My 2003 Jeep WJ with a 4.7L engine runs well until it gets warm. After that, the tachometer jumps around, and the engine dies, but all the electrical parts, like the CD player, still work fine. If I restart it and let it idle, it dies again in about 30 seconds. If I let it cool down, it runs fine until it warms up again. The only code I see is P0320.
I replaced the Crankshaft Position Sensor (CKP). It was stuck, so I had to pay a shop to remove the oil pan and push it out from the inside. They put it back together with the new sensor I got from AutoZone, but the same problem is still there, and the code is still P0320.
I have a new Camshaft Position Sensor (CMP) from AutoZone and know where it goes. Any tips on how to reach it? Can a bad CMP cause the P0320 code? Will it be as stuck as the CKP? I’ve read that aftermarket sensors can be bad. What do you think?
Here’s a picture of my Jeep at a random spot near home in the San Juans. Thanks for your help and suggestions!
There might be a chance that the PCM isn’t picking up the CKP signal because the new part you installed is faulty. Just because it’s new doesn’t mean it works. You could try a different one and return the bad part so you don’t lose more money. Just a suggestion!
I didn’t clear the code after replacing the sensor. I thought disconnecting the battery for a few days would reset it, but a quick search showed that OBDII codes don’t reset just by disconnecting the battery. My mistake! Yesterday, when the Jeep died, the Check Engine Light turned on. When I scanned it, P0320 was the only code there. I cleared that code after reading it. I’ll drive it some more until it stalls and see if the P0320 code comes back now that I cleared it on purpose.
I’ve had some minor issues lately and have read and cleared other codes, like needing to replace the O2 sensor and a small “evap” leak. The first time the Jeep stalled, that’s when I saw the P0320 code.
I figured out the exact condition that makes it stall. Off a cold start it runs fine. 15 min of driving, then idling in driveway for 10 min, then driving around for another 5, no problem. I even tried wiggling all the wires and connectors before I shut off the ignition. I then let it sit for an hour. Started it back up and it died within a few minutes of idling. The Check Engine Light is back on and it won’t start until I let it cool down. The pattern seems to be that it stalls and throws the code if I start the Jeep warm and run it. I’m sure tomorrow morning I could drive it to work, let it sit the entire day at work cooling down, then drive it back home at the end of the workday. I’ll stop by AutoZone to pull codes tomorrow on the way in to work tomorrow to confirm, but I’m sure it’ll give me that P0320.
I agree with trying another sensor first. Just so you know, a magnet can make that sensor useless. When I worked on my engine, I ruined the cam sensor by putting it in a magnetic tray for a little while.
Thanks, Carl and Logan. I’ll try another CKP sensor. I’ll get one directly from a Jeep service center instead of an aftermarket part to make sure it’s good. Swapping it out should be a lot easier this time since the old one isn’t stuck. Honestly, I’m halfway happy just knowing how to recreate the issue. You know how that is…
I replaced the Crankshaft Position Sensor (CKP) with a new Mopar OEM part 56028666AA, which is meant for the 4.7L WJ models from 2002 to 2004. Unfortunately, I’m still having the same problem as before.
It sounds like you should check for wiring issues. There’s a big bundle of wires that runs behind the passenger side head, and that could be a likely spot for problems. I would suggest getting a service manual to test if you’re getting voltage at the connector. You could also check if the signal wire is working with the PCM by following the procedures in the manual. I might not be completely right, but that’s what I would look into next.
I’m experiencing the same problems as the original poster and wish I had read this thread before spending four hours replacing the CKP sensor (though I could probably do it in about 30 minutes now). The P0320 code is still showing, and the engine cranks but won’t start. I bought the CKP sensor from a Jeep dealership. I’m going to try replacing the CMP sensor tomorrow, hoping for better results. After spending so much time and money on the CKP, I’m not feeling very hopeful about this situation. I love my Jeep, but times like this are tough.