DTC P2122: Throttle/Pedal Position Sensor/Switch "D" Circuit Low: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Poor driving performance

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Clear Memory Mode>OPERATION , and inspection mode Ref. to ENGINE (DIAGNOSTICS) (H4DO)>Inspection Mode>PROCEDURE .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM

G12409941

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connector from the accelerator pedal position sensor.
4. Measure the resistance between ECM connector and chassis ground.
  Connector & terminal
  
  (B134) No. 30 - Chassis ground:
  
  (B134) No. 29 - Chassis ground:
  
  (B134) No. 29 - (B134) No. 53:
Is the resistance 1 MΩ or more?

Yes: Go to 2

No: Repair the short circuit to ground in harness between ECM connector and accelerator pedal position sensor connector.

NOTE: In this case, repair the following item:
- Short circuit of harness between ECM connector and engine ground
- Poor contact of ECM connector
- Poor contact of coupling connector
CHECK SHORT CIRCUIT INSIDE THE ECM.
1. Connect the connector to ECM.
2. Measure the resistance between accelerator pedal position sensor connector and chassis ground.
  Connector & terminal
  
  (B315) No. 6 - Chassis ground:
Is the resistance 1 MΩ or more?

Yes: Replace the accelerator pedal. Ref. to SPEED CONTROL SYSTEMS(H4DO)>ACCELERATOR PEDAL

No: Repair the short circuit to ground in harness between ECM connector and accelerator pedal position sensor connector. Replace the ECM if defective. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM)