hey guys, having trouble with my 2005 2500 dodge cummins, when i put my foot into her or pulling trailers uphill it seems to kick down the rpm and engine light comes on with p2121, tps which i have changed but hasnt helped with the problem, took it to my mech who tested it and the harness and every thing tests fine, he is guessing its my ecm but thats only his guess without changing it witch dodge quoted me nearly 3k for and says it cannot be returned, anybody have similar problems or any insight would be hugly appreciated, thanks

 

Sounds like your APPS (Accelerator Pedal Position Sensor) needs to be replaced. Good luck cause this is expensive part from the dealership.

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I found this on another site and thought it might help ya test the APPS. Good Luck. Also, search the internet for the part. I have seen the price for the part anywhere from 300-800 bucks.


DRIVABILITY - DIESEL
Symptom:
P2121-APP VOLTS DO NOT AGREE WITH IDLE VALIDATION SIGNAL
When Monitored and Set Condition:
P2121-APP VOLTS DO NOT AGREE WITH IDLE VALIDATION SIGNAL
When Monitored: While the engine is running.
Set Condition: IVS indicates idle whileAPPS signal voltage indicates not at idle condition
or IVS indicates not at idle while APPS signal voltage indicates idle condition. Or, the ECM
detected a conformance error between PPS 1 and PPS 2.
POSSIBLE CAUSES
DAMAGED WIRING HARNESS OR CONNECTOR
FAILED APPS
RATIOMETRIC CIRCUIT SHORTED TO NOT IDLE CIRCUIT
SUPPLY SHORTED TO 12 VOLTS
FAILED ECM
OTHER DTC’s
FAILED PPS
TEST ACTION APPLICABILITY
1 The diesel engine uses two types of throttle position sensors, depending on transmission
configuration and build date.
ENGINE- 5.9L
DIESEL
If the throttle position sensor is located on the engine
Go To 2
If the throttle position sensor is located under the battery on the driver side
of the vehicle
Go To 11
2 Using the DRBIIIt, check for any additional accelerator sensor fault codes.
Do you have any additional accelerator sensor fault codes?
ENGINE- 5.9L
DIESEL
Yes ! Troubleshoot other DTC’s first
Go To 3
No ! Go To 3
3 Verify that the APPS is connected.
Inspect the harness and the APPS connector.
Are any pins damaged?
ENGINE- 5.9L
DIESEL
Yes ! Repair or replace harness or sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 4
P2121-APP VOLTS DO NOT AGREE WITH IDLE VALIDATION SIGNAL —
Continued
ST ACTION APPLICABILITY
4 Measure the resistance between the ratiometric pin of the sensor and the not idle pin
of the sensor.
Is the resistance less than 10 ohms?
ENGINE- 5.9L
DIESEL
Yes ! Replace the sensor
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 5
5 Disconnect the ECM connector.
Inspect the connector for damage.
Are any pins damaged?
ENGINE- 5.9L
DIESEL
Yes ! Fix or replace the harness or the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1.
No ! Go To 6
6 Disconnect the ECM connector and the sensor connector.
Measure the voltage between the supply pin of the sensor connector and battery
negative.
Is the voltage greater than 1 volt?
ENGINE- 5.9L
DIESEL
Yes ! Fix or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 7
7 Measure the resistance between the ratiometric pin of the sensor connector and not
idle pin of the sensor connector.
Is the resistance less than 10 ohms?
ENGINE- 5.9L
DIESEL
Yes ! Fix or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 8
8 Connect the ECM connector.
Measure the resistance between the ratiometric pin of the sensor connector and not
idle pin of the sensor connector.
Is the resistance less than 10 ohms?
ENGINE- 5.9L
DIESEL
Yes ! Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 9
9 Measure the voltage of the supply pin at the sensor connector and battery negative.
Is the voltage greater than 5.5 volts?
ENGINE- 5.9L
DIESEL
Yes ! Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 10
P2121-APP VOLTS DO NOT AGREE WITH IDLE VALIDATION SIGNAL —
Continued
TEST ACTION APPLICABILITY
10 Using DRBIIIt, clear DTC. ENGINE- 5.9L
DIESEL
Repair complete.
11 Using the DRBIIIt, check for any additional PPS fault codes.
Do you have any additional PPS faults?
ENGINE- 5.9L
DIESEL
Yes ! Troubleshoot other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER 1 (DIESEL).
Go To 12
No ! Go To 12
12 Verify that the PPS is connected.
Inspect the harness and the PPS connector.
Are any pins damaged?
ENGINE- 5.9L
DIESEL
Yes ! Repair or replace harness or sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
No ! Go To 13
13 Connect the sensor connector.
Monitor the PPS 1 and PPS 2 voltage with the DRBIIIt while depressing the throttle
pedal.
Is the voltage transition shown on the DRB smooth while depressing the throttle and
is the voltage from PPS 1 twice as much as the voltage from PPS 2?
ENGINE- 5.9L
DIESEL
Yes ! Repair complete.
No ! Replace the PPS
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL).
212

 

yeah thats what i was first going with and changed my tps or apps with no change at all with my problem, it has me baffled and i sure dont want to change my ecm because of the $ unless it is my only option, problem slowly seems to get worse and worse though