Dtc C1379 Downhill Assist Control Switch Malfunction (Test Mode Dtc)


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CONFIRM VEHICLE SPECIFICATIONS

READ VALUE USING GTS (DOWNHILL ASSIST CONTROL SW)

CHECK TEST MODE DTC

INSPECT DOWNHILL ASSIST CONTROL SWITCH

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

CHECK CAN BUS

READ VALUE USING GTS (CRAWL CONTROL MAIN SWITCH AND DIAL SWITCH SIGNAL)

CHECK TEST MODE DTC

CHECK HARNESS AND CONNECTOR (CENTER CLUSTER MODULE SWITCH - DRIVING SUPPORT SWITCH CONTROL ECU)

INSPECT CENTER CLUSTER MODULE SWITCH

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


DESCRIPTION

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/ Crawl Control:
DTC C1379 is cleared when the crawl on/off switch (center cluster module switch) and crawl speed selector (center cluster module switch) send a crawl control operation signal or when test mode ends.

DTC Code
DTC Detection Condition
Trouble Area
C1379
Stored only during test mode.
  1. Downhill assist control switch (w/ Downhill Assist Control)
  2. Crawl on/off switch (Center cluster module switch) (w/ Crawl Control)
  3. Crawl speed selector (Center cluster module switch) (w/ Crawl Control)
  4. Harness or connector
  5. Skid control ECU (Master cylinder solenoid)

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1379 Downhill Assist Control Switch Malfunction (Test Mode Dtc)


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1379 Downhill Assist Control Switch Malfunction (Test Mode Dtc)


INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU (master cylinder solenoid), perform calibration (LandCruiser RM00000452J00ZX.html).
1.CONFIRM VEHICLE SPECIFICATIONS

  1. Confirm the vehicle specifications.

    Result
    Result
    		Proceed to
    w/ Downhill Assist Control
    		A
    w/ Crawl Control
    		B


B
Go to step 6
A


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

  1. Turn the ignition switch off.

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

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

  1. 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.


NG
Go to step 4
OK


3.CHECK TEST MODE DTC

  1. Perform the downhill assist control switch check in the Test Mode Procedure (LandCruiser RM00000452K011X.html).

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


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)

4.INSPECT DOWNHILL ASSIST CONTROL SWITCH

  1. Remove the downhill assist control switch (LandCruiser RM000001PC0010X.html).



    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1379 Downhill Assist Control Switch Malfunction (Test Mode Dtc)

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 - 4
    		Not pushed in
    		10 kΩ or higher
    Pushed in
    		Below 1 Ω
    Text in Illustration
    *a
    		Component without harness connected
    (Downhill Assist Control Switch)


NG
REPLACE DOWNHILL ASSIST CONTROL SWITCH (LandCruiser RM000001PC0010X.html)
OK


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

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

  1. Disconnect the G158 downhill assist control switch connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A7-44 (HDCS) - G158-4
    		Always
    		Below 1 Ω
    A7-44 (HDCS) or G158-4 - Body ground
    		Always
    		10 kΩ or higher
    G158-1 - Body ground
    		Always
    		Below 1 Ω
    Result
    Result
    		Proceed to
    NG
    		A
    OK (for LHD)
    		B
    OK (for RHD)
    		C


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.CHECK CAN BUS

  1. Check that there are no problems with the CAN communication system (for LHD: LandCruiser RM000000WIB0ECX.html, for RHD: LandCruiser RM000000WIB0EEX.html).

    Result
    Result
    		Proceed to
    OK
    		A
    NG (for LHD)
    		B
    NG (for RHD)
    		C


B
GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (LandCruiser RM000001RSO0C5X.html)

C
GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) (LandCruiser RM000001RSO0BZX.html)
A


7.READ VALUE USING GTS (CRAWL CONTROL MAIN SWITCH AND DIAL SWITCH SIGNAL)

  1. Turn the ignition switch off.

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the GTS on.

  1. Enter the following menus: Body Electrical / D-SEAT SW / Data List.



  1. Check the Data List for proper functioning of the crawl on/off switch (center cluster module switch) and crawl speed selector (center cluster module switch).

