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 signal to the semiconductor PWR 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 vehicle speed is approximately 36 km/h (22 mph) or more, the cruise control switch (ON-OFF button) is on, 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 0.3 seconds or more.

  • When the vehicle speed is approximately 36 km/h (22 mph) or more, the cruise control switch (ON-OFF button) is on, 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 0.3 seconds or more.

  • Skid control ECU assembly

  • Semiconductor PWR integration ECU

  • Harness or connector

WIRING DIAGRAM

A01WYQTE08

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.

    for Triple Beam Headlight: Click here

    for Single Beam Headlight: Click here

PROCEDURE


  1. INSPECT SEMICONDUCTOR PWR INTEGRATION ECU


    1. Turn the engine 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

    INSPECT SEMICONDUCTOR PWR INTEGRATION ECU (RESULT OF SIGNAL READING CHECK) Click here

    OK

  2. CHECK TERMINAL VOLTAGE (STPO TERMINAL)


    1. Turn the power switch off.

    2. A01WXZ8C37
      *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

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


    1. Enter the following menus: Chassis / ABS/VSC/TRC / 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 Switches stop light on/off 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/TRC / Data List.

    4. Check the semiconductor power integration ECU (stop light 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 STPO terminal output condition ON or OFF

      ON: Output

      OFF: Not output

      		 -

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Stop Light Relay Output
      Result
      Result Proceed to
      Data List content and stop light operation are abnormal. A
      Data List content is normal but stop lights do not turn on or off. B

    B

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

    A

  4. INSPECT SKID CONTROL BUZZER ASSEMBLY


    1. Enter the following menus: Chassis / ABS/VSC/TRC / 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 Switches stop light on/off ON or OFF Stop lights come on

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

    3. 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
      1D-3 (ACC) - Body ground

      Power switch on (IG)

      (Active test is ON)

      		 Below 1.5 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE SEMICONDUCTOR PWR 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

  5. 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. Disconnect the 1F semiconductor power integration ECU connector.

    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

  6. 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. Disconnect the 1D semiconductor power integration ECU connector.

    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 PWR INTEGRATION ECU (STOP LIGHT RELAY) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR