Bad PCM?
 

I have a 2001 Cherokee sport. A couple days ago started stalling out on slow speed acceleration. Was not running rough at speed or idle at the time, but later had trouble starting when problem was occurring. I did some searching and symptoms seemed to indicate Crankshaft position sensor. At same time Oil pressure sensor started reading super high non stop. Replaced both OPS and CPS after confirming code with neighbors code reader while problem was occurring.

After a short test drive problem is back, now code reader is saying camshaft position sensor, and the oil pressure gauge is not working. Question is, should I throw another hundred bucks at a camshaft sensor or am I looking at a bad PCM?

What are the code number(s)?

I didn't catch the numbers, but unit said "Crankshaft position sensor" yesterday, and "camshaft position sensor" today, as well as the oil pressure sensor today after the gauge stopped working.

P1391 for the crank sensor

I'm dealing with a bunch of weird codes on my '01 Cherokee, crank sensor, cam sensor, coil, misfires. Three times it was temporarily resolved by replacing the crank sensor. The fourth time just happened last week. Yesterday I think I fixed it by running a ground cable from the stud on the engine block (that the battery ground cable attaches to) to the upper starter mounting bolt. This gives a direct ground path through cables from the battery to the bellhousing (the crank sensor mounts in the bellhousing so that gives a good ground to the crank sensor as well as the starter). Time will tell if that provides a real long-term solution, and I certainly don't know that it's your problem. But it cost me about $11, so it's probably worth trying.

Here's the thread on my issues. And if it's not the ground, be thankful you've got CCKen's attention. He provided me with a lot of good advice.

https://www.cherokeeforum.com/f2/cod...1391-a-199384/

The PCM should the last component to replace if everything else has been absolutely ruled out. Furthermore, anyone who pays $11 for any sensor should be prepared to replace it again very soon. Aside from throwing away money, the main issue with going cheap is you end up spending more money on components which may be totally fine but can't be ruled out due to the first piece of crap the fails intermittently.

P1391 is intermittent loss of EITHER the crank sensor or the cam sensor circuit.

If you replaced the crank sensor, I'd suggest testing or "indexing" your camshaft position sensor. Search for "toothpick indexing" technique. If you do end up buying a cam sensor, please do yourself a favor and buy a genuine MOPAR cam sensor from Jeep. Aftermarket cam sensors are extremely "hit and miss" with a lot of miss.

The oil pressure issue is likely not related to the above. Have you verified the wiring/connector leading to the oil pressure sending unit?

This does not sound like a computer issue to me. I think you have 2 separate issues.

$11 was for a ground cable to go from the engine block (where the battery cable attaches) to the starter. My point being that even if improving the ground connection doesn't solve the problem on someone else's vehicle, at this point it looks like it did on mine. And if spending $11 on a ground cable might fix it, why not try before throwing more expensive parts at it?

Wiring issues, is this a flood vehicle?

Sorry, misread your post.

Like tjwalker said, the CMP should be suspect. This is not new with the '00/'01 XJ's.

But, before doing any parts changing do some visual inspection of the wiring harnesses.

The CMP and OPS wiring are contained in a short run of harness that merges into a larger harness that runs behind the rocker cover, then on to the PCM. The CPS wiring is also contained in this harness loom.

Inspect these harnesses for penetration of the loom and into the wiring.

The reason I suggest inspecting the harnesses is the Oil Pressure has been acting up as well.

Also, physcally reposition the looms and wiggle them to see if makes any difference.