APPS/TPS/Speedometer problems. Help Needed.

[GComisky]

I currently a 2003 3500 6spd that has DTC code P2121 and or P2127 coming up with the intermittent throttle response, seems to get damatically worse when temperatures below 25F. Have checked ECM connectors, changed TPS and no fix.



Other problem is with the speedometer jumping radically at times. Checked rear axle sensor and connector and connectors on antilock unit, see nothing wrong.



Any help would be great?

 

[TCDiesel]

Auto or Manual.

 

[barbwire]

Auto or Manual.

Did they even have a 6 sp auto in these trucks in 2003?

 

[TCDiesel]

Did they even have a 6 sp auto in these trucks in 2003?

I always look at the signature,No 6sp Auto in 03, slip my mind it was in his Post , Thanks for the correction.

 

[rbattelle]

Where is your APPS located?

Ryan

 

[GComisky]

This is a 6 spd manual with a bellcrank assy (TPS) mounted under the left hand battery box. Sorry for the confusion.

 

[rbattelle]

Okay, there is a lengthy procedure for diagnosing P2127. Among the things to check:

Check resistance in the wiring harness between the sensor and the ECM. Should be less than 10 ohms on both the supply (disconnect the batteries first!) and the signal lines. If not, harness is bad.

Check resistance between the sensor signal pin and battery negative. Should be >100k ohm.

The manual suggests there are only 2 possibilities for these codes: bad harness or bad ECM.

The fact that the speedometer is also not acting right suggests to me there's an ECM problem.

Ryan

 

[DE Jeeper]

Where is your APPS located?



Ryan

The apps on an '03 is on the front of the head above the cp3. Mine failed at 110k, but you get a throttle responce condition when these go. Most get a dead spot, but mine was serging the engine to red line and not returning to idle.



Aaron

 

[rbattelle]

The apps on an '03 is on the front of the head above the cp3.

That's not always true. Early build 2003s have it located on the intake manifold. Later build (after November 2002) are located beneath the driver side battery.

The manifold-mount are potentiometers, whereas the under-battery units are hall effect sensors.

The diagnostics for each are different, that's why I asked where it was on his truck.

Ryan

 

[Cliffman]

04 auto: I'm having a problem with "dead petal" happening on and off. Bearly made it home. Scanner reads "Throttle Position Sensor". Should I just replace the APPS or could it be something else???



Thanks

Cliff Scott

 

[rbattelle]

Cliff, I'd say if you're experiencing a dead pedal and the APPS is throwing a trouble code, then replace the APPS. Before I did it, however, I'd probably take a few minutes to check the supply voltage (5v) and the ground to the existing APPS.

Ryan