C 15 Accert throwing a code

55 I thought meant no codes all clear. but I have been wrong before. maybe a short for a second but not long enough to store the fault code.

 

55 means everything is good at the time you check it.

 

So everything is good, and it derates the engine just to be funny?

Or does it think you want to check for codes and slows ECM functions while checking?

 

Just looked in my book to be sure. 55 is no codes found. Not to say u don't have a problem. Its just not throwing a code.

 

Next time it does it and the light is blinking you need to take a snapshot to get the ecm to log it. If I remember correctly you just hold the resume switch down for about 5 seconds and it will log it.

 

check the sensor for low water. it will derate it but not throw a code. if it derates again with no code just unplug the the harness from low water sensor and it will run just fine until you get a new one.

 

To trigger a snapshot, you need to make sure the cruise control switch is in the off position, then hit resume, immediately followed by set *or* hit set, immediately followed by resume. Either sequence will work. The snapshot will contain all the operating data for the 30 seconds prior to, and the 10 seconds after triggering the snapshot. A total of 4 snapshots can be stored in the ECM. The most recent of the 4 will overwrite the oldest if more than 4 snapshots are triggered.

 

Great info. I have always wondered how to do this.