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DTC P2122, P2123, P2127, P2128, or P2138 (With Turbocharger)

DTC P2122, P2123, P2127, P2128, or P2138 (With Turbocharger)

Diagnostic Instructions


Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptors

DTC P2122

Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage

DTC P2123

Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage

DTC P2127

Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage

DTC P2128

Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage

DTC P2138

Accelerator Pedal Position (APP) Sensors 1-2 Not Plausible

Diagnostic Fault Information

Circuit Short to Ground High resistance Open Short to Voltage Signal Performance
Accelerator Pedal Position (APP) Sensor 1 5 V Reference Circuit

P06A3

P2138

P2122

P06A3

P2138

Accelerator Pedal Position (APP) Sensor 2 5 V Reference Circuit

P0108, P0107, P0697

P2138

P2127

P0106, P0108, P0697

P2138

Accelerator Pedal Position (APP) Sensor 1 Signal

P2122

P2138

P2122

P2123, P2138

P2138

Accelerator Pedal Position (APP) Sensor 2 Signal

P2127

P2138

P2127

P2128,P2138

P2138

Accelerator Pedal Position (APP) Sensor 1 Low Reference

-

P2138

P2123

-

P2138

Accelerator Pedal Position (APP) Sensor 2 Low Reference

-

P2138

P2128

-

P2138



Typical Scan Tool Data

APP Sensor 1

Circuit Short to Ground Open Short to Voltage
Operating Conditions: The engine is operating at idle.

Parameter Normal Range: APP Sensor 1 0.88-1.08 V

APP Sensor 1 5 V Reference

0.00 V

0.00 V

2-3 V

APP Sensor 1 Signal

0.00 V

0.00 V

4.98 V

APP Sensor 1 Low Reference

-

4.94 V

-



APP Sensor 2

Circuit Short to Ground Open Short to Voltage
Operating Conditions: The engine is operating at idle.

Parameter Normal Range: APP Sensor 2 0.39-0.59 V

APP Sensor 2 5 V Reference

0.00 V

0.00 V

1.35 V

APP Sensor 2 Signal

0.00 V

0.00 V

2-5 V

APP Sensor 2 Low Reference

-

4.92 V

-



Circuit/System Description

The accelerator pedal assembly contains 2 accelerator pedal position (APP) sensors. The APP sensors are mounted on the accelerator pedal assembly and are not serviceable. The APP sensors send a signal voltage that changes relative to the pedal position. The engine control module (ECM) supplies each APP sensor with a 5 V reference circuit, a low reference circuit, and a signal circuit.

Both the percentages for APP sensor signals 1 and 2 increase when the pedal is pressed. From about 0 percent in rest position to over 95 percent fully pressed.

Conditions for Running the DTC


P2122, P2123, P2127, or P2128

DTC P06A3 or P0697 are not set.

The ignition is ON or engine is running.

The ignition voltage is greater than 6 V.

The ECM is not commanding reduced power.

The DTCs run continuously when the above conditions are met.



P2138

DTCs P06A3, P0697, P2122, P2123, P2127, or P2128 are not set.

The ignition is ON or engine is running.

The ignition voltage is greater than 6 V.

The ECM is not commanding reduced power.

The DTC runs continuously when the above conditions are met.


Conditions for Setting the DTC

P2122

The ECM detects that the APP sensor 1 voltage is less than 0.46 V for less than 1 s.

P2123

The ECM detects that the APP sensor 1 voltage is greater than 4.7 V for less than 1 s.

P2127

The ECM detects that the APP sensor 2 voltage is less than 0.32 V for less than 1 s.

P2128

The ECM detects that the APP sensor 2 voltage is greater than 2.6 V for less than 1 s.

P2138

The ECM detects that APP sensor 1 and APP sensor 2 disagree greater than 10 percent for less than 1 s.

OR

The ECM detects that both APP sensor 1 and APP sensor 2 are 5 percent greater than the learned minimum position for less than 1 s.

Action Taken When the DTC Sets


DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.

The ECM commands the TAC system to operate in a reduced engine power mode.


Conditions for Clearing the DTC

DTCs P2122, P2123, P2127, P2128, and P2138 are type A DTCs.

Diagnostic Aids


A high resistance condition on the accelerator pedal position circuits could cause a DTC to set.

Ensure that the in-line harness connector seals are installed correctly. Improper installation could result in water intrusion into the connector and cause a DTC to set.


Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Throttle Actuator Control (TAC) System Description

Electrical Information Reference


Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification


1. Ignition ON, observe the DTC information with a scan tool. Verify DTCs P0697 or P06A3 are not set.

2. If the DTC is set, refer to DTC P0641, P0651, P0697, or P06A3 (ECM) for further diagnosis.

3. Ignition ON, observe the scan tool Accelerator Pedal Position percentage parameter. The scan tool should display 0 percent.

4. Observe the scan tool APP Sensor 1 and 2 Agree/Disagree parameter while performing the following tests:

Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times.

Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.

The APP Sensor 1 and 2 Agree/Disagree parameter should display Agree.

5. Use a scan tool to read the DTC Info. DTC P2122, P2123, P2127, P2128, or P2138 should not be set.

6. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the B107 accelerator pedal assembly.

2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the low reference circuit terminals listed below and ground.

Low reference circuit terminal 4 or A

Low reference circuit terminal 5 or D

3. If greater than the specified range, disconnect the ECM and test the appropriate low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

4. Ignition ON, test for 4.8-5.2 V between both 5 V reference circuit terminals listed below and ground.

5 V reference circuit terminal 1 or C

5 V reference circuit terminal 2 or F

5. If less than the specified range, test the appropriate 5 V reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K20 ECM.

6. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

7. Verify the appropriate APP sensor voltage parameter is at 0 V.

8. If greater than the specified range, disconnect the ECM and test the appropriate signal circuit terminal listed below for a short to voltage. If the circuit tests normal, replace the K20 ECM.

APP sensor 1 signal circuit terminal 3 or E

APP sensor 2 signal circuit terminal 6 or B

9. Install a 3 A fused jumper wire between the appropriate signal circuit listed below and the 5 V reference circuit terminal 1. Verify the appropriate APP sensor voltage parameter is greater than 4.8 V.

APP sensor 1 signal circuit terminal 3 or E

APP sensor 2 signal circuit terminal 6 or B

10. If less than the specified range, test the appropriate signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

11. If all circuits test normal, replace the B107 accelerator pedal assembly.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.


Accelerator Pedal Position Sensor Replacement

Control Module References for ECM replacement, programming and setup