PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The brake actuator assembly (skid control ECU) sends a stop light operation signal to the semiconductor PWR integration ECU. When the brake actuator assembly (skid control ECU) detects a malfunction in the stop light circuit, the driving support ECU assembly stores DTC C1A4B.

DTC No. Detection Item DTC Detection Condition Trouble Area
C1A4B Stop Light Relay Circuit

Either of the following conditions is met:


  • When the engine switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is output, the signal is not received at terminal STP2 for 3 seconds or more.

  • When the engine switch is on (IG), the IG1 terminal voltage is between 11 and 14 V and the stop light illumination output signal (STPO) is not output, the signals received at terminals STP and STP2 are different for 3 seconds or more.

  • Lighting system

  • Vehicle stability control system

  • Harness or connector

  • Semiconductor PWR integration ECU

  • Driving support ECU assembly

WIRING DIAGRAM

A01VMQBC01

CAUTION / NOTICE / HINT

Note


  • Inspect the fuses for circuits related to this system before performing the following 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
      Result
      Proceed to
      OK
      NG

    NG

    GO TO LIGHTING SYSTEM Click here

    OK

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF SEMICONDUCTOR PWR INTEGRATION ECU)


    1. Turn the engine switch off.

    2. A01VN0JC10
      *a

      Front view of wire harness connector

      (to Semiconductor PWR Integration ECU)

      Disconnect the 2B semiconductor PWR integration ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2B-1 (BATT) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BODY GROUND)


    1. Turn the engine switch off.

    2. Disconnect the 2D and 2G semiconductor PWR integration ECU connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2D-14 - Body ground Always Below 1 Ω
      2G-5 - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK TERMINAL VOLTAGE (STP TERMINAL)


    1. Turn the engine switch off.

    2. A01VNNVC71
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

      Disconnect the A15 brake actuator assembly (skid control ECU) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A15-2 (STP) - Body ground Brake pedal depressed 11 to 14 V
      A15-2 (STP) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK TERMINAL VOLTAGE (STP TERMINAL)


    1. Turn the engine switch off.

    2. B0066UHC12
      *a

      Front view of wire harness connector

      (to Semiconductor PWR Integration ECU)

      Disconnect the 2D semiconductor PWR integration ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      2D-10 (STP) - Body ground Brake pedal depressed 11 to 14 V
      2D-10 (STP) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.

    2. Perform "Active Test" according to the display on the GTS.


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop light control relay (STOP LP) ON or OFF Stop lights come on

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      Stop Light Relay

    3. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

    4. Check the stop light switch assembly (stop light control relay) operation using the Data List and stop light operation by performing an Active Test.


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light Relay Output Stop light control relay (STOP LP) output ON or OFF

      ON: Relay output on (Stop light on)

      OFF: Relay output off (Stop light off)

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Stop Light Relay Output
      Result
      Result Proceed to
      Data List item changes between ON and OFF, but stop lights do not turn on A
      Data List item changes between ON and OFF and stop lights turn on and off B

    B

    GO TO STEP 8 Click here

    A

  7. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) - SEMICONDUCTOR PWR INTEGRATION ECU)


    1. Turn the engine switch off.

    2. Disconnect the A15 brake actuator assembly (skid control ECU) connector.

    3. Disconnect the 2D semiconductor PWR integration ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-31 (STPO) - 2D-3 (ACC) Always Below 1 Ω
      A15-31 (STPO) or 2D-3 (ACC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) - SEMICONDUCTOR PWR INTEGRATION ECU)


    1. Turn the engine switch off.

    2. Disconnect the A15 brake actuator assembly (skid control ECU) connector.

    3. Disconnect the 2F semiconductor PWR integration ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A15-22 (STP2) - 2F-9 (OUT) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK TERMINAL VOLTAGE (STP2 TERMINAL)


    1. Turn the engine switch off.

    2. A01VNNVC93
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly (Skid Control ECU))

      Disconnect the A15 brake actuator assembly (skid control ECU) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A15-22 (STP2) - Body ground Brake pedal depressed 11 to 14 V
      A15-22 (STP2) - Body ground Brake pedal released Below 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SEMICONDUCTOR PWR INTEGRATION ECU Click here

    OK

  10. CHECK FOR DTCs (PRE-CRASH 2)


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

    2. Clear the DTCs.

      Click here


      Body Electrical > Pre-Crash 2 > Clear DTCs

    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


      Body Electrical > Pre-Crash 2 > Trouble Codes

      Note

      When replacing the driving support ECU assembly, always replace it with a new one. If a driving support ECU assembly which was installed to another vehicle is used, the information stored in the driving support ECU assembly will not match the information from the vehicle. As a result, a DTC may be stored.

      Result
      Result Proceed to
      DTC C1A4B is not output A
      DTC C1A4B is output B

    A

    END

    B

    REPLACE DRIVING SUPPORT ECU ASSEMBLY Click here