Hi all, I was driving on the highway at 55 mph and my Jeep died. It has fuel pressure, but no spark. I checked the coil and the resistance values are good. The rotor in the distributor spins when cranking. I toggled the key 3 times and got these codes; 12, 41, 35, and 33, and of course 55. I have been having issues with the alternator not charging properly all the time lately as well. I read that the caps in the pCM may need replacing, or the crankshaft position sensor. Any help with these codes will be greatly appreciated.

 

http://jeep-xj.info/HowtoECUcodes.htm

 

Disconnect battery wait half hour reconnect try starting then read codes again. my 94 stalled once what had happened cps in dist had rotted apart got lucky removed cap and wala there it was ....

 

Thanks for the link. I did run across a code list earlier. The 12 makes sense, I did a battery swap recently. I'll disconnect the battery in the morning, then reconnect after half hour and get the codes again. I'll also check the cam position sensor. We didn't notice anything visually when I pulled the cap up and cranked it to see if the post rotor thingy<--- turned. Thanks again. I'll post what the problem turns out to be.

 

Crank sensor is a primary suspect. Start by checking all major fuses. Here's more on the route of spark for your XJ. The code 41 is almost always caused by a faulty alternator.
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Spark: 12 volts from ignition switch to the ASD relay; when the key is first turned on the PCM provides a ground to the ASD relay to energize it, then the ASD relay passes 12 volts to the coil primary side. If no crank sensor signal is generated after a couple of seconds the PCM cuts the ground to the ASD relay (and fuel pump relay too) and that cuts power to the coil (and fuel pump). Key to START and once again the PCM energizes the ASD relay. Now, a critical element is the crank sensor--no signal from the crank sensor and the PCM won't trigger the coil to provide spark.

 

tjwalker, thanks. I checked the fuses and swapped a couple out for the ASD relay. No change. That code 41 has me thinking about the alternator, which I have had problems with lately. My volts register only about 10-11 volts on the gauge. It should still start since the battery has a charge though, right? Would removing and testing the alternator be a waste of time? or should I check the crank and cam sensors first? I'm going to reconnect the battery and read the codes again in about 15 minutes.

 

I reconnected the battery, and got 12 and 55 for codes. I then tried to start it...crank,crank,crank, no fire. Cycled key again and got 12, 41, and 55. According to the posted link above: Alternator field switch. Switch not operating correctly and check charging system. I'm going to price a Crankshaft Position Sensor.