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Home >> Infiniti >> 2011 >> FX35 RWD >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Exterior Lighting System -- FX35/FX50 >> DTC/Circuit Diagnosis >> DTC B2521: Ecu Circuit >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK EACH SENSOR POWER SUPPLY
    1. Turn the ignition switch ON.
    2. Check the voltage between the AFS control unit harness connector and the ground.
      VOLTAGE REFERENCE CHART

      Terminals Voltage (Approx.)
      (+) (-)
      AFS control unit Ground
      Connector Terminal
      M16 4 5 V
      6
      24

      Is the measurement value within the standard value? 

      YES: GO TO 2.

      Less than the standard value: GO TO  3.

      Higher than the standard value: GO TO  4.

  2. CHECK EACH SENSOR SIGNAL

    Check the voltage between the AFS control unit harness connector and the ground.

    VOLTAGE REFERENCE CHART

    Terminals Voltage (Approx.)
    (+) (-)
    AFS control unit Ground
    Connector Terminal
    M16 9 0.25 - 4.75 V
    28
    29

    Is the measurement value within the standard value? 

    YES: Replace AFS control unit.

    Less than the standard value: GO TO  5.

    Higher than the standard value: GO TO  6.

  3. CHECK EACH SENSOR POWER SUPPLY SHORT CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect AFS control unit connector.
    3. Check continuity between the AFS control unit harness connector and the ground.
      CONTINUITY REFERENCE CHART

      AFS control unit Ground Continuity
      Connector Terminal
      M16 4 Not existed
      6
      24

      Does continuity exist? 

      YES: Repair the harnesses or connectors.

      NO: Replace AFS control unit.

  4. CHECK EACH SENSOR POWER SUPPLY CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect AFS control unit connector.
    3. Check the voltage between the AFS control unit harness connector and the ground.
      VOLTAGE REFERENCE CHART

      Terminals Voltage (Approx.)
      (+) (-)
      AFS control unit Ground
      Connector Terminal
      M16 4 0 V
      6
      24

      Is the measurement value normal? 

      YES: Replace AFS control unit.

      NO: Repair the harnesses or connectors.

  5. CHECK EACH SENSOR SIGNAL SHORT CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect AFS control unit connector.
    3. Check continuity between the AFS control unit harness connector and the ground.
      CONTINUITY REFERENCE CHART

      AFS control unit Ground Continuity
      Connector Terminal
      M16 9 Not existed
      28
      29

      Does continuity exist? 

      YES: Repair the harnesses or connectors.

      NO: Replace AFS control unit.

  6. CHECK EACH SENSOR SIGNAL SHORT CIRCUIT
    1. Turn the ignition switch OFF.
    2. Disconnect AFS control unit connector.
    3. Turn the ignition switch ON.
    4. Check the voltage between the AFS control unit harness connector and the ground.
      VOLTAGE REFERENCE CHART

      Terminals Voltage (Approx.)
      (+) (-)
      AFS control unit Ground
      Connector Terminal
      M16 9 0 V
      28
      29

      Is the measurement value normal? 

      YES: Replace AFS control unit.

      NO: Repair the harnesses or connectors.

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