jeeponthefritz

Okay fellow Jeepers... We have changed the cam shaft sensor and crank shaft sensor on our 2000 Jeep Grand Cherokee 4.7 and still have the P1391 code. The mechanic working on the vehicle wants us to install a PCM. We really don't believe this is the solution as she runs VERY well. We just have this silly code and the engine light is on. We have read many different scenarios from many different Jeepers. And I understand that it is very hard to diagnose through a computer. Just can't justify installing a PCM without a better troubleshooting from the mechanic. Any and all advice and comments will be greatly appreciated.

97grand4.0

do you have a scan tool? try clearing it yourself? You do know these parts are MOPAR only right? I say bah to the pcm as well.
OK another thread has this..Looks like cheap non mopar parts will do it. When mine went I did as you did, cheap parts, chased gremlins for a week then went to the JUNKYARD and got a cam sensor, cured all the problems and ran great. In fact that same cam sensor I still have after 2 years. Crank I did go to the dealer for.

jeeponthefritz

I am glad you think like me! We have scanned it. Cleared it. Reprogrammed it. Good for about 90 or so miles and BOOM engine light back on with P1391 code. Mechanic doesn't believe its the timing (even though that is what the code says) and wouldn't change the wiring harnesses. He also got two new sensors even though we installed them and still has the code and will not clear. We have installed in total 3 cam shaft and 3 crank shaft sensors and the CODE and dumb engine light still haunts us. Crazy thing is again she drives WELL. Totally stumped. The only other thing I forgot to mention here but mentioned it to my "finance" was the negative side of the battery terminal. He said he had to keep tightening it. Well I am wondering if it is causing this problem?

We did install Mopar parts.

Thoughts?

P.S. Thank you for your reply!

dave1123

Okay, I'm going to say clean and inspect all the connectors for those sensors and for any chaffing or bare wires. The signal returns from those sensors are in the micro-volt range so a poor connection could be causing it to go intermittent. Make sure all of the pin sockets haven't pushed out the back of the plugs. Just recently another poster had that problem with an idle air control motor.