LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2017 >> QX80 Base, RWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Drivers Assistance Systems - ADAS >> Driver Assistance System (ADAS Control Unit) (Introduction, Wiring Diagrams And Basic Inspection) >> DTC/Circuit Diagnosis >> C1A13 Stop Lamp Relay >> ADAS Control Unit >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK DTC PRIORITY

    If DTC "C1A13" is displayed with DTC "U1000", first diagnose the DTC "U1000".

    Is applicable DTC detected?

    YES 

    Perform diagnosis of applicable. Refer to DTC DESCRIPTION .

    NO 

    GO TO STEP 2  .

  2. CHECK STOP LAMP SWITCH

    Check that "STOP LAMP SW" operate normally in "DATA MONITOR" of "ICC/ADAS".

    Is the inspection result normal?

    YES 

    GO TO STEP  10.

    NO 

    GO TO STEP 3  .

  3. CHECK STOP LAMP SWITCH INSTALLATION

    1. Turn ignition switch OFF.
    2. Check stop lamp switch for correct installation. Refer to INSPECTION AND ADJUSTMENT .

    Is the inspection result normal?

    YES 

    GO TO STEP 4. 

    NO 

    Adjust stop lamp switch installation. Refer to INSPECTION AND ADJUSTMENT .

  4. CHECK STOP LAMP SWITCH

    1. Disconnect stop lamp switch connector.
    2. Check stop lamp switch. Refer to COMPONENT INSPECTION (STOP LAMP SWITCH) .

    Is the inspection result normal?

    YES 

    GO TO STEP 5. 

    NO 

    Replace stop lamp switch.

  5. CHECK STOP LAMP FOR ILLUMINATION

    1. Connect stop lamp switch connector.
    2. Remove ICC brake hold relay.
    3. Check that the stop lamp is illuminated by depressing the brake pedal to turn the stop lamp ON.

    Is the inspection result normal?

    YES 

    GO TO STEP 6. 

    NO 

    Check the stop lamp circuit, and repair or replace the malfunctioning parts.

  6. CHECK HARNESS BETWEEN STOP LAMP SWITCH AND ECM

    1. Turn the ignition switch OFF.
    2. Disconnect stop lamp switch, ECM, rear combination lamp, and high-mounted stop lamp connectors.
    3. Check for continuity between the stop lamp switch harness connector and the ECM harness connector.
      Stop lamp switch ECM Continuity
      Connector Terminal Connector Terminal
      E115 2 E20 139 Existed
    4. Check for continuity between stop lamp switch harness connector and ground.
      Stop lamp switch Ground Continuity
      Connector Terminal
      E115 2 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 7. 

    NO 

    Repair the harnesses or connectors.

  7. CHECK ICC BRAKE HOLD RELAY CIRCUIT

    1. Connect ICC brake hold relay, ECM, rear combination lamp, and high-mounted stop lamp connectors.
    2. Check that the stop lamp does not illuminate when brake pedal is not depressed.

    Is the inspection result normal?

    YES 

    GO TO STEP 9. 

    NO 

    GO TO STEP 8. 

  8. CHECK ICC BRAKE HOLD RELAY

    1. Remove ICC brake hold relay.
    2. Check ICC brake hold relay. Refer to COMPONENT INSPECTION .

    Is the inspection result normal?

    YES 

    GO TO STEP 9. 

    NO 

    Replace ICC brake hold relay.

  9. PERFORM SELF-DIAGNOSIS OF ECM

    1. Connect all connectors again if the connectors are disconnected.
    2. Turn ignition switch ON.
    3. Perform "All DTC Reading".
    4. Check if any DTC is detected in "Self Diagnostic Result" of "ENGINE". Refer to DTC INDEX .

    Is any DTC detected?

    YES 

    Repair or replace the malfunctioning parts identified by the self-diagnosis result.

    NO 

    Replace ADAS control unit. Refer to REMOVAL AND INSTALLATION .

  10. CHECK ICC BRAKE HOLD RELAY POWER SUPPLY CIRCUIT

    1. Turn ignition switch OFF.
    2. Remove ICC brake hold relay.
    3. Check the voltage between ICC brake hold relay harness connector and ground.
      Terminal Voltage
      (Approx.)
      (+) (-)
      ICC brake hold relay Ground
      Connector Terminal
      E64 3 Battery voltage

    Is the inspection result normal?

    YES 

    GO TO STEP 11. 

    NO 

    Repair or replace ICC brake hold relay power supply circuit.

  11. CHECK HARNESS BETWEEN AND ICC BRAKE HOLD RELAY AND ADAS CONTROL UNIT

    1. Disconnect ADAS control unit connectors.
    2. Check for continuity between ICC brake hold relay harness connector and ADAS control unit harness connector.
      ICC brake hold relay ADAS control unit Continuity
      Connector Terminal Connector Terminal
      E64 2 B52 17 Existed
    3. Check for continuity between ADAS control unit harness connector and ground.
      ICC brake hold relay Ground Continuity
      Connector Terminal
      E64 2 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 12. 

    NO 

    Repair the harnesses or connectors.

