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DTC P257E: Engine Hood Switch Circuit Low: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

Auto Start Stop does not operate.

CAUTION: After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure. Ref. to AUTO START STOP (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .

Wiring diagram: 

Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP .

G14414952Courtesy of SUBARU OF AMERICA, INC.
  1. CHECK DATA MONITOR  .
    1. Turn the ignition switch to ON.
    2. Read the data of [Hood SW (Hood Open Status)] with the front hood closed using the Subaru Select Monitor. Ref. to AUTO START STOP (DIAGNOSTICS)>DATA MONITOR .

      Data Monitor 

    Is [OFF] displayed in [Hood SW (Hood Open Status)]?

    Yes:  Go to  2.

    No:  Go to  3.

  2. CHECK DATA MONITOR  .
    1. Read the data of [Hood SW (Hood Close Status)] with the front hood opened using the Subaru Select Monitor. Ref. to AUTO START STOP (DIAGNOSTICS)>DATA MONITOR .

    Is [OFF] displayed in [Hood SW (Hood Close Status)]?

    Yes:  The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

    No:  Go to  5.

  3. CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND HOOD SWITCH (OPEN SIDE) CONNECTOR  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector of body integrated unit.
    3. Disconnect the connector of hood switch.
    4. Measure the resistance between body integrated unit connector and chassis ground.

      Connector & terminal 

      (i81) No. 7 - Chassis ground:

    Is the resistance 1 MΩ or more?

    Yes:  Go to  4.

    No:  Repair the ground short circuit of harness between body integrated unit and hood switch (open side) connector.

  4. CHECK HOOD SWITCH (OPEN SIDE) CONNECTOR  .
    1. Connect all connectors.
    2. Check continuity in hood switch (open side) connector.

      Connector & terminal 

      (B329) No. 3 - (B329) No. 2:

    Is there continuity when the front hood is closed?

    Yes:  Replace the front hood lock assembly. Ref. to SECURITY AND LOCKS>FRONT HOOD LOCK ASSEMBLY .

    No:  Check for poor contact of the body integrated unit connector and hood switch (open side) connector. If there is no abnormality, replace the body integrated unit. Ref. to SECURITY AND LOCKS>BODY INTEGRATED UNIT .

  5. CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND HOOD SWITCH (CLOSED SIDE) CONNECTOR  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector of body integrated unit.
    3. Disconnect the connector of hood switch.
    4. Measure the resistance between body integrated unit connector and chassis ground.

      Connector & terminal 

      (B281) No. 3 - Chassis ground:

    Is the resistance 1 MΩ or more?

    Yes:  Go to  6.

    No:  Repair the ground short circuit of harness between body integrated unit and hood switch (closed side) connector.

  6. CHECK HOOD SWITCH (CLOSED SIDE) CONNECTOR  .
    1. Connect all connectors.
    2. Check continuity in the hood switch (closed side) connector.

      Connector & terminal 

      (B329) No. 1 - (B329) No. 2:

    Is there continuity when the front hood is open?

    Yes:  Replace the front hood lock assembly. Ref. to SECURITY AND LOCKS>FRONT HOOD LOCK ASSEMBLY .

    No:  Check for poor contact of the body integrated unit connector and hood switch (closed side) connector. If there is no abnormality, replace the body integrated unit. Ref. to SECURITY AND LOCKS>BODY INTEGRATED UNIT .

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