DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The skid control ECU assembly sends a stop light operation request signal to the No. 2 integration relay. If the skid control ECU assembly detects a malfunction in the stop light relay circuit, the driving support ECU assembly stores DTC C1A4B.

DTC Code DTC Detection Condition Trouble Area
C1A4B

Diagnosis condition:


  • Power switch on (IG) and auxiliary battery voltage between 11 and 14 V

Malfunction condition:

Either of the following conditions is met:


  • When the stop light illumination output (STPO) signal is on, a signal has not been input to the STP2 terminal for 0.3 seconds or more continuously.

  • When the stop light illumination output (STPO) signal is off, signals input to the STP terminal and STP2 terminal of the skid control ECU assembly differ for 0.3 seconds or more continuously.

  • Lighting system

  • Skid control ECU assembly

  • No. 2 integration relay

  • Harness or connector

WIRING DIAGRAM

B002BCVE02

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • After replacing the skid control ECU assembly, perform zero point calibration and store the system information Click here.

  • When this DTC is output, a malfunction in the lighting system is suspected. Check if the lighting system is functioning normally Click here.

  • The pre-crash safety system uses the CAN communication system. First, confirm that there are no malfunction in the CAN communication system. Refer to How to Proceed with Troubleshooting.


  • When the start function does not operate, check the entry and start system (for start function) Click here.

PROCEDURE


  1. CHECK STOP LIGHT OPERATION


    1. Check that the stop lights come on when the brake pedal is depressed and go off when the brake pedal is released.

      OK
      The stop lights illuminate when the brake pedal is depressed. The stop lights turn off when the brake pedal is released.

    NG

    GO TO LIGHTING SYSTEM Click here

    OK

  2. INSPECT NO. 2 INTEGRATION RELAY


    1. Turn the power switch off.

    2. Inspect the No. 2 integration relay Click here.

      OK
      The No. 2 integration relay is normal.

    NG

    REPLACE NO. 2 INTEGRATION RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (STPO TERMINAL VOLTAGE)


    1. Turn the power switch off.

    2. B002BYLE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

      Disconnect the skid control ECU assembly connector.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A16-31 (STPO) - Body ground Always 11 to 14 V

    4. Connect the A16 skid control ECU assembly connector.


    NG

    CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - SKID CONTROL ECU ASSEMBLY) Click here

    OK

  4. PERFORM ACTIVE TEST USING GTS (STOP LIGHT RELAY OUTPUT)


    1. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    2. According to the display on the GTS, read the Data List item Stop Light Relay Output Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light Relay Output

      STPO terminal output condition/

      ON or OFF

      ON: Output

      OFF: Not output

      		 -

    3. Check that the Data List item Stop Light Relay Output changes between ON and OFF and the stop lights turn on and off according to the operation of the Active Test.

      Result
      Result Proceed to
      The Data List item Stop Light Relay Output does not change between ON and OFF and the stop lights do not turn ON and OFF according to the operation of the Active Test. A
      The Data List item Stop Light Relay Output changes between ON and OFF but the stop lights do not turn ON and OFF according to the operation of the Active Test. B

    B

    CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - SKID CONTROL ECU ASSEMBLY) Click here

    A

  5. INSPECT SKID CONTROL ECU ASSEMBLY


    1. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    2. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      Do not disconnect the No. 2 integration relay connector.

      Standard Voltage
      Tester Connection Condition Specified Condition
      1A-7 (ACC) - Body ground

      Power switch on (IG)

      (Active test OFF)

      		 11 to 14 V

      Power switch on (IG)

      (Active test ON)

      		 Below 1.5 V

    NG

    REPLACE SKID CONTROL ECU ASSEMBLY Click here

    OK

  6. REPLACE NO. 2 INTEGRATION RELAY


    1. Replace the No. 2 integration relay Click here.


    NEXT

  7. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END (NO. 2 INTEGRATION RELAY WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here

  8. REPLACE NO. 2 INTEGRATION RELAY


    1. Replace the No. 2 integration relay Click here.


    NEXT

  9. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END (NO. 2 INTEGRATION RELAY WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here

  10. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - SKID CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Remove the No. 2 integration relay.

    3. Disconnect the A16 skid control ECU assembly connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-7 (ACC) - A16-31 (STPO) Always Below 1 Ω
      1A-7 (ACC) or A16-31 (STPO) - Body ground Always 10 kΩ or higher

    5. Connect the A16 skid control ECU assembly connector.

    6. Install the No. 2 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  11. REPLACE NO. 2 INTEGRATION RELAY


    1. Replace the No. 2 integration relay Click here.


    NEXT

  12. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380/15 is not output. A
      DTC C1380/15 is output. B

    A

    END (NO. 2 INTEGRATION RELAY WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

  14. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END (HARNESS AND CONNECTOR WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here

  15. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - SKID CONTROL ECU ASSEMBLY)


    1. Turn the power switch off.

    2. Remove the No. 2 integration relay.

    3. Disconnect the A14 skid control ECU assembly connector.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1A-3 (STOP) - A14-24 (STP2) Always Below 1 Ω

    5. Connect the A14 skid control ECU assembly connector.

    6. Install the No. 2 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  16. REPLACE SKID CONTROL ECU ASSEMBLY


    1. Replace the skid control ECU assembly Click here.


    NEXT

  17. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END (SKID CONTROL ECU ASSEMBLY WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here

  18. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

  19. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END

    B

    GO TO DTC CHART Click here

  20. REPLACE SKID CONTROL ECU ASSEMBLY


    1. Replace the skid control ECU assembly Click here.


    NEXT

  21. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM)


    1. Clear the DTCs Click here.

    2. According to the display on the GTS, perform the Active Test Stop Light Relay Click here.

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay Stop lights ON / OFF Test possible at vehicle speed of 0 km/h (0 mph)

    3. Check for DTCs Click here.

      Result
      Result Proceed to
      DTC C1380 is not output. A
      DTC C1380 is output. B

    A

    END (SKID CONTROL ECU ASSEMBLY WAS DEFECTIVE)

    B

    GO TO DTC CHART Click here