DTC P2127: Throttle/Pedal Position Sensor/Switch "E" Circuit Low: Notes

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

1. -

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
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

G13614915

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 ACCELERATOR PEDAL POSITION SENSOR (SHORT TO GROUND) .
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 and terminal
  
  (B134) No. 52 - Chassis ground:
  
  (B134) No. 64 - Chassis ground:
  
  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.
CHECK SHORT CIRCUIT INSIDE ECM (SHORT TO GROUND) .
1. Connect the connector to ECM.
2. Measure the resistance between accelerator pedal position sensor connector and chassis ground.
  Connector and terminal
  
  (B315) No. 3 - Chassis ground:
  
  Is the resistance 1 MΩ or more?
  
  Yes: Replace the accelerator pedal assembly. Ref. to SPEED CONTROL SYSTEMS (H4DO (EXCEPT FOR HEV))>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 (EXCEPT FOR HEV))>ENGINE CONTROL MODULE (ECM) .