Archived Lost power APPS problem??

[RNixon]

My loss of power problem is baaaaaaaaacccccccccckkkkkkkk



Started happening again last night (3 times, and again this morning) Check engine light comes on at the moment the power drops off. Code set is P0121. Same as before. "Accelerator Pedal Position Sensor Signal Volts Do Not Agree w/Idle Validation Signal" My OBD-2 software calls it "Throttle / Pedal Position A Circuit Range /Performance"



Tried to find a replacement APPS today, but no luck. Does anyone know a good source? I did find one reference to Hoesli Diesel. Part number is 53031575 (stamped on the part) I know from last time Dealer wants $455 for one.



Is there anything else I should check before replacing APPS? Just installed new lift pump last time this happened (less than 1 month ago) New fuel filter installed today. Old one looks normal. No other symptoms or problems noted so far. Truck runs great except for these incidents. '99 model with 130k miles.



Any suggestions??

 

[Neal Cassady]

Latest issue of the TDR mag has some info on drilling a hole in the APPs and spraying in contact cleaner to try to restore function. It is in the 24 valve section.

 

[RNixon]

I saw the thread on that. Didn't get the impression that it was likely to help.



I have now concluded that the APPS really is bad, and ordered a replacement from Hoesli Diesel. Good news from Eric there is that the problematic APPS rarely causes the engine to stall. It just loses power for several seconds, then comes back. When this happens to me, it feels like the system is doing some sort of reset after an error.



One interesting tidbit. I called Cummins in Houston for the part. The person I got there told me the APPS does not come from Cummins, but is put on by Dodge, so Cummins doesn't have the part. On the other hand, Eric at Hoesli Diesel told me that he sells these things all the time, and they definitely DO come from Cummins.



We'll see how this works when I get the new part in a couple of days.