DTC P0122: Throttle/Pedal Position Sensor/Switch "A" Circuit Low: Notes

WARNING: This page is about a different variant/trim than selected.

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DTC detecting condition:

Immediately at fault recognition

Trouble symptom:
- Improper idling
- Engine stall
- Poor driving performance
Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM (IMPREZA MODEL)>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .
- IMPREZA MODEL
Courtesy of SUBARU OF AMERICA, INC.
- CROSSTREK MODEL
Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL (SHORT TO GROUND) .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connectors from electronic throttle control.
4. Measure the resistance between ECM connector and chassis ground.
  Connector and terminal
  
  (E158) No. 27 - Chassis ground:
  
  (E158) No. 29 - Chassis ground:
  
  (E158) No. 29 - (E158) No. 44:
  
  Is the resistance 1 MΩ or more?
  
  Yes: Go to 2.
  
  No: Repair the ground short circuit of harness between ECM connector and electronic throttle control connector.
CHECK ECM (INTERNAL SHORT) .
1. Connect the connector to ECM.
2. Measure the resistance between electronic throttle control connector and engine ground.
  Connector and terminal
  
  (E57) No. 6 - Engine ground:
  
  Is the resistance 1 MΩ or more?
  
  Yes: Replace the electronic throttle control. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>THROTTLE BODY .
  
  No: Repair the ground short circuit of harness between ECM connector and electronic throttle control connector. Replace the ECM if defective. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>ENGINE CONTROL MODULE (ECM) .