VEHICLE STABILITY CONTROL SYSTEM(for Hydraulic Brake Booster), Diagnostic DTC:C1379

DTC Code DTC Name
C1379 Downhill Assist Control Switch Malfunction (Test Mode DTC)

DESCRIPTION

w/o Combination Switch (w/ Downhill Assist Control):

DTC C1379 is cleared when the downhill assist control switch sends a downhill assist control operation signal or when test mode ends.

w/ Combination Switch:

DTC C1379 is cleared when the crawl on/off switch (combination switch assembly) and crawl speed selector (combination switch assembly) send a crawl control operation signal or when test mode ends.

DTC Code DTC Detection Condition Trouble Area
C1379 Stored only during test mode.

  • Downhill assist control switch (w/o Combination Switch (w/ Downhill Assist Control))

  • Crawl on/off switch (Combination switch assembly) (w/ Crawl Control)

  • Crawl speed selector (Combination switch assembly) (w/ Crawl Control)

  • Harness or connector

  • Skid control ECU (Master cylinder solenoid)

WIRING DIAGRAM

B001D36E15
B001D36E16

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU (master cylinder solenoid), perform calibration Click here.

PROCEDURE


  1. READ VALUE USING GTS (DOWNHILL ASSIST CONTROL SW)


    1. Turn the ignition switch off.

    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. Check the Data List for proper functioning of the downhill assist control switch.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Downhill Assist Control SW Downhill assist control switch / ON or OFF

      ON: Downhill assist control on

      OFF: Downhill assist control off

      		 -
      OK
      The GTS displays ON or OFF according to downhill assist control switch operation.
      Result
      Result Proceed to
      OK A
      NG (w/o Crawl Control) B
      NG (w/ Crawl Control) C

    B

    INSPECT DOWNHILL ASSIST CONTROL SWITCH Click here

    C

    INSPECT COMBINATION SWITCH ASSEMBLY Click here

    A

  2. CHECK TEST MODE DTC


    1. Perform the downhill assist control switch check in the Test Mode Procedure Click here.

      OK
      Test mode DTC C1379 is cleared.
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE MASTER CYLINDER SOLENOID Click here

    C

    REPLACE MASTER CYLINDER SOLENOID Click here

  3. INSPECT DOWNHILL ASSIST CONTROL SWITCH


    1. Remove the downhill assist control switch Click here.

    2. B001FMDE02
      Text in Illustration
      *a

      Component without harness connected

      (Downhill Assist Control Switch)

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      2 - 5 Not pushed in 10 kΩ or higher
      Pushed in Below 1 Ω

    NG

    REPLACE DOWNHILL ASSIST CONTROL SWITCH Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (MASTER CYLINDER SOLENOID - DOWNHILL ASSIST CONTROL SWITCH)


    1. Disconnect the A7 skid control ECU (master cylinder solenoid) connector.

    2. Disconnect the G232 downhill assist control switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A7-28 (HZRI) - G232-5 (+B2) Always Below 1 Ω
      A7-28 (HZRI) or G232-5 (+B2) - Body ground Always 10 kΩ or higher
      G232-2 (E) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE MASTER CYLINDER SOLENOID Click here

    B

    REPLACE MASTER CYLINDER SOLENOID Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  5. INSPECT COMBINATION SWITCH ASSEMBLY


    1. Remove the combination switch assembly Click here.

    2. Inspect the combination switch assembly Click here.


    NG

    REPLACE COMBINATION SWITCH ASSEMBLY Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (COMBINATION SWITCH ASSEMBLY - MASTER CYLINDER SOLENOID)


    1. Disconnect the G156 downhill assist control switch (combination switch assembly) connector.

    2. Disconnect the A7 skid control ECU (master cylinder solenoid) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A7-28 (HZRI) - G306-5 (+B2) Always Below 1 Ω
      A7-28 (HZRI) or G306-5 (+B2) - Body ground Always 10 kΩ or higher
      G306-2 (E) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    A

    REPLACE MASTER CYLINDER SOLENOID Click here

    B

    REPLACE MASTER CYLINDER SOLENOID Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR