Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P2404 EVAP System Leak Detection Pump Sense Circuit Range/Performance: Wiring Diagram
2016 Subaru Legacy 2.5iSECTION Wiring Diagram
- Engine Electrical System ENGINE TYPE FB (WITHOUT PUSH BUTTON START) < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >
- Engine Electrical System ENGINE TYPE FB (WITH PUSH BUTTON START) < Ref. to appropriate wiring diagram in SYSTEM WIRING DIAGRAM article. >
DIAGNOSTIC PROCEDURE
| 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)". < Ref. 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 operation procedures, refer to the "Active Test". < Ref. to
ACTIVE TEST
. >
|
Does the ELCM pump operate? | Go to step 6 . | Go to step 3 . |
3 CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY.
|
Is the voltage 10 V or more? | Go to step 4 . | Repair the harness and connector.
NOTE:
In this case, repair the following item:
|
4 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
|
Is the resistance less than 1 Ω? | Go to step 5 . | Repair the harness and connector.
NOTE:
In this case, repair the following item:
|
5 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
|
Is the resistance 1 MΩ or more? | Replace the leak check valve assembly. < Ref. to LEAK CHECK VALVE ASSEMBLY . > | Repair the short circuit to ground in harness between ECM connector and leak check valve assembly connector. |
| 6 CHECK ELCM SWITCHING VALVE. Operate the ELCM switching valve using the Subaru Select Monitor.
NOTE:
For detailed operation procedures, refer to the "Active Test". < Ref. to
ACTIVE TEST
. >
|
Does the ELCM switching valve operate? | Go to step 10 . | Go to step 7 . |
7 CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY.
|
Is the voltage 10 V or more? | Go to step 8 . | Repair the harness and connector.
NOTE:
In this case, repair the following item:
|
8 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
|
Is the resistance less than 1 Ω? | Go to step 9 . | Repair the harness and connector.
NOTE:
In this case, repair the following item:
|
9 CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
|
Is the resistance 1 MΩ or more? | Replace the leak check valve assembly. < Ref. to LEAK CHECK VALVE ASSEMBLY . > | Repair the short circuit to ground in harness between ECM connector and leak check valve assembly connector. |
| 10 CHECK EVAPORATIVE EMISSION CONTROL SYSTEM. Perform drive cycle I. < Ref. to DRIVE CYCLE I , PROCEDURE, Drive Cycle. > |
Is DTC P2404 displayed on the display? | Replace the leak check valve assembly. < Ref. 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.
|
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.