DTC P0400 Exhaust Gas RECIRCULATION Flow

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

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.
GENERAL DESCRIPTION < Ref. to DTC P0400 EXHAUST GAS RECIRCULATION FLOW , Diagnostic Trouble Code (DTC) Detecting Criteria. >

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 < Ref. to OPERATION , Clear Memory Mode. > and Inspection Mode < Ref. to PROCEDURE , Inspection Mode. >.

WIRING DIAGRAM:

Fig 1: Exhaust Gas Recirculation Flow - Wiring Diagram

DIAGNOSIS PROCEDURE

Step	Check	Yes	No
1 CHECK ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed?	Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". < Ref. to CLEAR MEMORY MODE . >	Go to step 2.
2 CHECK CURRENT DATA. Start the engine. Read data of intake manifold absolute pressure signal using Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". < Ref. to CLEAR MEMORY MODE . > General scan tool For detailed operation procedure, refer to the general scan tool operation manual.	Is the measured value more than 53.3 kPa (400 mmHg, 15.75 inHg)?	Make sure that the EGR valve, manifold absolute pressure sensor and throttle body are installed securely.	Go to step 3.
3 CHECK POWER SUPPLY OF EGR VALVE. Disconnect the connector from EGR valve. Turn the ignition switch to ON. 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 more than 10 V?	Go to step 4.	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 and 30 Ω?	Go to step 5.	Replace the EGR valve. < Ref. to EGR VALVE . >
5 CHECK OUTPUT SIGNAL FROM ECM. Turn the ignition switch to OFF. Connect the connector to ECM and EGR valve. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal: (B134) No. 10 (+) - Chassis ground (-): (B134) No. 9 (+) - Chassis ground (-): (B134) No. 8 (+) - Chassis ground (-): (B134) No. 20 (+) - Chassis ground (-):	Is the voltage 0 - 10 V?	Repair the poor contact portion of ECM connector.	Go to step 6.
6 CHECK HARNESS BETWEEN EGR VALVE AND ECM CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from EGR valve and ECM. Measure the resistance of harness between EGR valve and ECM connector. Connector & terminal: (B134) No. 10 - (E18) No. 4: (B134) No. 9 - (E18) No. 1: (B134) No. 8 - (E18) No. 3: (B134) No. 20 - (E18) No. 6:	Is the resistance less than 1 Ω?	Go to step 7.	Repair the open circuit of harness between ECM and EGR valve connector. < Ref. to EGR VALVE . >
7 CHECK HARNESS BETWEEN EGR VALVE AND ECM CONNECTOR. Measure the resistance of harness between EGR valve and chassis ground. Connector & terminal: (B134) No. 10 - Chassis ground: (B134) No. 9 - Chassis ground: (B134) No. 8 - Chassis ground: (B134) No. 20 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 8.	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.