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Home >> Infiniti >> 2012 >> M35h >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0500 To P31A5 >> DTC P1805: Brake Switch >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK STOP LAMP SWITCH CIRCUIT
    1. Turn ignition switch OFF.
    2. Check the stop lamp when depressing and releasing the brake pedal.
      Brake pedal Stop lamp
      Fully released Not illuminated
      Slightly depressed Illuminated

      Is the inspection result normal? 

      YES: GO TO  4.

      NO: GO TO 2.

  2. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT-I
    1. Disconnect stop lamp switch harness connector.
    2. Check the voltage between stop lamp switch harness connector and ground.
      Stop lamp switch Ground Voltage
      Connector Terminal
      E110 1 Ground Battery voltage

      Is the inspection result normal? 

      YES: GO TO  9.

      NO-1 (Without ICC): GO TO 3.

      NO-2 (With ICC): GO TO  4.

  3. DETECT MALFUNCTIONING PART

    Check the following.

    • Fuse block (J/B) connector E103
    • 10 A fuse (No. 7)
    • Harness for open or short between stop lamp switch and 12V battery

      : Repair open circuit, short to ground or short to power in harness or connectors.

  4. CHECK STOP LAMP OFF RELAY 1 POWER SUPPLY CIRCUIT
    1. Disconnect stop lamp off relay 1 harness connector.
    2. Check the voltage between stop lamp off relay 1 harness connector and ground.
      Stop lamp off relay 1 Ground Voltage
      Connector Terminal
      B246 3 Ground Battery voltage

      Is the inspection result normal? 

      YES: GO TO 5.

      NO: GO TO  6.

  5. DETECT MALFUNCTIONING PART

    Check the following.

    • Fuse block (J/B) connector E103
    • 10 A fuse (No. 7)
    • Harness for open or short between stop lamp switch and 12V battery

      : Repair open circuit, short to ground or short to power in harness or connectors.

  6. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT-II
    1. Check the continuity between stop lamp off relay 1 harness connector and stop lamp switch harness connector.
      Stop lamp off relay 1 Stop lamp switch Continuity
      Connector Terminal Connector Terminal
      B246 4 E110 1 Existed
    2. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  8.

      NO: GO TO 7.

  7. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors B228, B28
    • Harness connectors B69, E119
    • Harness for open or short between stop lamp off relay 1 and stop lamp switch

      : Repair open circuit, short to ground or short to power in harness or connectors.

  8. CHECK STOP LAMP OFF RELAY 1

    Refer to "COMPONENT INSPECTION (STOP LAMP OFF RELAY 1) ".

    Is the inspection result normal? 

    YES: GO TO  7.

    NO: Replace stop lamp off relay 1. Refer to "BODY HARNESS ".

  9. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Disconnect stop lamp switch harness connector.
    2. Disconnect ECM harness connector.
    3. Check the continuity between stop lamp switch harness connector and ECM harness connector.
      Stop lamp switch ECM Continuity
      Connector Terminal Connector Terminal
      E110 2 M107 122 Existed
    4. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  11.

      NO: GO TO 10.

  10. DETECT MALFUNCTIONING PART

    Check the following.

    • Fuse block (J/B) connector E103, M2
    • Harness for open or short between ECM and stop lamp switch

      : Repair open circuit, short to ground or short to power in harness or connectors.

  11. CHECK STOP LAMP SWITCH

    Refer to "COMPONENT INSPECTION (STOP LAMP SWITCH) ".

    Is the inspection result normal? 

    YES: GO TO 12.

    NO: Replace stop lamp switch. Refer to "EXPLODED VIEW ".

  12. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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