DYNAMIC RADAR CRUISE CONTROL SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The brake actuator assembly outputs a stop light operation signal to the stop light control relay. When the brake actuator assembly detects a malfunction in the circuit related to the stop light, it informs the driving support ECU via CAN communication and stores DTC C1A4B.

DTC Code DTC Detection Condition Trouble Area
C1A4B When the engine switch on (IG), the IG1 terminal voltage is between 11 and 14 V, there is no input signal to terminal STP2 of the brake actuator assembly for 0.3 seconds or more when the stop light illumination output (STPO) of the brake actuator assembly is ON, or the input signals to terminals STP and STP2 of the brake actuator assembly are different for 0.3 seconds or more when the stop light illumination output (STPO) of the brake actuator assembly is OFF.

  • Light system

  • Vehicle stability control system

  • Harness or connector

  • No. 2 integration relay

  • Driving support ECU

WIRING DIAGRAM

A01FEYPE03

INSPECTION PROCEDURE

Note


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

  • When this DTC is output, a malfunction in the lighting system is suspected. Check if the lighting system is functioning normally 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
      Condition Illumination Condition
      Brake pedal depressed ON
      Brake pedal released OFF

    NG

    GO TO LIGHTING SYSTEM Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY POWER SOURCE TERMINAL)


    1. A01FIIME01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 Integration Relay)

      Turn the engine switch off.

    2. Disconnect the No. 2 integration relay connectors.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2B-7 (BATT) - Body ground Always 11 to 14 V

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2A-22 (GNDA) - Body ground Always Below 1 Ω
      2B-10 (GNDB) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (STP TERMINAL)


    1. Turn the engine switch off.

    2. A01FH1RE04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly)

      Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the brake actuator assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A13-2 (STP) - Body ground Brake pedal depressed 11 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (BATTERY - NO. 2 INTEGRATION RELAY)


    1. Turn the engine switch off.

    2. A01FIPDE21
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 Integration Relay)

      Disconnect the No. 2 integration relay connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2A-11 (STPO) - Body ground Brake pedal depressed 11 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. PERFORM ACTIVE TEST USING GTS (STOP LIGHT RELAY)


    1. Turn the engine switch off.

    2. Connect the GTS to the DLC3.

    3. Start the engine.

    4. Turn the GTS on.

    5. Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test. Click here

      ABS/VSC/TRAC
      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay No. 2 integration relay ON / OFF Observe the stop light (the stop lights do not come on for 2 to 5 seconds).

    6. While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List. Click here

      ABS/VSC/TRAC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light Relay Output No. 2 integration relay output / ON or OFF

      ON: Relay output ON

      OFF: Relay output OFF

      		 -
      Result
      Result Proceed to
      When Active Test performed, Data List item changes between ON and OFF, but stop lights do not turn on A
      When Active Test performed, Data List item changes between ON and OFF and stop lights turn on and off B

    B

    CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BRAKE ACTUATOR ASSEMBLY) Click here

    A

  6. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BRAKE ACTUATOR ASSEMBLY)


    1. Turn the engine switch off.

    2. Disconnect the 2A No. 2 integration relay connector.

    3. Disconnect the A13 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2A-7 (ACC) - A13-31 (STPO) Always Below 1 Ω
      2A-7 (ACC) - Body ground Always 10 kΩ or higher
      2A-18 (ESS) - A13-8 (EXO)* Always Below 1 Ω
      2A-18 (ESS) - Body ground* Always 10 kΩ or higher

      • *: w/ Emergency Brake Signal


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY - BRAKE ACTUATOR ASSEMBLY)


    1. Turn the engine switch off.

    2. Disconnect the 2A No. 2 integration relay connector.

    3. Disconnect the A13 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2A-3 (STOP) - A13-22 (STP2) Always Below 1 Ω
      2A-3 (STOP) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (STP2 TERMINAL)


    1. Turn the engine switch off.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. A01FH1RE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly)

      Disconnect the brake actuator assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A13-22 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      Brake pedal released Below 1.5 V

    NG

    REPLACE NO. 2 INTEGRATION RELAY Click here

    OK

  9. CHECK FOR DTC


    1. Turn the engine switch off and wait for at least 2 minutes.

    2. Clear the DTCs Click here.

    3. Make sure that the DTC detection conditions are met.

      Tech Tips

      If the detection conditions are not met, the system cannot detect the malfunction.


      • Using the GTS, perform the Active Test "Stop Light Relay" with the engine switch on (IG).

    4. Check for DTCs Click here.

      Note

      When replacing the driving support ECU, always replace it with a new one and be sure to perform initialization Click here. If an ECU which was installed to another vehicle is used, the information stored in the ECU will not match the information from the vehicle, and as a result, a DTC may be stored.

      OK
      DTC C1A4B is not output.

    NG

    REPLACE DRIVING SUPPORT ECU Click here

    OK

    END