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. Clearing Diagnostic Trouble Codes





WIRING DIAGRAM

10L1: CONNECT SUBARU SELECT MONITOR OR THE OBD-II GENERAL SCAN TOOL, AND READ DATA.

1) Turn ignition switch to OFF.





2) Connect Subaru Select Monitor or the OBD-II general scan tool to data link connector.

3) Turn ignition switch to ON and Subaru Select Monitor or OBD-II general scan tool switch to ON.

4) Start engine.

5) 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".
- 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 (B22)

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 (B22)

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.