ENGINE (DIAGNOSTICS)(H4SO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

• Movement performance problem when engine is low speed.

• Erroneous idling

• Movement performance problem

CAUTION:

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

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK ANY OTHER DTC ON DISPLAY.	Is there any other DTC displayed?	Check DTC using “List of Diagnostic Trouble Code (DTC)”.
2.CHECK CURRENT DATA. 1) Start the engine. 2) Read the data of intake manifold absolute pressure signal using Subaru Select Monitor. NOTE: For detailed operation procedure, refer to “READ CURRENT DATA FOR ENGINE”.	Is the measured value 53.3 kPa (400 mmHg, 15.75 inHg) or more?	Make sure that the EGR valve, manifold absolute pressure sensor and throttle body are installed securely.
3.CHECK POWER SUPPLY OF EGR VALVE. 1) Disconnect the connector from EGR valve. 2) Turn the ignition switch to ON. 3) Measure the voltage between EGR valve connector and engine ground. Connector & terminal (E18) No. 2 (+) — Engine ground (−): (E18) No. 5 (+) — Engine ground (−):	Is the voltage 10 V or more?		Repair the open circuit of harness between main relay and EGR valve connector.
4.CHECK EGR VALVE. Measure the resistance between EGR valve terminals. NOTE: Make sure there is no foreign material between EGR valve and valve seat. Terminals No. 1 — No. 2: No. 3 — No. 2: No. 4 — No. 5: No. 6 — No. 5:	Is the resistance between 20 — 30 Ω?		Replace the EGR valve.
5.CHECK OUTPUT SIGNAL OF ECM. 1) Turn the ignition switch to OFF. 2) Connect the connector to ECM and EGR valve. 3) Turn the ignition switch to ON. 4) Measure the voltage between ECM and chassis ground. Connector & terminal (B134) No. 8 (+) — Chassis ground (−): (B134) No. 9 (+) — Chassis ground (−): (B134) No. 10 (+) — Chassis ground (−): (B134) No. 20 (+) — Chassis ground (−):	Is the voltage 0 — 10 V?	Repair the poor contact portion of ECM connector.
6.CHECK HARNESS BETWEEN EGR VALVE AND ECM CONNECTOR. 1) Turn the ignition switch to OFF. 2) Disconnect the connector from EGR valve and ECM. 3) Measure the resistance of harness between EGR valve and ECM connector. Connector & terminal (B134) No. 20 — (E18) No. 6: (B134) No. 9 — (E18) No. 1: (B134) No. 10 — (E18) No. 4: (B134) No. 8 — (E18) No. 3:	Is the resistance less than 1 Ω?		Repair the open circuit of harness between ECM and EGR valve connector.
7.CHECK HARNESS BETWEEN EGR VALVE AND ECM CONNECTOR. Measure the resistance of harness between EGR valve and chassis ground. Connector & terminal (B134) No. 8 — Chassis ground: (B134) No. 9 — Chassis ground: (B134) No. 10 — Chassis ground: (B134) No. 20 — Chassis ground:	Is the resistance 1 MΩ or more?		Repair the short circuit of harness between main relay and EGR valve connector.
8.CHECK POOR CONTACT. Check poor contact of ECM and EGR valve connectors.	Is there poor contact in ECM and EGR valve connector?	Repair the poor contact of ECM and EGR valve connectors.	Even if the malfunction indicator light illuminates, the circuit has returned to the specified condition at this time.