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

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Poor driving performance

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>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) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

G13202590

Courtesy of SUBARU OF AMERICA, INC.

CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR (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 the ECM connector and engine ground.
  Connector and terminal.
  
  (B134) No. 14 - Engine ground:
  
  (B134) No. 42 - Engine 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. Ref. to SPEED CONTROL SYSTEMS (H4DOTC)>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) (H4DOTC)>ENGINE CONTROL MODULE (ECM) .