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

WARNING: This page is about a different car, the 2006 Subaru Outback. However, it is still accessible from the selected car via links, so may be relevant.

DTC DETECTING CONDITION:

Immediately at fault recognition
GENERAL DESCRIPTION < Ref. to DTC P0123 THROTTLE/PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Erroneous idling
Engine stalls.
Poor driving performance

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

WIRING DIAGRAM:

Fig 1: Electronic Throttle Control - Wiring Diagram

DTC P0123 THROTTLE/PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH - DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK SENSOR OUTPUT. Turn the ignition switch to ON. Read the data of main throttle sensor signal using Subaru Select Monitor. NOTE: Subaru Select Monitor For detailed operation procedure, refer to "READ CURRENT DATA FOR ENGINE". < Ref. to SUBARU SELECT MONITOR . >	Is the voltage less than 4.63 V?	Go to step 2.	Go to step 3.
2 CHECK POOR CONTACT. Check poor contact in connector between ECM and electronic throttle control.	Is there poor contact in connector between ECM and electronic throttle control?	Repair the poor contact.	Temporary poor contact occurred, but it is normal at present.
3 CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL. Turn the ignition switch to OFF. Disconnect the connectors from ECM. Disconnect the connectors from electronic throttle control. Measure the resistance between ECM connector and electronic throttle control connector. Connector & terminal (B134) No. 18 - (E57) No. 6: (B134) No. 29 - (E57) No. 3:	Is the resistance less than 1 Ω?	Go to step 4.	Repair the open circuit of harness connector.
4 CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL. Connect the ECM connector. Measure the resistance between electronic throttle control connector and engine ground. Connector & terminal (E57) No. 3 - Engine ground:	Is the resistance less than 1 Ω?	Go to step 5.	Repair the poor contact of ECM connector. Replace the ECM if defective. < Ref. to ENGINE CONTROL MODULE (ECM) . >
5 CHECK SENSOR OUTPUT POWER SUPPLY. Measure the voltage between electronic throttle control connector and engine ground. Connector & terminal (E57) No. 6 (+) - Engine ground (-):	Is the voltage less than 10 V?	Go to step 6.	Repair the battery short circuit of harness between ECM connector and electronic throttle control connector.
6 CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL. Turn the ignition switch to OFF. Disconnect the connectors from ECM. Check the resistance between ECM connectors. Connector & terminal (B134) No. 18 - (B134) No. 19:	Is the resistance more than 1 MΩ?	Repair the poor contact of harness. Replace the electronic throttle control.	Repair the short circuit to sensor power supply.