DTC P0123 - Throttle/Pedal Position Sensor/Switch "A" Circuit High Input -

WARNING: This page is about a different variant/trim than selected.

DTC DETECTING CONDITION:
- Detected simultaneously at occurrence of malfunction.
TROUBLE SYMPTOM:
- Erroneous idling
- Engine stalls.
- Poor driving performance
CAUTION: After repair or replacement of malfunctioning parts, conduct Clear Memory Mode < Ref. to OPERATION , CLEAR MEMORY MODE > and INSPECTION MODE < Ref. to OPERATION , INSPECTION MODE. >
WIRING DIAGRAM:

Fig 1: Throttle/Pedal Position Sensor/Switch Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK CURRENT DATA. Start engine. Read data of throttle position sensor signal using Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR . > General scan tool For detailed operation procedures, refer to the General Scan Tool Instruction Manual.	Is the measured value more than 4.9 V?	Go to step 2.	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
2 CHECK HARNESS BETWEEN THROTTLE POSITION SENSOR AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect connector from throttle position sensor. Measure resistance of harness between throttle position sensor connector and engine ground. Connector & terminal (E13) No. 2 - Engine ground:	Is the measured value less than 5 Ω?	Go to step 3.	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 Poor contact in joint connector
3 CHECK HARNESS BETWEEN THROTTLE POSITION SENSOR AND ECM CONNECTOR. Turn ignition switch to ON. Measure voltage between throttle position sensor connector and engine ground. Connector & terminal (E13) No. 3 (+) - Engine ground (-):	Is the measured value more than 4.9 V?	Repair battery short circuit in harness between throttle position sensor and ECM connector. After repair, replace ECM. < Ref. to ENGINE CONTROL MODULE . >	Replace throttle position sensor. < Ref. to THROTTLE POSITION SENSOR . >