ENGINE (DIAGNOSTICS)(H4SO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P2123 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D” CIRCUIT HIGH INPUT

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

• Erroneous idling

• Poor driving performance

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK ACCELERATOR PEDAL POSITION SENSOR OUTPUT.

1) Turn the ignition switch to ON.

2) Read the data of main accelerator pedal position sensor signal using Subaru Select Monitor.

NOTE:

For detailed operation procedure, refer to “READ CURRENT DATA FOR ENGINE”.

Is the voltage less than 4.8 V?

2.CHECK POOR CONTACT.

Check poor contact of connector between ECM and accelerator pedal position sensor.

Is there poor contact?

Repair the poor contact.

Temporary poor contact occurred, but it is normal at present.

3.CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM.

3) Disconnect the connectors from accelerator pedal position sensor.

4) Measure the resistance between ECM connector and accelerator pedal position sensor connector.

Connector & terminal

(B135) No. 21 — (B315) No. 4:

(B135) No. 29 — (B315) No. 5:

(B135) No. 23 — (B315) No. 6:

Is the resistance less than 1 Ω?

Repair the open circuit of harness connector.

4.CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR.

1) Connect the ECM connector.

2) Measure the resistance between accelerator pedal position sensor connector and chassis ground.

Connector & terminal

(B315) No. 5 — Chassis ground:

Is the resistance less than 5 Ω?

Repair the poor contact of ECM connector. Replace the ECM if defective.

5.CHECK POWER SUPPLY OF ACCELERATOR PEDAL POSITION SENSOR.

1) Turn the ignition switch to ON.

2) Measure the voltage between accelerator pedal position sensor connector and chassis ground.

Connector & terminal

(B315) No. 4 (+) — Chassis ground (−):

Is the voltage between 4.5 and 5.5 V?

Repair the short circuit of harness between ECM connector and accelerator pedal position sensor connector. Replace the ECM if defective.

6.CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR.

1) Turn the ignition switch to OFF.

2) Connect the accelerator pedal position sensor connector.

3) Turn the ignition switch to ON.

4) Measure the voltage between ECM connector and chassis ground.

Connector & terminal

(B135) No. 23 (+) — Chassis ground (−):

Is the voltage less than 4.8 V?

Repair the poor contact of ECM connector. Replace the ECM if defective.

Repair the poor contact of accelerator pedal position sensor connector. Replace the accelerator pedal position sensor if defective.