Series 60 Detroit DDEC3

Flash codes then a scan tool.

 

When did this problem start ? or is there any more info to point us in the right direction ?

 

You may have a fuel pressure issue Maybe injector Orings or even dirt got into the fuel Galley ?

 

Okay this Means i need to look at your program then

 

My yellow CEL doesn’t work either. Without the stored codes, it’s hard to tell. I was able to catch a problem while it was happening, and got the active codes. Actually the code was intermittently active, for low coolant. I had to determine if it was the sensor, or the harness. Got lucky and caught it while active. Maybe try to get the codes while it’s running rough. If there’s any active codes, they should flash. I’m sure you know that code 25 means no codes.

 

The only thing I can think of is the cruise control circuit - clutch switch and brake switch need to be off for cruise to work, and I would guess the sensor on the park brake circuit ties into it too - and there's been a splicing of wires or rubbing of wires that feed to the ECM that's messing it up.

Is it your truck? Has there been any wiring work done? Inspect the harness pretty closely, or maybe try a test ECM if you can source one.

Not a mechanic, but that's all that comes to mind.