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

DTC DETECTING CONDITION:

Immediately at fault recognition
GENERAL DESCRIPTION < Ref. to DTC P2123 THROTTLE/PEDAL POSITION SENSOR/SWITCH "D" CIRCUIT HIGH INPUT , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Erroneous idling
Poor driving performance

CAUTION: After repair or replacement of faulty parts, conduct Clear Memory Mode < Ref. to , OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to , PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM:

Fig 1: Wiring Diagram - Throttle/Pedal Position Sensor Circuit (High Input)

Courtesy of SUBARU OF AMERICA, INC.

DTC P2123 DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK OUTPUT VOLTAGE OF ACCELERATOR PEDAL POSITION SENSOR. Turn the ignition switch to ON. Read the data of main accelerator pedal position sensor signals, using Subaru Select Monitor. Shake the ECM harness and connector, engine harness connector, accelerator pedal position sensor connector harness while monitoring value of voltage meter.	Is the voltage less than 4.8 V?	Go to step 2 .	Go to step 3 .
2 CHECK POOR CONTACT IN CONNECTORS. Check poor contact in connectors between ECM and accelerator pedal position sensor.	Is there any poor contact in connectors between ECM and accelerator pedal position sensor?	Repair the poor contact in connectors.	Connector has returned to its normal condition at this time. A temporary poor contact in the connector might have been the cause.
3 CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR. Turn the ignition switch to OFF. Disconnect the connector from ECM. Disconnect the connector from accelerator pedal position sensor. Measure the resistance between ECM connector and accelerator pedal position sensor. Connector & terminal (B136) No. 34 - (B315) No. 4:	Is the resistance less than 1 Ω?	Go to step 4 .	Repair the open harness connector.
4 CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR. Connect the ECM connector. Measure the resistance between accelerator pedal position sensor and engine ground. Connector & terminal (B315) No. 4 - Engine ground:	Is the resistance less than 5 Ω?	Go to step 5 .	Repair the poor contact in ECM connector. If problem persists, replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . >
5 CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR. Connect the ECM connector. Turn the ignition switch to ON. Measure the voltage between accelerator pedal position sensor connector and engine ground. Connector & terminal (B315) No. 3 (+) - Engine ground (-): Shake the ECM harness and connector, while monitoring value of voltage meter.	Is the voltage more than 6 V?	Go to step 6 .	Repair the battery short of harness between ECM connector and accelerator pedal position sensor.
6 CHECK POWER SUPPLY TO ACCELERATOR PEDAL POSITION SENSOR. Measure the voltage between accelerator pedal position sensor connector and engine ground. Connector & terminal (B315) No. 5 (+) - Engine ground (-): Shake the ECM harness and connector, while monitoring value of voltage meter.	Is the voltage less than 4.8 V?	Go to step 7 .	Repair the short of harness between ECM connector and accelerator pedal position sensor connector.
7 CHECK HARNESS BETWEEN ECM AND ACCELERATOR PEDAL POSITION SENSOR. Turn the ignition switch to OFF. Connect the accelerator pedal position sensor connector. Turn the ignition switch to ON. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B136) No. 17(+) - Chassis ground (-):	Is the voltage 4.8 V?	Repair the poor contact in ECM connector. If problem persists, replace the ECM. < Ref. to ENGINE CONTROL MODULE (ECM) . >	Repair the poor contact in electronic throttle control connector. If problem persists, replace the electronic throttle control.