M5660SU won't throttle down

[Jack Frost]

My unit is about 6 years old; well maintained; for the last few months, it will not throttle down. When it starts, no matter where the throttle lever is, it starts at full power. The pedal on the floor moves freely. Moving the throttle has no effect on the RPM's. Before I go to the trouble of loading it on a trailer, any thoughts where to start? TIA

 

[Fedup]

No authority on common rails systems but I would start with a service manual and investigate the throttle position sensor values and the related circuit. The computer could be getting a signal that the throttle is indeed wide open and reacts accordingly. I would locate the sensor, unplug it and see if it will even start with that out of the loop.

 

[North Idaho Wolfman]

Check all of the linkage:



Look in the WSM how to test this switch: