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Jeep Grand Cherokee stalling fixed!

by 1996Jeep GC / May 18, 2007 12:44 PM PDT

Found that the outboard PCM cover screw was shorting out the circuit board. Chrysler PCM p/n P56028412, s/n TEH106636023.

Short story long: I have a 96 Grand Cherokee 4.0L, 125,000 miles. Several weeks ago, I started to have stalling issues. Hot or cold, dry or wet, first drive of the day or last, it didn?t matter. The engine would cut out. It felt like it lost all electricals.
At the time it was showing an ASD relay code. Swapped the ASD and A/C relays. Same problem. I didn?t have time to look at it, so I had the dealer go through it. After 2 days and $200, they called and said it was the ASD relay, and that they put in a new one, and it?s all good. Um, ok, maybe I missed something. I?m a trusting soul, but let?s see if this fixes it. The next day the problem was back. I went back to the dealer and they basically said, ?We don?t know what it could be, good luck with that?. Now my wife knows why I don?t go to the dealer. By the way, the old relay tested good.
My turn. Being the methodical aircraft mechanic that I am, I grabbed a multi-meter, contact cleaner, and wiring diagrams. I cleaned connectors, ohmed out wires and sensors, checked for power and grounds. Everything checked good. By now, it?s showing ASD, crank sensor, and primary ignition codes. Then, with my wife trying to start it, I wiggled the connectors on the PCM. Every time I wiggled the gray C3 connector just right it would run. When I let go, it would die. So I took the connectors apart and tightened up the crimps (I don?t recommend doing this without the proper extractors and crimper). Threw it back together and BAM! Same problem. Well, time to bite the bullet and check for bad solder joints on the PCM board. I took the cover off of the PCM and realized that looking through the potting compound is like looking through Guinness Stout. But, I put it back in and hooked it up. It started stronger than ever, and didn?t even think about stalling. Yes! I figured that I finally got the connectors sorted out, so I left it over night to cool down. Got up the next morning and it started right up and wouldn?t stall even when wiggling the connectors. So I put the cover back on, put the PCM back in, hooked up the connectors, and BAM! It wouldn?t start! That was the point when my wife asked, ?How?s it going?? And I, being the methodical aircraft mechanic that I am, said, ?what the ----?? That?s when my wife turned around and went back into the house. While smoking a pack of cigarettes, I thought, ?Gee, it runs with the cover off, but not with it on.? DUH, wonder what it could be? So I backed out the two screws that hold the cover on and BAM! It started right up. Then, while it was running, I tightened the outboard screw and sure enough, it died. Yes! Aircraft mechanics love it when they can make things stop working. I installed new screws (1/4? long, factory screws are 1/2? long Torx head), and she?s been running great ever since.
Now, will this fix a bad crank sensor or idle air motor? No. But it is an easy trick to try before going to the dealer and having them throw expensive parts at your Jeep and seeing if any of them stick. Just back out the cover screws about 1/8?-1/4? (don?t worry, nothing will fall apart inside). If it fixes it, great! Spread the word. If not, use logical trouble-shooting steps. Learn the systems ? what will and what won?t cause the problem. Good luck.
As a side note, if you want to see a service manager?s eyes pop out of his head, tell him that you want your money back because your not going to pay them to trouble-shoot a design defect. It?s a glorious sight.

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pics needed
by Dannywon / June 21, 2007 3:46 AM PDT

We need a pic of this, Please I don't know what the PCM looks like. I have two jeeps, same problem on both. They really suck.

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PCM Location
by 1996Jeep GC / June 21, 2007 2:57 PM PDT
In reply to: pics needed

My Jeep is unavailable for a picture right now, but it's easy to find.
It's located in the engine compartment on the passenger side of the firewall, aft of the coolant reservoir. You will have to remove the reservoir. The PCM is a square metal box mounted vertically to the firewall with three bolts. On the front, you will find three large rectangular connectors, one black, one white, one gray. Beneath the two outer connectors, you will find the two screws. You do not need to remove the connectors. The screws use a #25 Torx bit for removal. Back the screws out about 1/4" and see if that makes a difference. If you have the same problem I did, install two new 1/4 or 3/8 #6 sheet metal screws and your good to go. If not, come back with detailed info and I'll try to help. Good luck, and let me know what happens.

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Screw Locations
by joshbroide / August 26, 2007 8:06 AM PDT
In reply to: PCM Location

I have the same proble with my Jeep Grand Cherokee, it stalls when I am driving the car and at stop signs. I took your advice and removed the resovoir, found the box with the grey, white and black connectors, but I am not sure which screws need to be loosened and changed to the 1/4".
The black box with the three color conectors has two screws on the left and one on the right of the box. I loosened all three of them but they are very long screws. There are two other screws that are located further to the right, one on top of the other, with the nut showing and the bolt located behind the metal.
Am I in the right area?

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PCM screw locations
by 1996Jeep GC / August 27, 2007 9:26 AM PDT
In reply to: Screw Locations

The three bolts you mention secure the PCM to the firewall. The two screws are below the connectors, one below the gray, and one below the black. The heads face forward toward the battery. You should be able to feel them if you can't see them. If you still cannot locate them, remove the connectors and you can't miss them. When removing or inserting the connectors, remember to disconnect the battery ground. Also, there are locking tabs on the top and bottom of the connectors which must be squeezed together to unlock them.

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You did it!!
by joshbroide / September 3, 2007 10:30 PM PDT
In reply to: PCM screw locations

I found the place you described and its been a week since I put in the 1/4" screws. My Jeep GC hasnt stalled once and has never felt so strong. You are truely a hero and my family and I would like to thank you for your guidance.

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No, you did it.
by 1996Jeep GC / September 4, 2007 9:07 AM PDT
In reply to: You did it!!

Thank you for the kind words, but I am hardly a hero. Just a guy who hates getting his butt kicked by inanimate objects. Hope she keeps running well.

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97 Grand Cherokee stalling fixed
by alykat89 / January 11, 2008 10:18 AM PST
In reply to: No, you did it.

I really appreciate your effort in locating this problem. It had
put my family in dangerous situations multiple times when the Jeep would stall and there was no place to pull over. I was just about to
start working on the the connections to the ECM after replacing many
other parts without success. Even had it to the shop twice. I had bungee cords keping tension on the connections leading me to believe that the problem was the wiring. As
soon as I read your solution I removed the screws and reinstalled them with 1/4 inch washers. 10 minute job. Thanks much

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95 jeep cherokee 4.0
by holli0412 / February 23, 2011 9:31 AM PST

my jeep wont start it turns over when you turn the key it gets gas but no fire i replaced plugs distribitor cap and rotor button, the coil, the electonic pick up and the crank sensor but it still won't start. CAN SOMEONE PLEASE HELP ME !!!!!

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by mikeland357 / February 23, 2011 12:27 PM PST
In reply to: 95 jeep cherokee 4.0

My immediate guess would be the PCM but I'm a jackleg mechanic.

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You seem to be the guy to ask
by chessysailor / November 16, 2008 10:23 AM PST
In reply to: No, you did it.

I tried posting this before but wanted to make sure i got it posted in the right place. I have a 2003 Jeep GCL 4.0. At higway speeds it stalls. Not to the point where it has to be restarted. Just bad enough to have to get out of the way and come to a complete stop. After you come to a complete stop or pull of the interstate it drives fine as long as your in town. I am not getting an engine light. I hooked an OBD II to it to see if it had any saved codes and everything checked out ok. It seems to run fine on and off the interstate as long as you have over half tank of gas. It had a little less than a quarter tank of gas when this started happening. The problem seems to happen at speeds over 65 mph. I have already replaced the fuel filter and tried Lucas Injector cleaner. If you have any suggestion that might help me out I would be greatly appreciative.

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stalling at speeds over 65MPH
by jsg13 / December 27, 2010 3:45 AM PST

I see this is an old post, but I had a very similar problem with my '97 GC several years ago. At speeds of 70 mph, it would stall out completely. After sitting for a minute, it would start and run fine. My mechanics looked over everything and couldn't reproduce the problem. Finally one of the old mechanics at the shop said " it's the distributor cap". So this being not much of a risk, I had it replaced and it fixed the problem since. So guys out there, this may be one of the fixes you need.
I have a different start problem now.

