ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

• Improper idling

• Engine stalls.

• Poor driving performance

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

• LHD model

• RHD model

STEP	CHECK	YES	NO
1.CHECK SENSOR OUTPUT. 1) Turn the ignition switch to ON. 2) Read the data of main throttle sensor signal using Subaru Select Monitor. 3) Check the voltage change while shaking the ECM harness and connector, engine harness connector, and electronic control throttle connector harness.	Is the voltage less than 4.63 V?
2.CHECK POOR CONTACT. Check poor contact in connector between ECM and electronic throttle.	Is there poor contact in connector between ECM and electronic throttle?	Repair the poor contact.	Temporary poor contact occurred, but it is normal at present.
3.CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE. 1) Turn the ignition switch to OFF. 2) Disconnect the connectors from the ECM. 3) Disconnect the connectors from electronic throttle. 4) Measure the resistance between ECM connector and electronic throttle connector. Connector & terminal (B134) No. 18 — (E57) No. 6: (B134) No. 29 — (E57) No. 3:	Is the resistance less than 1 Ω?		Repair the open circuit of harness connector.
4.CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE. 1) Connect the ECM connector. 2) Measure the resistance between electronic throttle connector and engine ground. Connector & terminal (E57) No. 3 — Engine ground:	Is the resistance less than 5 Ω?		Repair the poor contact of ECM connector. Replace the ECM if defective.
5.CHECK SENSOR OUTPUT POWER SUPPLY. Measure the voltage between electronic throttle connector and engine ground. Connector & terminal (E57) No. 6 (+) — Engine ground (−):	Is the voltage less than 10 V?		Repair the short to power supply in harness between ECM connector and electronic throttle connector.
6.CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE. 1) Turn the ignition switch to OFF. 2) Disconnect the connectors from the ECM. 3) Measure the resistance between ECM connectors. Connector & terminal (B134) No. 18 — (B134) No. 19:	Is the resistance 1 MΩ or more?	Repair the poor contact of harness. Replace the electronic throttle if defective.	Repair the short to power supply in harness.