DTC P2123: Throttle/Pedal Position Sensor/Switch "D" Circuit High: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Improper idling
• Poor driving performance

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC P06B1 displayed? (Current code)

   Yes:  Check for DTC P06B1. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P06B1 SENSOR POWER SUPPLY "A" CIRCUIT LOW .

   No:  Go to  2.

2. CHECK DTC  .

   Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC P06B2 displayed? (Current code)

   Yes:  Check for DTC P06B2. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P06B2 SENSOR POWER SUPPLY "A" CIRCUIT HIGH .

   No:  Go to  3.

3. CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR (OPEN)  .
   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 of harness between ECM connector and accelerator pedal position sensor connector.

      Connector & terminal 

      (B61) No. 19 - (B93) No. 5:

      (B61) No. 35 - (B93) No. 6:

   Is the resistance less than 1 Ω?

   Yes:  Go to  4.

   No:  Repair the open circuit of harness between ECM connector and accelerator pedal position sensor connector.

4. CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR (OPEN)  .
   1. Connect the connector to ECM.
   2. Measure the resistance between accelerator pedal position sensor connector and chassis ground.

      Connector & terminal 

      (B93) No. 5 - Chassis ground:

   Is the resistance less than 5 Ω?

   Yes:  Go to  5.

   No:  Repair the following item.

   • Open circuit in harness between ECM connector and Chassis ground
   • Poor contact of ECM connector
5. CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR (SHORT TO POWER SUPPLY)  .
   1. Turn the ignition switch to ON.
   2. Measure the voltage between accelerator pedal position sensor connector and chassis ground.

      Connector & terminal 

      (B93) No. 6 (+) - Chassis ground (-):

   Is the voltage 5 V or more?

   Yes:  Repair the short circuit to power supply in harness between ECM connector and accelerator pedal position sensor connector.

   No:  Go to  6.

6. CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR CONNECTOR (LINE-TO-LINE SHORT)  .

1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance between ECM connectors.

   Connector & terminal 

   (B61) No. 51 - (B61) No. 35:

Is the resistance 1 MΩ or more?

Yes:  Repair the poor contact of accelerator pedal position sensor connector. Replace the accelerator pedal assembly if defective. Ref. to SPEED CONTROL SYSTEMS (H4DOTC)>ACCELERATOR PEDAL .

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