More electrical nightmares - 2006 Volvo vnl 670

use voltage probe, better analogue voltage probe to find points of voltage drop

weak contacts usually go hot when u try to actuate starter

 

I am having somewhat of the same problem. I apologize for replying to your issue with my issue but i cant figure out how to start my own "Post". My issue is this; My 2004 volvo 670 ISX Cummins is having major idling issues. When i try to idle up when parked the idle increase will stick and then after a moment will fall back down and then become erratic. Then , when i stop at a red light, my constant idle is so low that my truck will stall out at times. This is a problem that just started within the last few weeks. I am getting the following codes; Idle Validation Switch- Electrical fault, Accelerator Pedal Position %- Mechanical, Output Shaft Speed to high- Electrical Fault, Cruise Control and Retarder Switch Supply- Electrical Fault, Pedal Switch(es) Supply- Electrical Fault.. ............... I am leaning towards it maybe being a harness but as for tracking it down i would have no idea as to where i should begin. Hoping someone on here may have an idea as to what could be causing this.....Any theories help. THANK YOU

 

Sounds electrical. Carefully check all power and ground connections. Also, watch for a fuse in the battery box supplying power to the ecm. Check and clean if you find it. It's likely going to be subtle, it won't look like a problem til you take it apart, or unhook it whichever type of connection. Best of luck.

 

I didn't even think to check the fuse. I'm going to go check it after I eat. Thanks man, I really appreciate it. I will give you an update after.

 

Hmm... Idling problems with a code for idle validation switch.

Sounds like a good place to start.

 

My 2014 670 isx 15 had so many problems lately. I found a 150 amp buss fuse that was bad. Seems to run fine after I replaced the fuse. I love Volvo trucks

 

Where in the world did you find a 150 amp fuse?

 

under cab where batteries is.