Junkyard Cars

i looked all around on cf and found zero related pcm problems for any XJs, ive replaced every sensor on my jeep and checked everything related to fuel. and have zero changes. still stalls randomly, and yes all grounds cleaned and checked, wires replaced whole 9 yards, i have seen the exact symptoms all over the net for grand cherokees but none for xjs, i see they have pcm connector issues, wonder if its the same for mine or im i just a rare case? any help would be nice. 00 jeep cherokee 166xxx miles auto limted. at the point where im giving up on jeeps and the forum. had to put a holt on my build because of this. Thanks guys help me out on this

CCKen

The PCM is mounted on the left front inner fender next to the air filter box.

Are you getting a Check Engine light on? Does the CEL bulb work when you turn the key to run, just prior to cranking the engine?

Have you gone to an auto parts store to have any codes read?

Just exactly what are your symptoms?

The PCM may be bad but you need to do some trouble shooting before shotgunning it.

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Junkyard Cars

thanks for the reply!! cel come on as normal when starting the engine, i just recently checked for codes the other day and nothing but a incomplete 02 or not ready, and cat. my symtoms are stalling at idle and driving and at full thottle, does it when swtiching to reverse sometimes, runs fine other than stalling idle is normal, no cel lights while driving. and something i noticed is once it stalls i cant start it right away, i have to wait until like 5 10 seconds and it fires up everytime. any thing else you need to know?

CCKen

What were (all) the code numbers?

Need specific codes to look them up in the diagnostics manual. The interpretation of codes given by a scanner or code reader are often misleading.

What sensors did you chnge?

What wires did you replace?

Have you checked your fuel pressure using a test gauge?

Junkyard Cars

i didnt see any codes just a not ready on the 02 and a incomplete on the cat
changed the ckp(cmp), replaced battery wires, cleaned grounds, seems that the battery wires have corroded since then, i have fuel tested it with the rental tool from a parts store has 48psi around the board. im just stumped i dont want to take it to a dealership.

Rockfrog

Did you clean the TB and IAC? check function of the TPS (or replace it since it cheap)?
What is the battery voltage engine off, and engine on?
Another thing to check is the coil rail, issues on all of the above will generate the symptoms you describe.
And did you replace the Cam sensor (CmPS - side of engine where distributor would be found) or the Crank sensor (CkPS - in bellhousing) you kinda referenced both.
There has been issues noted regularly over the years with cheap sensors specifically the crank sensor ... Many are bad out of the box. But the crank sensors in the later models are far less problematic than the earlier years. Not infallible but less of an issue (still rolling on my stock crank sensor without issues myself). Test the old sensor if it was the crank sensor, if it test good, move on to the next suspect.

CCKen

What kind of a device are you using to retrieve codes that doesn't give codes. Even without a CEL there could be pending codes.

FP is good.

It may be a Crankshaft Position Sensor. They have a bad habit of going bad when heated.

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havent cleaned the tb and iac, didnt think those would effect the stalling issue more of a idle problem for those, i could be wrong. battery voltage off is 12.6 and on is 12.2, havent checked the coil rail yet and when i do what should i check for?. and i only replaced the ckp not the cmp, bought it from napa which i work at. and but it on and no change. thanks for the reply as well.

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one of my buddies works at a dealer and does inspections. not sure what tool it is. but im a nascar technical instiute student so i will have to see if i can use our scan tools and maybe throw a scope on it. i just dont see why a crank sensor would be bad out the box. and i starting to think my pcm isnt the problem because i had my jeep running and started shaking and wiggling connectors and wires coming from my pcm and nothing. so im going to cancel that out.

CCKen

There have been MANY cases of aftermarket crank sensors bad out of the box. OEM sensors have proven to be the most reliable, although expensive, they are worth using one.

If your buddy works at a Chrysler dealer they will have a DRB III tool that can pick fly $hit out of fly pepper. See if you can have him check out your Jeep with it.

A scope won't help in your case.

There have been cases where the PCM wiring was defective, but most of the PCM faults are internal.

CCKen

Since you have "incomplete 02 or not ready, and cat.", it wouldn't hurt to check the O2S heaters fuse in the PDC, marked O2S RELAYS in the pic below.

Inspect the before CAT and after CAT O2S wiring.

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i think im going to do some diagnosis this weekend. and if i dont come up with anything im just going to suck it up and take it to a chrysler dealer and let them tell me whats wrong with it. probaly will be something small hopefully it is just a faulty crank sensor. i will update the work i do to it over the next couple days. and if you have any thing else you can think of please dont hesistate to let me know something thanks.