Engine/Transmission (1998.5 - 2002) Tell me about the TPS

[telliott]

Got a Low TPS voltage code. Cant rememeber the exact number p0106 or something like that.



What does this mean? should i replace the sensor?



Maybe this is a dumb quesiton, but i dont even know where the sensor is or what it looks like. Is it easily replaced? Cost? Where can i get one?



Everything seems to be running ok as of now.

 

[JLandry]

telliot,



There are a few common APPS related trouble codes that can pop up. Maybe it was one of these:



P0121-ACCEL POS SENSOR VOLTS DO NOT AGREE W/IDLE VALID SIGNAL

P0122-APP SENSOR SIGNAL VOLTAGE

P0222-IDLE VALIDATION SIGNALS BOTH LOW

P0223-IDLE VALIDATION SIGNALS BOTH HIGH



In any case, assuming you don't have a wiring problem (unlikely but possible), then you have three options to replace the APPS:



Option 1 (worst choice): Buy an OEM replacement assembly from a Dodge or Cummins dealer (online or local), or an auto parts store for over $350 each. This OEM unit consists of a large cast aluminum bracket, a bell crank assembly, and a TPS (Throttle Position Sensor). Interestingly, it's just the TPS that fails and is the only thing needing replacement, but Dodge or Cummins doesn't sell the just TPS alone.



Option 2 (a better choice): Buy just a TPS from Williams Controls, the manufacturer of these devices, and install it in place of the original TPS located on the APPS assembly. This can be done for about $125. But to do this you need to fabricate a wiring harness adapter to go between the new Williams Control TPS and the Dodge wiring harness. It's not difficult, but you do at least have to know how to solder. Full details can be found in this post:



DIY APPS Instructions



Option 3 (the best): Buy just the TPS with a pre-made wiring harness adapter from one of the following sources:



Blue Chip Diesel Performance - $175



Forum member Timbo - Not sure of current price, but probably around $125-150. Send him a PM or email to inquire.



The APPS is located on the front of the engine on the driver's side. Look for the black accelerator cable coming from firewall and follow it toward the front of the engine where you'll see it go into the APPS assembly. The TPS is hidden from view on the side of the APPS until you unbolt it from the engine. Removing the APPS assembly is a piece-of-cake: First remove the black plastic cover, pop off the accelerator cable and transmission kick-down cable from the bell crank assembly, remove the 4 bolts (going from memory) holding it to the engine, unplug the wiring harness and it's off. The TPS is fastened to the side of the cast aluminum APPS bracket by two screws.



If you buy a replacement TPS from Blue Chip Diesel or Timbo, installation and calibration instructions are included.



Good luck,



John L.

 

[GaryOwen]

Option 1 above from Chrysler is now over $500. Option 3 - I bought one from Timbo and it worked perfectly on my 03. Last price that I heard was $160.

 

[turbo torque]

I bought one from Timbo a couple weeks ago and, all is great.

 

[telliott]

i will have to pull codes again to see if it threw the code again and see exactly which one it was. Is this something that i should replace immediatly? As i said before, i havent noticed anything different in the way its running. throttle response seems normal.

 

[JLandry]

If your truck is otherwise operating fine, then no... there's no particular rush. Rarely does an APPS fail suddenly leaving you stranded. Typically you'll start by getting engine rpm control problems, trouble codes, and auto transmission shifting problems that gradually get worse as the APPS fails.



Regards,



John L.

 

[jeepit]

Mine ran for 4 months after it threw a code till I finally got a dead pedal. Then ordered from Timbo and it's working fine again...

 

[telliott]

ok, thanks for all the help. I appreciate it.

 

[Bob Cochran]

With mine besides codes I got dead pedal let off go pedal then it came back to running right. It seems to happen at just one RPM for me but not every time though. Good luck with it.

 

[hcole]

Mine started surging about 3 weeks ago and didn't set any codes. I was able to read the posts on here about APPS problems and decided to order Timbo's APPS. Easy to install and set. It worked like a champ. Thanks to all here who basically reengineered a poor DC design. Cost of APPS was $160. 00.

 

[RClark]

Where do I find TIMBO?

 

[hcole]

I think he can be found here. Email at -- email address removed --.

 

[rweis]

I was part of the "crew" to rework the APPS. The "rework" runs fine after I think 2 years or so (not sure how long ago it was). I experimented with using a micro-switch in place of the "electronic circuit" and the micro-switch still runs fine (I had to build an adapter plate to screw the microswitch to).



The Williams Control is a really good fix for the poor Dodge design, simple, effective, good value. Many years later, still running great. Was a good contribution to the TDR body of knowledge.



Bob Weis