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Home >> Nissan-Datsun >> 2004 >> Sentra SE-R >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Qr25DE >> DTC P1805: Brake Switch >> Diagnostic Procedure
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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.
    Fig 1: Stop Lamp & Brake Pedal Conditions
    G00779463Courtesy of NISSAN MOTOR CO., U.S.A.

    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 2: Disconnecting Stop Lamp Switch Harness Connector
      G00779464Courtesy of NISSAN MOTOR CO., U.S.A.
    2. Check voltage between stop lamp switch terminal 1 (A/T models), + (M/T models) and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    Fig 3: Check Voltage Between Stop Lamp Switch Terminal 1 & Ground (A/T Models)
    G00779465Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 4: Check Voltage Between Stop Lamp Switch Terminal + & Ground (M/T Models)
    G00779466Courtesy of NISSAN MOTOR CO., U.S.A.

    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. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect stop lamp switch harness connector.
    4. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 2 (A/T models), - (M/Y models).

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    5. Also check harness for short to ground and short to power.
    6. Fig 5: Disconnecting Stop Lamp Switch Harness Connector
      G00779467Courtesy 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