Jeep Repair Problems? Ask a Mechanic for Answers ASAP
Key on engine off - all service lights turn on - ABS, etc... they all slowly cycle off check engine light is steady and then shuts off in about 10 - 15 sec
P0108 Map Circ High Input
P0320 Ignition engine speed circ malfunction
P0351 Ignition Coil primary and secondary circ malfunction
I appreciate your suggestion, but my problem was not the grounds. After countless hours of checking the grounds, the voltages, the fuses, the relays, the sensors and replacing hundreds of $ in parts - I have finally found the problem.
IT WAS THE WIRE HARNESS THAT CONNECTS TO THE PCM .
In a 98 Jeep Grand Cherokee it is located behind the coolant reserve tank, and it appears that the electrical connectors pull down over time causing a bad connection. It randomly connects and disconnects and causes all sorts of problems with reporting codes for the system. After a while, I thought that there had to be a problem behind the COIL since I had already replaced the ENTIRE ignition system (coil, wires, plugs, rotor, cap , Ig switch, distrib, etc...) but the PCM was reporting a coil circuit failure. I had even suspected that the security system might be the problem. My stalls slowly increased over time and were worse in warm weather (I live in FL) but didn't follow a regular pattern.
Anyone who might be reading this: The easiest way to test if this is your problem is to wiggle the harness with light pressure at the PCM. I ended up wedging a spacer between the front of the PCM and the underside of the electrical connector (which is "L" shaped) to push it up in to place and then fastened the spacer to the PCM with a large ZipTie.
I did a search on the web after I figured out what the problem was and found the following link about 3rd from the top - they have alternative suggestions and credits (I wish that I would have found this post $1000.00 ago)
"The Fix: (as unbelievable as this sounds, but reported to have almost a 90% success rate from around 45-65 people)BACK THE SCREWS HALFWAY OUT ON YOUR PCM COMPUTER COVER.Then try to start."
This is apparently a relatively COMMON problem on aging Chrysler products with this type of electrical connector at the PCM. I hope that this information is helpful to others out there who may find this post - God is good and Angels are real! Thank you for watching over me -Customer11/2008