VEHICLE STABILITY CONTROL SYSTEM Downhill Assist Control Indicator Light does not Come ON

DTC Code DTC Name
Downhill Assist Control Indicator Light does not Come ON

DESCRIPTION

Even if the downhill assist control switch is pressed, the downhill assist control indicator light blinks and downhill assist control does not activate under the following conditions:

  • Gear position is not R.

  • The brake system is malfunctioning.

  • The vehicle speed is 25 km/h (15 mph) or more.

WIRING DIAGRAM

C350466E01

CAUTION / NOTICE / HINT

Note:

When replacing the skid control ECU (brake actuator assembly), perform zero point calibration.

Click here

PROCEDURE

  1. CHECK CAN COMMUNICATION SYSTEM

    1. Check if CAN communication system DTCs are output.

      for LHD with Central Gateway ECU:Click here

      for RHD with Central Gateway ECU:Click here

      for LHD without Central Gateway ECU:Click here

      for RHD without Central Gateway ECU:Click here

    Result

    Proceed to

    DTC is not output

    DTC is output (for LHD with Central Gateway ECU)

    DTC is output (for RHD with Central Gateway ECU)

    DTC is output (for LHD without Central Gateway ECU)

    DTC is output (for RHD without Central Gateway ECU)
    DTC is output (for LHD with Central Gateway ECU)

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    DTC is output (for RHD with Central Gateway ECU)

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    DTC is output (for LHD without Central Gateway ECU)

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    DTC is output (for RHD without Central Gateway ECU)

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    DTC is not output

  2. CHECK HARNESS AND CONNECTOR (HDCS TERMINAL)

    1. Turn the ignition switch off.

    2. Disconnect the A80 skid control ECU (brake actuator assembly) connector.

    3. C342353C32

      *a

      Front view of wire harness connector

      (to Skid Control ECU [Brake Actuator Assembly])

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

      Standard Resistance

      Tester Connection

      Switch Condition

      Specified Condition

      A80-27 (HDCS) - Body ground

      Downhill assist control switch is pushed

      Below 1 Ω

      A80-27 (HDCS) - Body ground

      Downhill assist control switch is not pushed

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    INSPECT DOWNHILL ASSIST CONTROL SWITCHClick here

    OK

  3. PERFORM ACTIVE TEST USING GTS (DOWNHILL ASSIST CONTROL LIGHT)

    1. Reconnect the A80 skid control ECU (brake actuator assembly) connector.

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

    5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

    6. According to the display on the GTS, perform the Active Test.

    7. When performing the ABS Warning Light Active Test, check Downhill assist control indicator light in the Data List.

    Chassis > ABS/VSC/TRC > Active Test

    Tester Display

    Measurement Item

    Control Range

    Diagnostic Note

    Downhill Assist Control Light

    Downhill assist control indicator light

    Indicator light OFF/ON

    Observe combination meter

    Vehicle condition: Vehicle stopped

    Chassis > ABS/VSC/TRC > Data List

    Tester Display

    Measurement Item

    Range

    Normal Condition

    Diagnostic Note

    Downhill Assist Control Light

    Downhill assist control indicator light

    ON or OFF

    OFF: Downhill assist control indicator light off

    ON: Downhill assist control indicator light on

    w/ Downhill Assist Control:

    The item is displayed on the GTS but not used.

    OFF: Always

    Chassis > ABS/VSC/TRC > Active Test

    Active Test Display

    Downhill Assist Control Light

    Data List Display

    Downhill Assist Control Light

    Result

    Result

    Proceed to

    Downhill assist control indicator light in the Data List does not change using the Active Test

    A

    Downhill assist control indicator light in the Data List turns ON/OFF using the Active Test

    B
    A

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

    B

  4. INSPECT COMBINATION METER ASSEMBLY

    1. Turn the ignition switch off.

    2. Perform Active Test of the combination meter assembly using the GTS.

    3. Check the combination meter assembly.

    Body Electrical > Combination Meter > Active Test

    Tester Display

    Indicat. Downhill Assist Control

    OK

    The Downhill assist control indicator light turns on or off in accordance with the GTS.

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY

    Click here

    NG

    INSPECT METER / GAUGE SYSTEM

    Click here

  5. INSPECT DOWNHILL ASSIST CONTROL SWITCH

    1. Turn the ignition switch off.

    2. Remove the downhill assist control switch.

      Click here

    3. Inspect the downhill assist control switch.

      Click here

    Result

    Result

    OK

    NG
    NG

    REPLACE DOWNHILL ASSIST CONTROL SWITCH

    Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - DOWNHILL ASSIST CONTROL SWITCH)

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A80-27 (HDCS) - G29-4

      Always

      Below 1 Ω

      A80-27 (HDCS) or G29-4 - Body ground

      Always

      10 kΩ or higher

      G29-1 - Body ground

      Always

      Below 1 Ω

      Result

      Result

      OK

      NG
    OK

    USE SIMULATION METHOD TO CHECK

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR