Archived Throttle Position Sensor Issue

[nmurray]

I was driving my truck and the check engine light came on and the engine returned to idle. Nothing I did with the throttle pedal increased rpm even in neutral. I limped the truck to the next exit. When I was stopped I also had no throttle response. Shut off engine and cycled key to get codes:



P PCU P0500 and P1693

P ECU P0121, P1693, and P0602



I restarted the truck and the throttle worked again. I had over 300 miles to home so I went 5 miles to the local Cummins distributor. They do not have a replacement sensor in stock and say that the sensor can not be ordered individually. I told them Genos sells them for $170. They want to replace the whole housing. The parts price is $450. None of their locations have the housing. Anyone in the Columbus, OH or on the way to Pittsburg, PA that has a sensor for a 2002 24V? I am not sure how long it will last or when it will die.

 

[Joe Mc]

Best bet is to order the part from Genos, go for the ride home - fingers crossed - and change it out when you get home. Otherwise you'll be out the $450 + install by Cummins. If it dead pedals on the ride home at least you'll be closer and someone can pull you in.

Good luck to you man.

 

[JLandry]

nmurray,

With that group of trouble codes, I wouldn't be so sure you have an APPS problem. If you haven't already looked them up, here are the definitions:

P-0121 ACCEL POS SENSOR VOLTS DO NOT AGREE W/IDLE VALID SIGNAL (DIESEL)
P-0500 NO VEHICLE SPEED SENSOR SIGNAL
P-0602 ECM FUELING CALIBRATION ERROR

That last one, the P0602, can cause the engine to enter a "limp" mode which would mean engine idle and no throttle response. Restarting the engine could clear the limp mode just as you experienced it. If the APPS was so bad that you completely lost throttle response, it's more likely it wouldn't have disappeared simply by restarting the engine.

Keep in mind the APPS can be tested using a multimeter by following the procedures outlined in the Dodge Diagnostic Manual. While it can't hurt to replace the TPS with one from Geno's, I have a feeling you may find something else is causing this problem. It could instead be a failing ECM or possibly just a corroded or loose wiring harness connector.

I think I'd start by clearing the trouble codes (using an inexpensive code scanner) and then I'd disconnect, inspect, clean, and reconnect the ECM connector. Drive the truck and see which, if any, trouble codes come back and deal with them one by one.

Just curious, have you recently (temporarily) lost your speedometer indication on the instrument panel?

John L.

 

[bromano676]

send TIMBO a pm he is in PA.

 

[nmurray]

I went to Cummins Bridgeway in Columbus OH. They said that it was the APPS issue. I never lost the speedo. I think the speedo code comes from the speedo calibrator that I have installed to correct for my slightly larger tires. The ECM has been reflashed by a retired Cummins engineer. So the ECM has a "special" cal that works with the 275 RV injectors. All that work was done over a year and 40K miles ago. Cummins did say that that Cummins error code 375 was maxed out on counts. I think that the Cummins 375 matches the Dodge P0602 code. They said that this code was for an ECM request of the VP44 for timing or fuel injection rate higher than the VP44 would allow. I am fairly certain that this is due to the "special" cal.



I made it home. Too bad I have a 2010 CC in the driveway that I can't use because the bed is not finished. Can't get much work done with bare frame rails. Also sucks paying $250 to hear what you already know from Cummins. They wanted $450 + $76. 5 to air freight it in for Monday or $450 + $175 to air freight it in for Sat. Rediculous. From what I have read this is a fairly common part to fail and a Cummins distributor does not have it on the shelf. I would have paid the $450 to not roll the dice on the way home.

 

[Joe Mc]

Glad you made it home. No problems on the way?

 

[bromano676]

The one that Geno's, Timbo, Bluechip, etc, sells is better then the dodge part. I changed mine 18 months ago spent 500 for the dodge part, and had to do it again 6 months ago. I put in the TIMBO APPS, so far so good. It was only 160, and from all the research that I've done, It is a MUCH better part.

 

[nmurray]

Yes I made it home no problem. The check engine light never came back on and I had throttle the whole way. I also ordered the TIMBO APPS today.



Thanks for the help.

 

[dknoch]

Glad you made it home! I just went through similar issues with mine but the TPS didn't fix the problem. My problem was the ECM. It wasn't getting an input from the TPS. Cruise control on these 6 speed trucks still works since that is not associated with the TPS. The 0602 code is pretty common with the SMARTY programming so that may be similar to your program. The TPS install was quite easy though so good luck!

Dan Knoch

 

[Bloomy]

Likewise had similar problems and codes. Ended up being the ECM. Did replace the APPS sensor with Timbo's. Unfortunately that wasn't the problem, but left that sensor in place since it is a better unit than the Dodge/Cummins.



Thomas