Coaldigger

I've done some searching through the forums and checked the FAQs but still can't seem to find a clear answer....

2001 Dodge RAM 2500 Quad Cab SLT 6 speed HO w/ cruise control. 139,000 miles or so.

I take it for it's longest trip since I've owned it (a little over a year) about a 370 mile round trip. In the last 40 miles I notice when I pull up to a light it's idling at 1300 or 1400 RPM. I drive another 20 miles with the cruise on and pull off onto an onramp and the accelerator does nothing, the truck just idles. I idle it off the road in 2nd gear and notice there's an engine code. I shut it down, fire it back up and accelerator works fine. Take it another 10 miles and it goes to idling again. I idled it off the road, shut it down, waited about 30 seconds, fire it back up, and it works fine again.

The two codes were

P0121 - Throttle Position Sensor (TPS)/ Accelerator Pedal Position Sensor (APPS) circuit Voltage range problem

P0122 - Throttle Position Sensor (TPS)/ Accelerator Pedal Position Sensor (APPS) signal voltage too low.

Now firstly, which is defective, the TPS or the APPS (or are they the same thing). Secondly, where is it at, at the accelerator pedal or on the injection pump?

Mine has no cable or at least I don't think it does. The Cruise control does not actuate the pedal in the cab when it's set....

Any help is greatly appreciated!!!

Coal Digger

Tate

APPS is the unit that bolts to the head at the front, has 3 10mm bolts, aluminum bracket and big black plastic cover. Your crusie is electronic, which is why the pedal springs back when you engage it.

Coaldigger

Thanks for the info.

Second question... Is the APPS the same as the TPS? I have found several places that sell a TPS from $342 to $419. Is this what I'm needing?

If it is, I've found a few brands, which would you recommend...

Napa (unknown brand)

Advanced Auto (Which I've had alot of problems with their electrical components like alternators and starters.)

Niehoff - 3 month warranty

BWD Automotive 1 year warranty


Rockauto.com
Standard Motor Company



I've heard about Cummins having them, but who would I contact with Cummins to get one?

Thanks yall!

Coal Digger

Tate

When I bought mine, it was Dealer only, Cummins didn't stock them. That being said, every place is different. Call your closest Cummins store, and talk to parts. Give them your engine serial number and they can probably look it up.

TPS is usually referred to the 12v engines for auto tranny stuff. APPS is the 24v version, which is the throttle by wire sensor, plus it acts as the TPS if there is an auto.

My APPS was $500 from the dealer, so the ones you priced out might be it. Get one to order it in and then see if it looks the same as yours. If it does, great, if not, continue looking.

nickg

Do a search for Timbo01, he has a replacement (more robust) for 160$ at least you have codes and know its a failed APPS

here are a couple of links to show what your looking for
Some pics and explanation of how it works
http://www.cumminsforum.com/forum/98...ps-sequel.html

http://www.cumminsforum.com/forum/98...pp-sensor.html

This link has the contact info for Tim
http://mopar.mopar1973man.com/tips/c...eplacement.htm

Coaldigger

Thanks yall and Merry Christmas!!!!

Coaldigger

Just and update. The TPS sensors they offer at Napa and Advance Auto are the same as the APPS. I purchased mine from Napa for under $400 and put it in. No problems so far.

Happy New Year,
Coal Digger

Coaldigger

Well, the APPS is at it again. The new Napa one I installed back in the winter was identical (even the barcode sticker on the sensor) to the one in the truck. So much that I cleaned up the old one and took it back to my friend at Napa and told him he gave me the wrong part. He looked at it and was about to give me a refund But I'm to honest I guess so I let him know what was going on. I did the reset also using the ignition key.


I was going on a 1 hour trip and used the cruise set at 60mph. When I had to pull up to a light my truck was high idling at about 1200 to 1300 RPM. I went to the next light and had dead pedal with a P0121 code. I shut the ignition off and fired it back up and it worked again. I had also been noticing some surging when doing a steady speed using just the pedal and not the cruise. It has gotten worse. It doesn't surge with the cruise set which leads me to believe the potentiometer in the APPS is varying the voltage a little.

Anytime I use the cruise it ends up high idling and throws an APPS code until I cycle the engine. It doesn't dead pedal all the time, but it's very annoying and I know the surging is not good for the engine when I'm using the pedal.

Come to think of it, when I had the problem with the first APPS it was the first time I used cruise for a long trip.

Any ideas? I've already got a warranty replacement APPS and am going to put it in right now.

Anyone think the cruise module is causing a problem or am I just getting a hold of cheap Made in Mexico APPS sensors that don't like the cruise circuitry.

Any help is greatly appreciated!

Coal Digger

nickg

the Timbo APPS is a better unit than the oem one, so far I've not seen any reports of the Timbo unit failing, That being said my orginal has 430,000kms on it but when it goes I'll be replacing it with timbos version. I instaled one of timbo's on an 03 truck, it was simple to instal and required no adjustment as it was within spec's once it was bolted on, I changed it for a friend in a grocery store parking lot, his truck only had 200,000kms on it and locally a new one was almost 800$ at the dealer!

SWC

Coaldigger, nickg gave good advice Timbo APPS. I have around 440,000 km on my 01.5 and mine has been replaced twice. First one under warranty and the second one about a month before the Timbo unit was available. My symptoms were identical to yours.
I see your replacement is no cost to you. If you can get a freeby go with it. As long as NAPA will replace it for nothing you just get to know how to replace it more quickly. (Keep hoping that these replacements don't fail entirely when you can't get a replacement easily!)
Stan

Coaldigger

Thanks for the advice. If I was unable to go with the warranty I was planning on the Timbo version. When I took the new faulty one off I felt a bit of "grit" when I was rotating it. It definately failed.

I was noticing that the APPS has a few places on the linkage for additional springs, however the bracket itself didn't seem to have any holes in it for springs. I wondered if the rotational spring was also supposed to be supplemented with another to stiffen up the pedal. If you're on rough roads, the weight of your leg bouncing is enough to keep goosing the throttle which adds a lot of extra movement inside the APPS within a small portion of the potentiometer. I added a few extra springs to help with this and hope it adds to the lifespan of the new one.

Thanks again for your help!

Coaldigger

mwm

mine is doing the same thing ...any help... what did you do to fix yours? or did you sell it?
thanks mwm

AlpineRAM

same codes?

what year/model truck?

mwm

my truck is a 2001 2500 5.9HO 6 speed 2wd

AlpineRAM

Got any codes?

2001 should work with the key trick- turn ignition key from off to run 3 times, watch odometer.