DTC P2404 Evaporative Emission System Leak Detection Pump Sense Circuit Range/Performance: Wiring Diagram

Engine electrical system, 2.5 L model (without push button start). See appropriate SYSTEM WIRING DIAGRAM article.
Engine electrical system, 2.5 L model (with push button start). See appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: Evaporative Emission System Pressure Sensor/Switch - Circuit Diagram
Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK FOR ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed?	Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Refer to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) .	Go to step 2 .
2 CHECK ELCM PUMP. Operate the ELCM pump using the Subaru Select Monitor. NOTE: For detailed procedures, refer to SYSTEM OPERATION CHECK MODE .	Does the ELCM pump operate?	Go to step 6 .	Go to step 3 .
3 CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY. Turn the ignition switch to OFF. Disconnect the connector from the leak check valve assembly. Turn the ignition switch to ON. Measure the voltage between the leak check valve assembly connector and chassis ground. Connector & terminal (R400) No. 3 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 4 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between the main relay and the leak check valve assembly connector Poor contact of main relay connector Poor contact of coupling connector
4 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from ECM. Measure the resistance of harness between ECM and the leak check valve assembly connector. Connector & terminal (B135) No. 8 - (R400) No. 4:	Is the resistance less than 1 Ω?	Go to step 5 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between ECM and the leak check valve assembly connector Poor contact of coupling connector
5 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR. Measure the resistance of harness between ECM and chassis ground. Connector & terminal (B135) No. 8 - Chassis ground:	Is the resistance 1 MΩ or more?	Replace the leak check valve assembly. Refer to LEAK CHECK VALVE ASSEMBLY .	Repair the short circuit to ground in harness between ECM and leak check valve assembly connector.
6 CHECK ELCM SWITCHING VALVE. Operate the ELCM switching valve using the Subaru Select Monitor. NOTE: For detailed procedures, refer to SYSTEM OPERATION CHECK MODE .	Does the ELCM switching valve operate?	Go to step 10 .	Go to step 7 .
7 CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY. Turn the ignition switch to OFF. Disconnect the connector from the leak check valve assembly. Turn the ignition switch to ON. Measure the voltage between the leak check valve assembly connector and chassis ground. Connector & terminal (R400) No. 5 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 8 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between the main relay and the leak check valve assembly connector Poor contact of main relay connector Poor contact of coupling connector
8 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from ECM. Measure the resistance of harness between ECM and the leak check valve assembly connector. Connector & terminal (B135) No. 1 - (R400) No. 1:	Is the resistance less than 1 Ω?	Go to step 9 .	Repair the harness and connector. NOTE: In this case, repair the following item: Open circuit in harness between ECM and the leak check valve assembly connector Poor contact of coupling connector
9 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR. Measure the resistance of harness between ECM and chassis ground. Connector & terminal (B135) No. 1 - Chassis ground:	Is the resistance 1 MΩ or more?	Replace the leak check valve assembly. Refer to LEAK CHECK VALVE ASSEMBLY .	Repair the short circuit to ground in harness between ECM and leak check valve assembly connector.
10 CHECK EVAPORATIVE EMISSION CONTROL SYSTEM. Perform drive cycle I. Refer to DRIVE CYCLE I .	Is DTC P2404 displayed on the display?	Replace the leak check valve assembly. Refer to LEAK CHECK VALVE ASSEMBLY .	Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again. NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.