DTC P0400 - Exhaust Gas RECIRCULATION Flow -

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

DTC DETECTING CONDITION:
- Two consecutive driving cycles with malfunction
TROUBLE SYMPTOM:
- Poor driving performance on low engine speed
- Erroneous idling
- 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: Exhaust Gas Recirculation Flow Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed?	Inspect the relevant DTC using "List of Diagnostic Trouble Code (DTC)". < Ref. to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . >	Go to step 2.
2 CHECK CURRENT DATA. Start engine. Rear the data of intake manifold absolute pressure 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 53.3 kPa (400 mmHg, 15.75 inHg)?	Check if EGR valve, intake manifold pressure sensor and throttle body are securely installed.	Go to step 3.
3 CHECK POWER SUPPLY TO EGR SOLENOID VALVE. Disconnect connector from EGR solenoid valve. Turn ignition switch to ON. Measure voltage between EGR solenoid valve and engine ground. Connector & terminal (E18) No. 2 - Engine ground: (E18) No. 5 - Engine ground:	Is the measured value more than 10 V?	Go to step 4.	Repair open circuit in harness between main relay and EGR solenoid valve connector.
4 CHECK EGR SOLENOID VALVE. Measure resistance between EGR solenoid valve terminals. NOTE: Make sure there are no foreign objects caught between EGR solenoid valve and valve seat. Terminals No. 1 - No. 2: No. 3 - No. 2: No. 4 - No. 5: No. 6 - No. 5:	Is the measured value within 20 to 30 Ω?	Go to step 5.	Replace EGR solenoid valve. < Ref. to EGR VALVE . >
5 CHECK OUTPUT SIGNAL FROM ECM. Turn ignition switch to OFF. Connect connectors to ECM and EGR solenoid valve. Turn ignition switch to ON. Measure voltage between ECM and chassis ground. Connector & terminal (B134) No. 15 - Chassis ground: (B134) No. 16 - Chassis ground: (B134) No. 17 - Chassis ground: (B134) No. 18 - Chassis ground:	Does the measured value change within 0 to 10 V?	Repair poor contact in ECM connector.	Go to step 6.
6 CHECK HARNESS BETWEEN EGR SOLENOID VALVE AND ECM CONNECTOR. Turn ignition switch to OFF. Disconnect connectors from EGR solenoid valve and ECM. Measure resistance of harness between EGR solenoid valve and ECM connector. Connector & terminal (B134) No. 18 - (E18) No. 6: (B134) No. 17-(E18) No. 1: (B134) No. 16 - (E18) No. 4: (B134) No. 15 - (E18) No. 3:	Is the measured value less than 1 Ω?	Go to step 7.	Repair open circuit in harness between ECM and EGR solenoid valve connector.
7 CHECK HARNESS BETWEEN EGR SOLENOID VALVE AND ECM CONNECTOR. Measure resistance of harness between EGR solenoid valve and chassis ground. Connector & terminal (E18) No. 1 - Chassis ground: (E18) No. 3 - Chassis ground: (E18) No. 4 - Chassis ground: (E18) No. 6 - Chassis ground:	Is the measured value more than 1 MΩ?	Go to step 8.	Repair short circuit in harness between main relay and EGR solenoid valve connector.
8 CHECK POOR CONTACT. Check poor contact in ECM and EGR solenoid valve connector.	Is there poor contact in ECM and EGR solenoid valve connector?	Repair poor contact in ECM and EGR solenoid valve connector.	Even if MIL lights up, the circuit has returned to a normal condition at this time.