    D-SEAT SW
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Crawl Control Main Switch
    		Crawl on/off switch/ ON or OFF
    		ON: Switch on
    OFF: Switch off
    		-
    Dial Switch Signal 1
    		Crawl speed selector/Multi-terrain select road mode selector signal 1/ ON or OFF
    		Switches between ON and OFF according to the ON/OFF Combination Chart below.
    		-
    Dial Switch Signal 2
    		Crawl speed selector/Multi-terrain select road mode selector signal 2/ ON or OFF
    		-
    Dial Switch Signal 3
    		Crawl speed selector/Multi-terrain select road mode selector signal 3/ ON or OFF
    		-


      Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Brake Control Dynamic Control Systems.Anti-Lock Brake System. Dtc C1379 Downhill Assist Control Switch Malfunction (Test Mode Dtc)

    1. Operate the crawl speed selector/multi-terrain select road mode selector and check that "Dial Switch Signal 1", "Dial Switch Signal 2" and "Dial Switch Signal 3" in the Data List display ON and OFF according to the chart shown below.

      Text in Illustration
      *1
      		Center Cluster Module Switch
      *2
      		Crawl On/Off Switch
      *3
      		Multi-terrain Select Switch
      *4
      		Crawl Speed Selector/Multi-terrain Select Road Mode Selector
      *a
      		Low/MUD & SAND
      *b
      		Medium-low/LOOSE ROCK
      *c
      		Medium/MOGUL
      *d
      		Medium-high/ROCK & DIRT
      *e
      		High/ROCK

      ON/OFF Combination Chart for "Dial Switch Signal 1", "Dial Switch Signal 2" and "Dial Switch Signal 3"
      Crawl Speed Selector Position/Multi-terrain Select Road Mode Selector Position
      		Low/MUD & SAND
      		Medium-low/LOOSE ROCK
      		Medium/MOGUL
      		Medium-high/ROCK & DIRT
      		High/ROCK
      Data List Display
      		Dial Switch Signal 1
      		ON
      		ON
      		OFF
      		OFF
      		OFF
      Dial Switch Signal 2
      		ON
      		OFF
      		OFF
      		OFF
      		ON
      Dial Switch Signal 3
      		OFF
      		OFF
      		OFF
      		ON
      		ON
      OK:
      The GTS display changes according to crawl on/off switch (center cluster module switch) and crawl speed selector (center cluster module switch) operation.


NG
Go to step 9
OK


8.CHECK TEST MODE DTC

  1. Perform the crawl on/off switch (center cluster module switch) and crawl speed selector (center cluster module switch) check in the Test Mode Procedure (LandCruiser RM00000452K011X.html).

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


B
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02DX.html)

C
REPLACE MASTER CYLINDER SOLENOID (LandCruiser RM00000171U02EX.html)
A

USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)

9.CHECK HARNESS AND CONNECTOR (CENTER CLUSTER MODULE SWITCH - DRIVING SUPPORT SWITCH CONTROL ECU)

  1. Disconnect the G156 center cluster module switch connector.

  1. Disconnect the G162 driving support switch control ECU connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    G162-6 (CRWL) - G156-21 (FRB)
    		Always
    		Below 1 Ω
    G162-4 (MOD1) - G156-17 (ECU)
    		Always
    		Below 1 Ω
    G162-11 (MOD3) - G156-19 (DN)
    		Always
    		Below 1 Ω
    G162-2 (MOD2) - G156-18 (UP)
    		Always
    		Below 1 Ω
    G156-24 (E) - Body ground
    		Always
    		Below 1 Ω
    G162-6 (CRWL) or G156-21 (FRB) - Body ground
    		Always
    		10 kΩ or higher
    G162-4 (MOD1) or G156-17 (ECU) - Body ground
    		Always
    		10 kΩ or higher
    G162-11 (MOD3) or G156-19 (DN) - Body ground
    		Always
    		10 kΩ or higher
    G162-2 (MOD2) or G156-18 (UP) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


10.INSPECT CENTER CLUSTER MODULE SWITCH

  1. Remove the center cluster module switch (LandCruiser RM000003C4A01HX.html).

  1. Inspect the crawl on/off switch (center cluster module switch) and crawl speed selector (center cluster module switch) (LandCruiser RM000003C4B017X.html).



NG
REPLACE CENTER CLUSTER MODULE SWITCH (LandCruiser RM000003C4A01HX.html)
OK

REPLACE DRIVING SUPPORT SWITCH CONTROL ECU (LandCruiser RM00000466X024X.html)