PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:C1A4B

DTC Code DTC Name
C1A4B Stop Light Relay Circuit

DESCRIPTION

The skid control ECU assembly sends a stop light operation signal to the semiconductor power integration ECU. When the skid control ECU assembly 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 power 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 power 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

  • Skid control ECU assembly

  • Semiconductor power integration ECU

  • Harness or connector

WIRING DIAGRAM

A01WYQTE07

INSPECTION PROCEDURE

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. INSPECT HYBRID CONTROL SYSTEM START


    1. Depress the brake pedal, push the power switch and check that the hybrid control system starts.

      OK
      The hybrid control system starts.
      Result
      Proceed to
      OK
      NG

    NG

    GO TO HYBRID CONTROL SYSTEM Click here

    OK

  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 for Triple Beam Headlight: Click here
    GO TO LIGHTING SYSTEM for Single Beam Headlight: Click here

    OK

  3. INSPECT SEMICONDUCTOR POWER INTEGRATION ECU


    1. Turn the power switch off.

    2. Check 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 TERMINAL VOLTAGE (STPO TERMINAL)


    1. Turn the power switch off.

    2. A01OALCC38
      *a

      Front view of wire harness connector

      (to Skid Control ECU Assembly)

      Disconnect the A23 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
      A23-31 (STPO) - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


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


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Switches stop light on/off ON or OFF Stop lights come on

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

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


      Chassis > ABS/VSC/TRC > 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

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Stop Light Relay 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 (SKID CONTROL ECU ASSEMBLY - SEMICONDUCTOR POWER INTEGRATION ECU) Click here

    A

  6. INSPECT SKID CONTROL ECU ASSEMBLY


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


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Stop Light Relay Stop lights ON or OFF Stop lights come on

      Chassis > ABS/VSC/TRC > 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 engine room junction block assembly connector.

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

      Power switch on (IG)

      (Active test is OFF)

      		 11 to 14 V

      Power switch on (IG)

      (Active test is ON)

      		 Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU (STOP LIGHT RELAY) Click here

    NG

    REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here

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


    1. Turn the power switch off.

    2. Disconnect the A22 skid control ECU assembly connector.

    3. Remove the semiconductor power integration ECU.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-24 (STP2) - 1F-9 (OUT) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Turn the power switch off.

    2. Disconnect the A23 skid control ECU assembly connector.

    3. Remove the semiconductor power integration ECU.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A23-31 (STPO) - 1D-3 (ACC) Always Below 1 Ω
      A23-31 (STPO) or 1D-3 (ACC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU (STOP LIGHT RELAY) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR