PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

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

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

Diagnosis condition:


  • Engine switch on (IG) and 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 (brake actuator assembly) differ for 0.3 seconds or more continuously.

  • Lighting system

  • Skid control ECU (Brake actuator assembly)

  • Semiconductor power integration ECU (Stop light relay)

  • Wire harness or connector

WIRING DIAGRAM

A01RAEYE06

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

  • 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.

    Click here

PROCEDURE


  1. INSPECT ENGINE START


    1. Depress the brake pedal, push the engine switch and check that the engine starts.

      OK
      The engine starts.
      Result
      Result Proceed to
      OK A
      NG (for 8AR-FTS) B
      NG (for 2GR-FKS) C

    B

    GO TO SFI SYSTEM Click here

    C

    GO TO SFI SYSTEM w/ Canister Pump Module: Click here w/o Canister Pump Module: Click here

    A

  2. 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.
      Result
      Proceed to
      OK
      NG

    NG

    GO TO LIGHTING SYSTEM Click here

    OK

  3. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU


    1. Turn the engine switch off.

    2. Inspect the semiconductor power integration ECU.

      Click here

      OK
      The semiconductor power integration ECU is normal.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (STPO TERMINAL VOLTAGE)


    1. Turn the engine switch off.

    2. A01R96QC03
      *a

      Front view of wire harness connector

      (to Skid control ECU (brake actuator assembly))

      Disconnect the A41 skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A41-32 (STPO) - Body ground Always 11 to 14 V

    4. Connect the A41 skid control ECU (brake actuator assembly) connector.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU) Click here

    OK

  5. 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


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

      Chassis > ABS/VSC/TRC/EPB > Active Test
      Active Test Display
      Stop Light Relay
      Data List Display
      Stop Light Relay Output

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

      Click here


      Chassis > ABS/VSC/TRC/EPB > Data List
      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 (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU) Click here

    A

  6. INSPECT SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)


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

      Click here


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

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

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

      Tech Tips

      Do not disconnect the semiconductor power integration ECU connector.

      Standard Voltage
      Tester Connection Condition Specified Condition
      1D-3 (ACC) - Body ground

      Engine switch on (IG)

      (Active test OFF)

      		 11 to 14 V

      Engine switch on (IG)

      (Active test ON)

      		 Below 1.5 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) Click here

    OK

  7. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU


    1. Replace the semiconductor power integration ECU.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  8. CHECK DTC OUTPUT (VEHICLE STABILITY CONTROL SYSTEM)


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Clear DTCs

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

      Click here


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

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

    3. Check for DTCs.

      Click here


      Chassis > ABS/VSC/TRC/EPB > Trouble Codes
      Result
      Result Proceed to
      DTC C1380 is not output A
      DTC C1380 is output B

    A

    END

    B

    GO TO DTC CHART (C1380) Click here

  9. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU


    1. Replace the semiconductor power integration ECU.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  10. REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)


    1. Replace the skid control ECU (brake actuator assembly).

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  11. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU)


    1. Turn the engine switch off.

    2. Remove the semiconductor power integration ECU.

    3. A01R96QC04
      *a

      Front view of wire harness connector

      (to Skid control ECU (brake actuator assembly))

      Disconnect the A41 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
      1F-9 (OUT) - A41-37 (STP2) Always Below 1 Ω

    5. Connect the A41 skid control ECU (brake actuator assembly) connector.

    6. Install the semiconductor power integration ECU.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  12. REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)


    1. Replace the skid control ECU (brake actuator assembly).

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  14. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - SKID CONTROL ECU)


    1. Turn the engine switch off.

    2. Remove the semiconductor power integration ECU.

    3. Disconnect the A41 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
      1D-3 (ACC) - A41-32 (STPO) Always Below 1 Ω
      1D-3 (ACC) or A41-32 (STPO) - Body ground Always 10 kΩ or higher

    5. Connect the A41 skid control ECU (brake actuator assembly) connector.

    6. Install the semiconductor power integration ECU.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  15. REPLACE SEMICONDUCTOR POWER INTEGRATION ECU


    1. Replace the semiconductor power integration ECU.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here

  16. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 8 Click here