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Tried several remedies posted, it took a new PCM to fix it
by mikeland357 / January 17, 2011 8:33 AM PST

I had replaced the distributor cap, plug wires, spark plugs, rotor button, battery terminals, and oil pressure sending unit. I checked and cleaned all the connectors I could find and replaced the Torx screws on the PCM board as suggested in this post. Nothing seemed to fix it for long (a few days at best and a hundred or less miles). I even took it to the dealership and had them take a look. They said I needed a new fuel pump and recommended a new cranshaft sensor; I refused the work because I thought they were full of it; I paid them $85 and left. I ended up buying a new PCM from and called a different dealership; the service manager told me to go ahead and install it but leave the old plugged in in order to drive it over. I did and they flashed it/programmed it for $89, That was a few weeks ago and 500+ miles later it is still running perfect. I discovered that you MUST get a dealership toflash the PCM because of security in order to flash the odometer reading and VIN number. It was well worth it.

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Still fixed.
by mikeland357 / June 27, 2011 10:54 PM PDT

It has been 6 months now and I've driven another 10,000+ miles and it still runs great. The rebuilt PCM was the ticket.

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where on rockauto????
by Banks860 / December 8, 2011 7:43 AM PST
In reply to: Still fixed.

ive been having problems an ive desided im do the pcm an get it flashed an programed. but on the rockauto site i cant find a pcm only a ecm, i know there in the same unit but i dint know what to do, plz help thank you mikeland357

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Update 8 months later
by mikeland357 / September 9, 2011 12:59 AM PDT

I have now driven approx. 13,000 miles on the new (remanufactured) PCM from and it still runs perfect. As I recall, I paid about $210 for the PCM (including shipping and after the core return credit) and as previously stated the Jeep dealer charged $89 to flash it.

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Question about ordering new/rebuilt ECM
by Plasmatico / September 22, 2011 12:06 PM PDT
In reply to: Update 8 months later

I am having the same problem with my GC, and I have narrowed it down to being the ECM/PCM. Now I have found the part I need to order at, but which one should I get? Or rather, which one did you order. They have the option of ordering a reprogrammed one, or you can send your old one in to be reprogrammed. I am unsure and tired of having to deal with this problem. Thanks in advance!

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you might be shocked
by jasonfrix123 / August 2, 2011 9:17 AM PDT
i only have been working with cars a couple years but there is a bottle at your local autozone called seafoam get that bottle and put a vaccum line that comes off the intake into the bottle you will be amazed at what comes out the tail pipe just remember to keep the vehicle running your basicly cleaning the carbone outa the motor
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by collat80 / November 21, 2011 12:57 PM PST

hello i have a 2001 jeep grand cherokee and i have same issues my jeep stalls a few times (that really scare me), and some times engine lights come on and nex day is goin off, i firs think y have problem with my fuel (trash in my gas tank) but after read all this i really think is my pcm, and after read all about the dealers i dont believe on that.... so please i need know if u problen is fixed after you replace u pcm.. thanks

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the fix
by thatguy40 / October 28, 2012 4:41 AM PDT

solution to your problems
My jeep stalled and backfired and died for three months. It drove me crazy. I did everything everyone else did replacing alternator fuel pump water pump crank shaft sensor other sensors i mean just the monetary nightmare. Thene one morning i run into a post on the internet. The guy wanted 20 bucks for the solution. I figured what the hell, whats 20 bucks. low and behold the **** worked. Im still at a loss of wordss... So I'm going to give it to you free today because if your like me I know what you have gone through. This fix is a combination of all the other solutions I have read over 3 months with my problems of backfiring stalling sputtering and the like. takes 30 minutes or less

