1999 Xj cuts off cel resets itself

I've been having this issue since I got the jeep. Every now and then the engine light resets itself and my jeep shuts off. When it rains it doesn't want to run at all. This thing is making me want to trade it in. I have been a mechanic for a long time and this thing is stumping me. When it acts up randomly it will shut off every time you make a right hand turn. I don't have a lot of money to throw into this thing so I'm hoping someone can help me out with this.

It is a 99 Xj with 4.0 auto 4wd

Explain "the engine light resets itself and my jeep shuts off".

Is the Check Engine Light ON ?

So you have a cel, and then it disappears after the jeep stalls? Bad battery terminals or grounds somewhere if that's the case.

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Went over all the grounds and has new battery and terminals. I'm thinking it is the computer but was hoping some one had the same problems before I spend the money on a new computer.

It also throws the same codes all the time p0340 and p1391 which are cam sensor codes. Has a new own distributed and I ohmed the wires from computer to distributor and all is good there

PCM failure is very rare. Problem solve for the trouble codes. The right turn shut-off and rainy day issues very strongly suggest wiring/wire connector/ground issues Suspect that the cam sensor needs to be synchronized. Read this -> http://jeep.blackonyx.net/pdfs/jcss.pdf

P0340 JEEP - Camshaft Position Sensor Circuit

Possible causes

- Faulty Camshaft Position Sensor
- Timing chain stretched or jumped
- Camshaft Position Sensor harness is open or shorted
- Camshaft Position Sensor circuit poor electrical connection
- Dead (Weak) battery


P1391 JEEP - CMP or CKP Signal Intermittent Condition

Possible causes

- Faulty Camshaft Position (CMP) Sensor
- Camshaft Position (CMP) Sensor harness is open or shorted
- Camshaft Position (CMP) Sensor circuit poor electrical connection.

Potential Fixes:
Fix #1:
Inspect your wire harnesses for damaged wires, chafed insulation, or failed wire splices. Use a volts/ohms multi-meter to check the resistance of the ground wire circuits from each sensor. Replace corroded ground wires/connectors and clean ground wire connection points.
Fix #2:
Timing may off. Re-index the distributor/cam sensor per the FSM instructions, or replace faulty distributor/cam sensor pickup module.

A mis-indexed distributor/cam sensor may exhibit surging, light bucking or intermittent engine misfiring. This will most likely occur when the vehicle is at operating temperature and under a light load at approximately 2,000 rpm. The proper indexing procedure must be used as outlined in the service manual.

Notenoughboost1 said:

I've been having this issue since I got the jeep. Every now and then the engine light resets itself and my jeep shuts off. When it rains it doesn't want to run at all. This thing is making me want to trade it in. I have been a mechanic for a long time and this thing is stumping me. When it acts up randomly it will shut off every time you make a right hand turn. I don't have a lot of money to throw into this thing so I'm hoping someone can help me out with this.

Click to expand...

Looks like a exposed wire in the harness, shorting to power or ground when moisture is present or engine movement is involved.

Take a look at these photos. Possible problem area.

I went through somethin like this with my zj. Is it like you turned the key off? No gauges or lights? For me it was the battery lead to the starter had gotten worn down into copper and was shorting agenst lca. Cost me a pcm ( 300 reman. Was on my 5.9) just start poking and pushing at the harnesses while it's running and you will find the issue. If it's only right turns push towards the driver side a bit but still move it all around.


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Yes all the gauges shut off also. Only the radio stays on. I did find some wires that were melted together last night. I fixed the wires now just have to wait on some rain to see if it still acts up. Thank you everyone for your responses and I will keep you updated

Problem locations for 97-01 XJ;

CAM sensor connector
Driver door to body
Hatch to body

This has been my experience.

Good luck!

So far the jeep has been fine. We had a huge storm yesterday and it did not cut out at all. Thank you for the quick responses and help