  12. CHECK ADAS CONTROL UNIT STANDARD VOLTAGE

    1. Connect all connectors again if the connectors are disconnected.
    2. Turn ignition switch ON.
    3. Perform "STOP LAMP" on "Active Test" of "ICC/ADAS", and then check the voltage between ADAS control unit harness connector and ground.
      Terminal Condition Voltage
      (Approx.)
      (+) (-)
      ADAS control unit Ground Active Test item
      "STOP LAMP"
      Connector Terminal
      B52 17 Off Battery voltage
      On 0 V

    Is the inspection result normal?

    YES 

    GO TO STEP 13. 

    NO 

    Replace ADAS control unit. Refer to REMOVAL AND INSTALLATION .

  13. CHECK ICC BRAKE HOLD RELAY POWER SUPPLY CIRCUIT

    1. Turn ignition switch OFF.
    2. Check the voltage between ICC brake hold relay harness connector and ground.
      Terminal Voltage
      (Approx.)
      (+) (-)
      ICC brake hold relay Ground
      Connector Terminal
      E64 3 Battery voltage

    Is the inspection result normal?

    YES 

    GO TO STEP 14. 

    NO 

    Repair or replace ICC brake hold relay power supply circuit.

  14. CHECK HARNESS BETWEEN ICC BRAKE HOLD RELAY AND ECM

    1. Disconnect ECM, rear combination lamp, and high-mounted stop lamp connectors and remove ICC brake hold relay.
    2. Check for continuity between ICC brake hold relay harness connector and ECM harness connector.
      ICC brake hold relay ECM Continuity
      Connector Terminal Connector Terminal
      E64 5 E20 139 Existed
    3. Check for continuity between ICC brake hold relay harness connector and ground.
      ICC brake hold relay Ground Continuity
      Connector Terminal
      E64 5 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 15. 

    NO 

    Repair the harnesses or connectors.

  15. CHECK ICC BRAKE HOLD RELAY

    1. Remove ICC brake hold relay.
    2. Check ICC brake hold relay. Refer to COMPONENT INSPECTION .

    Is the inspection result normal?

    YES 

    GO TO STEP 16. 

    NO 

    Replace ICC brake hold relay.

  16. CHECK STOP LAMP SWITCH

    Check that "STOP LAMP SW" operate normally in "DATA MONITOR" of "ABS".

    Is the inspection result normal?

    YES 

    GO TO STEP  21.

    NO 

    GO TO STEP 17  .

  17. CHECK STOP LAMP SWITCH INSTALLATION

    1. Turn ignition switch OFF.
    2. Check stop lamp switch for correct installation. Refer to INSPECTION AND ADJUSTMENT .

    Is the inspection result9normal?

    YES 

    GO TO STEP 18. 

    NO 

    Adjust stop lamp switch installation. Refer to INSPECTION AND ADJUSTMENT .

  18. CHECK STOP LAMP SWITCH

    1. Disconnect stop lamp switch connector.
    2. Check stop lamp switch. Refer to COMPONENT INSPECTION (STOP LAMP SWITCH) .

    Is the inspection result normal?

    YES 

    GO TO STEP 19. 

    NO 

    Replace stop lamp switch.

  19. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT

    1. Connect stop lamp switch connector.
    2. Check the voltage between stop lamp switch harness connector and ground.
      Terminal Voltage
      (Approx.)
      (+) (-)
      Stop lamp switch Ground
      Connector Terminal
      E115 1 Battery voltage
      3

    Is the inspection result normal?

    YES 

    GO TO STEP 20. 

    NO 

    Repair or replace stop lamp switch power supply circuit.

  20. CHECK HARNESS BETWEEN STOP LAMP SWITCH AND ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)

    1. Turn the ignition switch OFF.
    2. Disconnect stop lamp switch, ABS actuator and electric unit (control unit), and resistor connectors.
    3. Check for continuity between the stop lamp switch harness connector and the ABS actuator and electric unit (control unit) harness connector.
      Stop lamp switch ABS actuator and electric unit (control unit) Continuity
      Connector Terminal Connector Terminal
      E115 4 E36 17 Existed
    4. Check for continuity between stop lamp switch harness connector and ground.
      Stop lamp switch Ground Continuity
      Connector Terminal
      E115 4 Not existed

    Is the inspection result normal?

    YES 

    GO TO STEP 21. 

    NO 

    Repair the harnesses or connectors.

  21. PERFORM SELF-DIAGNOSIS OF ECM

    1. Connect all connectors again if the connectors are disconnected.
    2. Turn ignition switch ON.
    3. Perform "All DTC Reading".
    4. Check if any DTC is detected in "Self Diagnostic Result" of "ENGINE". Refer to DTC INDEX .

    Is any DTC detected?

    YES 

    Repair or replace the malfunctioning parts identified by the self-diagnosis result.

    NO 

    GO TO STEP 22. 

  22. PERFORM SELF-DIAGNOSIS OF ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)

    1. Connect all connectors again if the connectors are disconnected.
    2. Turn ignition switch ON.
    3. Perform "All DTC Reading".
    4. Check if any DTC is detected in "Self Diagnostic Result" of "ABS". Refer to DTC INDEX .

    Is any DTC detected?

    YES 

    Repair or replace the malfunctioning parts identified by the self-diagnosis result.

    NO 

    Replace ADAS control unit. Refer to REMOVAL AND INSTALLATION .

scientia non olet · About LEMON Manuals