Yimtoung

Hi guys. I have a 2004 Grand Cherokee. My wife was driving it a couple of weeks ago and it died. The fuel gauge went to empty. I added fuel thing we had our tank cyphered. still no go. Had it towed home and replaced the CPS and camshaft position sensor. The old CPS tested bad. Still no go. Where should I check next?

Yimtoung

I replaced the cam shaft position sensor again. This time the jeep started and ran ok. The dealer ship said the the position sensor for the 4.0 was discontinued. Found one on Amazon. That did the trick.

Yimtoung

The gauges went to zero again while driving. Vehicle shut off and won't start. Replaced the cam synchronizer unit which came with a sensor. The gauges stayed at zero. This is frustrating to me. Does anybody have any suggestions?

Moeron

I've had the gauges go dead from the door panel (not screwed in at the time) shifting and all the gauges went zero. A simple attitude adjustment to the door panel and they all lit back up. 97 ZJ

Yimtoung

Did the vehicle shut off when this happened? Mine won't run.

Moeron

No, this was on the road, vibration shook the panel some, gauges went out, bang on the door, gauges came back..

Yimtoung

Thank you for the suggestion. I will check the door panels.

Moeron

I'm struggling with my 97, also won't start. Jeeps have a startup sequence of sorts.

When you first turn the key ON, it more or less takes you at your word that you think the engine should start normally, for a couple of seconds anyway. It will activate the ASD and Fuel Pump relays so you get some fuel pressure.

When you then turn the key to START, it will obligingly permit the ignition to generate spark, and activate the fuel injectors as needed for the cylinders.

For most people, this is enough, the engine starts, and off you go. If however, the ECU isn't receiving certain signals (crankshaft position and cam position) within a second or two, to convince it the engine is running, it will deactivate the ASD relay, turning off the fuel pump relay, and stopping the spark.

I've replaced things here and there, and finally narrowing it down towards my fuel pump. I get a relay-sounding thunk noise from down there, but no pump hum and no fuel pressure. I don't look forward to possibly having to drop the tank.

Yimtoung

This all started in March of 2023. Running now! I replaced the crank shaft sensor and cam position sensor twice. The throttle sensor once. Was able to get an electrical schematic for the vehicle and was able to troubleshoot the PCM had failed. The PCM was replaced. Once the PCM was replaced, the Jeep started and ran fine for one day then started running rough and misfiring. While troubleshooting the miss firing, I noticed a noise coming from the alternator. The noise would get louder just before the miss firing started. I pulled the alternator and had it tested at O'Reilly's auto parts. The alternator made loud noised while being tested but according to their tester, it passed. Replaced the alternator and the crank shaft position sensor again. The jeep started and is running ok. I had an alternator issue on another Chrysler vehicle several years ago that caused the transmission to shift up and down randomly. When the alternator was replaced, the transmission issues went away. I still have that vehicle and it is running fine. Chrysler alternators seem to have issues that cause various problems with the vehicles electrical systems. Hope that this helps others with their jeep issues.