep is doesnt show doors ajar or anyother things does crank over though
    any ideas would be appreciated
  • morley46morley46 Member Posts: 2
    Trying to do the exact same thing on mine, found the nut okay but you are right about the lack of room, looks like it needs an extended socket wrench handle to get at it from underneath. A further problem i have with mine is that a cable runs right over the top of it!
    As an aside to that problem i have had most of the problems posted about lack/loss of power and still trying to fix it, replacing the crankshaft sensor is my next option.
  • tuggajbtuggajb Member Posts: 646
    bout 2 or 3 long extensions to get at the crank censer when you tighten it dont over tighten as will crack it bout 10 15 inch pounds (not much) just so will not fall off not holding the jeep together with that bolt
  • melbistylzmelbistylz Member Posts: 5
    The problem is that the PCM is grounded by the firewall. I'm sure you've fixed this is an old post but if anyone else reads this. The PCM is grounded by the firewall. I found continuity with an ohm reader. I say manufacture defect. if anyone still wants to know how to remedy this stalling, electrical problem, I will be glad to share my research and answer. Original owner of a 1996 Jeep Grand Cherokee Limited. Still running after all that.... Saved a lot of $$$ working on it myself.
  • steverstever Guest Posts: 52,454
    Sure, go ahead and post the solution. We have room. :)
  • vinettavinetta Member Posts: 5
    have they posted the fix for this pcm problem having the same problem on a 96 jeep grand cherokee laredo.
  • tcollins88tcollins88 Member Posts: 1
    I have a 2003 Jeep GC Laredo and well we can get it to start but after driving about 5 blocks it either tries to die or does and then it goes down hill from that we were told fuel pump but i dont think thats it cause we can get it to idle as long as we dont touch the gas or put it in gear. PLEASE SEND ME THE INFO thank you
  • oldmill76oldmill76 Member Posts: 2
    I have been pleagued with the same symptoms did you find a fix?
  • oldmill76oldmill76 Member Posts: 2
    I have replaced the crank and cam sensor but still nothing. Not getting fire from the coil but it tested fine. Cant just put a pcm in unless i have a good idea thats it. Ive ran all the tests i know to run and need help. It used to make me wait till the pump would pressure up and when it would finally pressure up the check engine light would flutter with it. The relay box would also make the clicking noise along with the fuel pump. It all took about a min for the pump to ingage. Once the pump ingaged and the relays quit clicking it would start and run good. Now nothing ..
  • desert_roguedesert_rogue Member Posts: 2
    I have a 2007 Cherokee SRT8 and recently it has started to die without warning or reason.

    Dealer says the PCM is defective but am not so sure. it seems to be worse when it gets hot and also when the dealer "tested" it by giving it a good hard whack with the palm of his hand with the car running it stopped.
    I believe the PCM will be rated for the extreme temperatures under the hood so I am inclined to think it is a bad contact. Would appreciate to have some info on what you found before I spend over $1,000 on a new PCM which might not cure the issues.

    The only other items I thought bout were the crankshaft position sensors and the camshaft position sensors.

    Any help you can give would be great. it does not suit being a yard ornament, it is meant to run.
  • jeeppoor1jeeppoor1 Member Posts: 1
    2000 JGC 136,000...getting ready to take into the shop that replaced the PCM 2x. This time after a week of getting it back after month of figuring out what's wrong,,,it's RPM runs between 500-1200 when stopped. The car runs rough and will jerk/hicup/jump during acceleration. Also the mileage, while it wasn't the bet before now is 2mpg less then before this all happened. Not sure what they will check for so any input would be helpful from the forum
  • djungbluthdjungbluth Member Posts: 2
    I have had the same problem. After changing all kinds of sensors and ign coil. I found a loose connection at the pcm. it looked fine , but I had my wife start it and I wiggled the plug and it died 3 times. I shoved a piece of cardboard between the antifreeze resevoir and plug. now it runs great.
  • stillfixinjeepstillfixinjeep Member Posts: 1
    My '93 Grand Cherokee was making me wait 1-5 minutes for the check engine light to come on and then prime the pump. It then started to take almost 30 minutes and finally didn't prime at all. Once the check engine light quit coming on, I replaced the PCM with a flashed rebuilt from online. I still have other issues, but now the CE light comes on immediately and the pump instantly primes. Sound like your PCM to me.
Sign In or Register to comment.