2003 Jeep
 

My 2003 Jeep Cherokee Laredo will crank up fine and run for a couple of minutes, actual time varies from a few seconds to about five minutes. Then it suddenly dies as if the ignition has just been turned off. Any ideas? It was suggested to me that it might be the ECM. Is that expensive?

Re: 2003 Jeep
 

Stock used ecm is less than $50. Your ecm receives an ignition signal which grounds the relay to your fuel pump. This is all fed through your ignition key and circuit. Your engine is dieing because its not getting fuel or spark: you just have to figure out which one.


1. Monitor the ignition feed to the Powertrain Control Module (PCM) on the Dark Blue/White wire at pin 2 in the black connector.

2. If losing the feed to the PCM, check the ignition switch. Monitor the voltage on the Dark Blue wire and the Red wire. If losing voltage on the Dark Blue wire but not the Red wire, the ignition switch is bad.

Playing the odds-its almost never the ECM. If I were to blatantly throw parts at it with out properly diagnosing the problem...but a new Crankshaft position sensor...this will be the culprit 50-75% of the time, then your ignition switch, then possibly fuel pump (check fuel pressure at rails at idle and load), then maybe PCM (computer) or bad wiring, ignition system ect...

Number 1 replaced part on that Jeep is the is the CKP (crankshaft position sensor)



Get you truck scanned for pending codes...this will tell alot more about any problems.