Reset APPs or ?
 

Howdy folks,
While coming home this morning, I noticed that my truck was "surging" while going uphill and the cruise control engaged. At first I was thinking that the clutch could be slipping - it has about 191K miles on it. I disengaged the cruise control and would hammer it going uphill and I noticed the (light) surge. It wouldn't do it unless I was going uphill or otherwise loading it up.
Once I got home, I pulled codes using the 3X key method. It returned 2 codes - P0122 and P0463. The 463 is expected as I have had nothing but problems with the fuel sending unit on the Aux tank. The P0122 was not expected as the MIL was dark. The funny thing was that my code scanner (OBDII compliant) did not find any codes. I cleared them anyway, and the truck "dinged" to signal that it had received a command.
So, where to go from here? I may try the APPs reset procedure I printed out from the FAQ's, but that won't happen until I get up to go back to work tonight, and providing I can roll out of bed 30 minutes early (long, hard 12-1/2 night shift).

I'm too tired to look it up but if P0122 is an APPS code a reset will not help, you will need to replace it, if your ECM records it as a fault it has failed, do a search for Timbo, he has one for 160$ delivered, its more robust and a fraction of the cost if you buy one from a dealer or aftermarket

read this link and you will see why the OEM is a bad designed switch

http://www.cumminsforum.com/forum/98...ps-sequel.html

I just put a Timbo's-Williams TPS on my truck also put on a BD noise isolator at the same time.
Now my truck runs great ! I was doing the APPS reset every couple months till it no longer did anything for the surging, cutting out, jumping out of lock up.
New APPS(TPS) Fixed it.





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Found it, I think....
 

After performing the APPS reset, the code cleared and stayed gone. I think that it may be a coincidence, but last week after I jump started a tractor I noticed that all of my radio presets were gone. Don't know what I did, but I am assuming that's when the APPS stored values were lost.

Any way, not wanting to try a bunch of things at the same time (so I could narrow down the problem), I swapped over from my Auxiliary tank to the main tank. Problem solved. I assumed that the pickup screen in the aux tank must be clogged, so I pulled the pickup/sender assembly from the tank. Imagine my surprise to find NO pickup screen - just two tubes going to the bottom, supporting the float and sender assembly. I fished around in the tank but didn't find anything detached. My next mission was to trace out the line all the way to the tank changeover valve. I found an in-line filter there. I guess it will need to be replaced. I eyeballed a replacement, but I didn't get a chance to change it out today. I'll keep y'all posted.

I verified the problem was gone by doing some hauling. On Thursday I had to go and pick up the last of our hay for the year. I had ten very tightly rolled 5-1/2'X6' bales (avg. 1,100lbs) on the 24' dovetail. Just south of our place on the hill I was WOT and holding 55 m.p.h in fifth. No cutting out or other fueling issues.