P0123

DTC P0123 - THROTTLE POSITION SENSOR CIRCUIT HIGH INPUT

DTC DETECTING CONDITION:
- Immediately at fault recognition.

TROUBLE SYMPTOM:
- Erroneous idling.
- Engine stalls.
- Poor driving performance.

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE and INSPECTION MODE. Refer to How To Clear Diagnostic Trouble Codes. Clear Memory Mode




WIRING DIAGRAM

10L1 CHECK CURRENT DATA.
1. Start engine.
2. Read data of throttle position sensor signal using Subaru Select Monitor or OBD-II general scan tool.

NOTE:
- Subaru Select Monitor
For detailed operation procedure, Refer to the "READ CURRENT DATA SHOWN ON DISPLAY FOR ENGINE". Refer to Normal Scan Data Values.
- OBD-II general scan tool
For detailed operation procedures, Refer to the OBD-II General Scan Tool Instruction Manual.

CHECK: Is the value more than 4.9 V?

YES: Go to step 10L2.

NO: Even if MIL lights up, the circuit has returned to a normal condition at this time. A temporary poor contact of the connector may be the cause.

NOTE:
In this case, repair the following:
- Poor contact in throttle position sensor connector.
- Poor contact in ECM connector.
- Poor contact in coupling connector (B21).

10L2: CHECK HARNESS BETWEEN THROTTLE POSITION SENSOR AND ECM CONNECTOR.
1. Turn ignition switch to OFF.
2. Disconnect connector from throttle position sensor.

Connector & Terminal (E13) No.2 - Engine ground:

3. Measure resistance of harness between throttle position sensor connector and engine ground.

CHECK: Is the resistance less than 5 ohms?

YES: Go to step 10L3.

NO: Repair harness and connector.

NOTE:
In this case, repair the following:
- Open circuit in harness between throttle position sensor and ECM connector.
- Poor contact in coupling connector (B21).
- Poor contact in joint connector (B122).

10L3: CHECK HARNESS BETWEEN THROTTLE POSITION SENSOR AND ECM CONNECTOR.
1. Turn ignition switch to ON.

Connector & Terminal (E13) No.3 (+) - Engine ground (-):

2. Measure voltage between throttle position sensor connector and engine ground.

CHECK: Is the voltage more than 4.9 V?

YES: Repair battery short circuit in harness between throttle position sensor and ECM connector. After repair, replace ECM.

NO: Replace throttle position sensor.