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Home >> Nissan-Datsun >> 2005 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P1143 To P2138 (Qr25DE) >> DTC P1805: Brake Switch >> Diagnostic Procedure

Diagnostic 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 CONDITION AND STOP LAMP ILLUMINATION DETAIL

      Brake pedal Stop lamp
      Fully released Not illuminated
      Slightly depressed Illuminated

    OK or NG 

    1. OK : GO TO  4.
    2. NG : GO TO 2.
  2. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 
    1. Disconnect stop lamp switch harness connector.
      Fig 1: Identifying Stop Lamp Switch And Brake Pedal
      G02454214Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-II or tester.
      Fig 2: Checking Voltage Between Stop Lamp Switch Connector Terminal 1 And Ground
      G02454215Courtesy of NISSAN MOTOR CO., U.S.A.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK : GO TO  4.
    2. NG : GO TO 3.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • 10A fuse
    • Fuse block (J/B) connector M2
    • Harness for open or short between stop lamp switch and battery
      1. : Repair open circuit or short to ground or short to power in harness or connectors.
  4. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Disconnect stop lamp switch harness connector.
    3. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 2

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.
    Fig 3: Identifying Stop Lamp Switch And Brake Pedal
    G02454216Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO TO  6.
    2. NG : GO TO 5.
  5. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M59, F27
    • Harness for open or short between ECM and stop lamp switch
      1. : Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK STOP LAMP SWITCH 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    1. OK : GO TO 7.
    2. NG : Replace stop lamp switch.
  7. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    1. : INSPECTION END