Same problem, newer truck

[modracr41]

Hey guys, I need some help. I recently bought a 99 D3500 with the cummins and 5-speed manual tranny. A couple of months ago, I was on my way to Oklahoma, with the cruise set and all of a sudden, the engine defaulted to idle, and the check engine light came on. I tried to manually accelerate with the pedal, and when I pushed it to the floor and let go, it would reset and start working again. This had happened more and more, and it happens now without the cruise. It will default to idle, and you push the pedal to the floor, and let it all the way back up, then when you get back into the throttle, it works fine. Could this be a bad tps or a bad acc. pedal position sensor? Any help would be greatly appreciated. Thanks, and ....................See ya at the track!!

[brian sauser]

I work at a dodge dealership and work on the diesel's alot. I know that when you install a new TPS you have to run the throttle from idle to WOT so the Engine Control Module can learn the new TPS. It sounds like the ECM is losing the TPS signal for a split second either at the ECM or the TPS and thats why when you run the throttle to the floor the ECM relearns the TPS again and you have throttle control. Even though the TPS wasn't changed, this will happen even if the TPS is unplugged and plugged in with the key on. I would check the connector at the TPS for spread terminals and the wiring from the TPS to the ECM for damage, if they are I would say the problem might be in your TPS.

[maumau]

Looks as if the others are answering you and I agree with what they are saying....wiring / and or sensor...could be a computer also.. one thing to add...problem should be setting a "fault" code..if not get hold of a diag. manual and look problem with no check engine lamp lit...

[modracr41]

Thanks guys. I suspected as much. I'm a senior technician/End of line trainer for GM and had a suspicion that this was the problem. The problem is, I don't have a DRB. I have a Tech II, so I have no way, other than the obvious, to check the codes. After 5 key cycles, the codes go into the history, and the check engine light goes out until the next failure.
I'll check the wiring at the TPS and run the wires to see. Thanks again for the confirmation, and ...................See ya at the track!!

[J-BODY]

[QUOTE]Originally posted by brian sauser
. I know that when you install a new TPS you have to run the throttle from idle to WOT so the Engine Control Module can learn the new TPS. [/QUOTE
??? Any chance this statement is in writing somewhere?

[brian sauser]

The only place I have that in writing is in the dodge service manual, in the fuel section. The TPS, or as on the diesel Accelerator Pedal Position Sensor, APPS, needs to be calibrated to the ECM by slowly pressing throttle pedal to floor and then slowly release. I don't know if this will help you, I was told this at Chrysler diesel training by the instructor and read in the service manual. If APPS is not calibrated, ECM thinks that voltage is the voltage at idle, and will until it's calibrated. I don't know of any other book that this is in, but i have not looked elsewhere.