First unhook the battery cables second remove the overflow tank next on your computer on the firewall remove the three plugs that connect into the computer then you will see the two little screws that people talk about backing out (the screws short the system out) remove the screws one at a time ande add 3 8 mm washers to each screw then replace them. Next take a good electrical cleaner spray and spray the plugs and the connectors where they pug in. Spray them well to insure there clean. Let dry about 10 minutes. then take some dialectric electrical silicone and put on plugs in each hole and then in the connector spots they plug in. (this creates a better seal and connection) Plug the plugs back in. The plugs only fit where they are suppose to go so you cant go wrong. Now that the plugs are in take 24 inch zip cordes and wrap around the computer and the plugs you just plugged in. 2 cords per plug and pull each cord snug to put pressure on the plugs. 2 cords per plug cut off the remaining cord hanging off the cord. When its done. your computer will have 6 zip ties wrapped around it forcing the 3 computer plugs into the system. Thats it..... Simple and works..... I'm still amazed. i paid 20 bucks for this fix. If you cant understand what I just shared with you for free you can go to and pay 20 bucks and see the guys step by step video. I hope this helps somebody out there. Like I said Im only sharing it because my jeep just about drove me crazy and broke me.... The **** worked and i'm still amazed....20 bucks good lucl....

Just a guy that wants to help

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by JjJjJake / June 12, 2013 11:25 AM PDT
In reply to: the fix

I know this was a pretty long time ago, but do you have like a picture of where the screws are or something? Because I can not for the life of me find the derned things. I hope you see this and can respond.

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(NT) Hey JjJjJake! Still need help?
by greenme5 / July 3, 2013 2:45 PM PDT
In reply to: HELP
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(NT) would this work
by jmolina14 / December 14, 2010 1:02 AM PST
In reply to: No, you did it.
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by jmolina14 / December 14, 2010 1:03 AM PST
In reply to: No, you did it.

my jeep 1997 had the same problem how would it work if u just took those screw out and did not put any back would it not have a good ground????

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leave out the screws?
by BHarris / April 14, 2011 4:22 AM PDT
In reply to: hey

Worked for me for 2+ months and then stalling started again.

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You are a hero
by gomezpalma1 / January 2, 2013 9:56 AM PST
In reply to: No, you did it.

My Jeep started having problems very similar to the ones described here. I changed spark plugs and cables, the cap and rotor, the ignition coil, and the starter, but kept having problems. Today I searched the internet for answers. I thought it was something major, or electrical, and I almost gave up. When I read this post, I had my doubts.

I was about to take it to a mechanic, but it would not start, so I figured I had nothing to lose. I found the box but could not take out the reservoir since I only had channel locks with me. I loosened the only screw I can access, and "voila" it started right up. (knock on wood) It is running great.

If I knew where you are, I would send you a nice bottle of Whiskey.

You are a hero for spending the time to trouble shoot the problem, but more importantly, for sharing it with the rest of us.

May God bless you and your loved you these coming years.


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You did it with 1/4 screw
by kwsuccess / November 20, 2012 9:05 AM PST
In reply to: You did it!!

This lasted for a long time, but now the problem has reared its head again; although mildly. Mildly, is the way it started before. CPU codes are: Misfires #5 & 6.

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URGENT - Still Can't Find PCM screw locations
by ljulian / December 30, 2007 8:11 PM PST
In reply to: PCM screw locations

Hi All you Lucky people,

I have read this forum twice over again because I have the same stalling problem -- exactly as described -- with my 2002 Jeep GC Laredo (90K+ miles). Right now I am in an urgent situation. The urgency is this -- it was towed to the Jeep dealership on Saturday and I don't want, nor can afford them to look at it and say I need a new PCM board.
My friend and I followed the directions to the letter:
removed the coolant container
removed Battery ground wire
removed the Grey, White, Black PCM connectors (in that order, left to right)
Cannot see any screws below the outer connectors. Can find only one hard to reach possibly T25 head which is below and to the left of the Grey connector. Can't get to it.
Please help me locate the screws for my 2002 JGC. It seems to be so worth trying.
thanks all,

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by ljulian / December 30, 2007 11:37 PM PST is stating that this time it's my crank shaft. Oh well, there goes another $200+.

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Crank Shaft
by joshbroide / December 31, 2007 3:44 AM PST
In reply to: nevermind...

What is the crank shaft?

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The crank shaft
by Andy77e / January 1, 2008 1:23 AM PST
In reply to: Crank Shaft

Is the most important part of the whole engine. It's also the most impossible to get to. Most of the time, it's almost cheaper to replace the whole engine, than to replace a crank shaft.

However it's also one of the least likely parts to break... one wonders how it would be damaged unless it was run without proper oil changes.

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