P2123
DTC P2122, P2123, P2127, P2128, or P2138
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions 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
Typical Scan Tool Data
Circuit/System Description
The accelerator pedal assembly contains 2 accelerator pedal position (APP) sensors. The APP sensors are mounted to the accelerator pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to 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 APP sensors 1 and 2 signal percentages increase as the pedal is depressed, from approximately 0% at rest to above 95% when fully depressed.
The ECM provides the accelerator pedal position or driver torque request to the hybrid powertrain control module. The hybrid powertrain control module determines how the torque output will be distributed between the two electric motors and the engine.
Conditions for Running the DTC
P2122, P2123, P2127, P2128
* DTC P0697 is not set - P2127 or P2128.
* DTC P06A3 is not set - P2122 or P2123.
* The ignition is ON or the engine is running
* The run/crank voltage is greater than 6.4 V.
* 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 the engine is running
* The run/crank voltage is greater than 6.4 V.
* 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 greater than 1 s.
P2123
The ECM detects that the APP sensor 1 voltage is greater than 4.7 V for greater than 1 s.
P2127
The ECM detects that the APP sensor 2 voltage is less than 0.32 V for greater than 1 s.
P2128
The ECM detects that APP sensor 2 voltage is greater than 2.6 V for greater than 0.5 s.
P2138
The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for greater than 1 s.
Action Taken When the DTC Sets
* DTCs P2122, P2123, P2127, and P2128, and P2138 are Type A DTCs.
* A message center displays Propulsion Power is Reduced.
Conditions for Clearing the DTC
DTCs P2122, P2123, P2127, and P2128, and P2138 are Type A DTCs.
Diagnostic Aids
* A high resistance condition on the accelerator pedal sensor 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 [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
Hybrid Modes of Operation Description Hybrid Modes of Operation Description
Throttle Actuator Control (TAC) System Description Throttle Actuator Control (TAC) System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
1. Vehicle in Service Mode.
2. Verify DTC P0697 or P06A3 is not set.
• If any of the DTCs are set
Refer to for DTC P0641, P0651, P0697, or P06A3 (ECM) Powertrain Management (ECM) further diagnosis.
• If none of the DTCs are set
3. Verify the APP Sensor 1 Circuit Status and APP Sensor 2 Circuit Status displays OK.
• If Malfunction is displayed
Refer to Circuit/System Testing
• If OK is displayed
4. Verify the scan tool APP Sensor 1 and 2 Agree/Disagree parameter displays Agree while performing the tests listed below:
* 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.
• If Disagree
Refer to Circuit/System Testing
• If Agree
5. Verify that DTC P2122, P2123, P2127, P2128, or P2138 is not set.
• If any of the DTCs are set
Refer to Circuit/System Testing
• If none of the DTCs set
6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
7. Verify DTC P2122, P2123, P2127, P2128, or P2138 is not set.
• If any DTC sets
Refer to Circuit/System Testing
• If no DTCs set
8. All OK
Circuit/System Testing
1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the B107 accelerator pedal assembly. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohm between each low reference circuit terminal listed below and ground.
* Low reference circuit terminal 4 or A
* Low reference circuit terminal 5 or D
• If 5 ohm or greater
1. Vehicle OFF, disconnect the harness connector at the K20 engine control module.
2. Test for less than 2 ohm in the low reference circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K20 engine control module.
• If less than 5 ohm
3. Vehicle in Service Mode.
4. Test for 4.8-5.2 V between each 5 V reference circuit terminal listed below and ground.
* 5 V reference circuit terminal 1 or C
* 5 V reference circuit terminal 2 or F
• If less than 4.8 V
1. Vehicle OFF, disconnect the harness connector at the K20 engine control module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohm in the 5 V reference circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K20 engine control module.
• If greater than 5.2 V
1. Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode.
2. Test for less than 1 V between the 5 V reference circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 engine control module.
• If between 4.8-5.2 V
5. Verify each APP sensor voltage parameter is less than 0.2 V.
• If 0.2 V or greater
1. Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode.
2. Test for less than 1 V between the signal circuit terminal listed below and ground.
* APP sensor 1 signal circuit terminal 3 or E
* APP sensor 2 signal circuit terminal 6 or B
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 engine control module.
• If less than 0.2 V
6. Install a 3 A fused jumper wire between each signal circuit terminal listed below and the 5 V reference circuit terminal 1.
* APP sensor 1 signal circuit terminal 3 or E
* APP sensor 2 signal circuit terminal 6 or B
7. Verify the scan tool APP sensor voltage parameter is greater than 4.8 V.
• If 4.8 V or less
1. Vehicle OFF, disconnect the harness connector at the K20 engine control module.
2. Test for infinite resistance between the signal circuit terminal and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohm in the signal circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, replace the K20 engine control module.
• If greater than 4.8 V
8. Test or replace the B107 accelerator pedal assembly.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Accelerator Pedal Position Sensor Replacement Service and Repair
* Control Module References Programming and Relearning for ECM replacement, programming, and setup