Spark

DTC P2122, P2123, P2127, P2128, or P2138

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 5V 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.

P2122, P2123

P2127, P2128

P2138

P2122

The ECM detects that the APP sensor 1 signal voltage is less than 0.12V.

P2123

The ECM detects that the APP sensor 1 signal voltage is greater than 4.88V.

P2127

The ECM detects that the APP sensor 2 signal voltage is less than 0.12V.

P2128

The ECM detects that the APP sensor 2 signal voltage is greater than 3.0V.

P2138

The ECM detects that the difference between APP 1 and APP 2 is greater than the predetermined values.

DTC P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.

DTC P2122, P2123, P2127, P2128, and P2138 are Type A DTCs.

Schematic Reference

Engine Controls Schematics : Siemens ECM - LPG with LCP → Siemens ECM - Gas without FX3 or LCP → Delphi ECM - FX3

Connector End View Reference

Component Connector End Views

Description and Operation

Throttle Actuator Control (TAC) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. Verify no DTCs are set.

⇒	If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

2. Ignition ON, observe the scan tool APP Sensor 1 and 2 voltage parameters. Verify both of the APP Sensor 1 and APP Sensor 2 voltages parameters are between 0.4-4.5V.
3. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. DTCsP2122, P2123, P2127, P2128, or P2138 should not set.
4. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCsP2122, P2123, P2127, P2128, or P2138 should not set.
5. Observe the APP Sensor 1 and 2 parameter. The APP Sensor 1 and 2 parameter should display Agree.
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.

1. Ignition OFF, disconnect the B107 accelerator pedal position sensor harness connector at the accelerator pedal assembly.
2. Ignition OFF for 1 min, test for less than 5Ω between the B107 accelerator pedal position sensor low reference circuit terminals listed below and ground.

•	Low reference circuit terminal 4

•	Low reference circuit terminal 3

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

Note: The 5V reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.

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

•	5V reference circuit terminal 6

•	5V reference circuit terminal 1

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

⇒	If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 engine control module.

4. Verify the scan tool APP Sensor 1 or APP Sensor 2 voltage parameter is less than 0.1V.

⇒	If greater than the specified range, test the appropriate signal circuit terminal listed below for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

•	APP sensor 1 signal circuit terminal 5

•	APP sensor 2 signal circuit terminal 2

5. Install a 3A fused jumper wire between the appropriate signal circuit terminal and the 5V reference circuit terminal of the B107 accelerator pedal position sensor listed below. Verify the scan tool APP Sensor 1 or APP Sensor 2 voltage parameter is greater than 4.8V.

•	APP sensor 1 signal circuit terminal 5 and 5V reference circuit terminal 6

•	APP sensor 2 signal circuit terminal 2 and 5V reference circuit terminal 1

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

6. If all circuits test normal, replace the B107 accelerator pedal position sensor.

Perform the Diagnostic Repair Verification Diagnostic Repair Verification after completing the diagnostic procedure.