DTC P2404 EVAP System Leak Detection Pump Sense Circuit Range/Performance: Notes

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Fig 1: EVAP System Leak Detection Pump Sense Circuit Range/Performance - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

CHECK FOR ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?
- Yes : Check the appropriate DTC using the "List of Diagnostic Trouble Code (DTC)". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>List of Diagnostic Trouble Code (DTC) .
- No : Go to 2.
CHECK LEAK CHECK VALVE ASSEMBLY PUMP.
Using the Subaru Select Monitor, operate the leak check valve assembly pump.

NOTE: For detailed procedures, refer to "Active Test". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Active Test .

Does the leak check valve assembly pump operate?
- Yes : Go to 6.
- No : Go to 3.
CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the leak check valve assembly.
3. Turn the ignition switch to ON.
4. 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?
- Yes : Go to 4.
- No : 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
CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance of harness between ECM and the leak check valve assembly connector.
Connector & terminal

(B134) No. 3 - (R400) No. 4:

Is the resistance less than 1 Ω?
- Yes : Go to 5.
- No : 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
CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
1. Measure the resistance of harness between ECM and chassis ground.
  Connector & terminal
  
  (B134) No. 3 - Chassis ground:
  
  Is the resistance 1 MΩ or more?
- Yes : Replace the leak check valve assembly. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DOTC)>Leak Check Valve Assembly .
- No : Repair the short circuit to ground in harness between ECM and leak check valve assembly connector.
CHECK LEAK CHECK VALVE ASSEMBLY SWITCHING VALVE.
Using the Subaru Select Monitor, operate the leak check valve assembly switching valve.

NOTE: For detailed procedures, refer to "Active Test". Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Active Test .

Does the leak check valve assembly switching valve operate?
- Yes : Go to 10.
- No : Go to 7.
CHECK POWER SUPPLY OF LEAK CHECK VALVE ASSEMBLY.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from the leak check valve assembly.
3. Turn the ignition switch to ON.
4. 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?
- Yes : Go to 8.
- No : 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
CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance of harness between ECM and the leak check valve assembly connector.
  Connector & terminal
  
  (B134) No. 27 - (R400) No. 1:
  
  Is the resistance less than 1 Ω?
- Yes : Go to 9.
- No : 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
CHECK HARNESS BETWEEN ECM AND LEAK CHECK VALVE ASSEMBLY CONNECTOR.
1. Measure the resistance of harness between ECM and chassis ground.
  Connector & terminal
  
  (B134) No. 27 - Chassis ground:
  
  Is the resistance 1 MΩ or more?
- Yes : Replace the leak check valve assembly. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DOTC)>Leak Check Valve Assembly .
- No : Repair the short circuit to ground in harness between ECM and leak check valve assembly connector.
CHECK EVAPORATIVE EMISSION CONTROL SYSTEM.
Perform drive cycle I. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Drive Cycle>PROCEDURE>DRIVE CYCLE I .

Is DTC P2404 displayed on the display?
- Yes : Replace the leak check valve assembly. Ref. to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (H4DOTC)>Leak Check Valve Assembly .
- No : Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis.
  NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.