This has happened a couple of times now. Driving along at surface street speeds (25-35 MPH) and the engine "stumbles" a little but quickly returns to normal operation and the check engine light comes on. Had the code checked and P0121 was the only code. Anyone have experience with P0121?

 

Accelerator Pedal Position $en$or issue.

 

You can try resetting it and see if it helps.

https://www.dieseltruckresource.com/...n&onlynewfaq=1

Usually it bandaids the problem for a little while, lets you save up for a new APPS.


phox

 

Exactly where do I find this APPS? I was told by some one that the trucks with manual transmissions did not have an APPS. Is this true?????

 

It is mounted to the engine, up near the injection pump.

Yes, all 24 valve trucks have an APPS.

There is no direct connection between the go pedal and the engine, it is "fly by wire", all electronic.


phox

 

This is sort of related, just thought you'd like to know for future reference:

http://www.i-hacked.com/content/view/95/45/


Maybe I'll make a seperate post of the i-hacked.com link too.

 

I'm getting a P0016 What does thet mean?

 

As near as I can tell, all OBD II DTC's start at 0100....are you sure the 0016 is correct?

 

Uh, oh. I hope it isn't P0216 (Injection pump timing control failure)