Toyota 4Runner manuals

Toyota 4Runner: Downhill Assist Control Switch Malfunction (Test Mode DTC) (C1379)

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 control switch sends a crawl control operation signal or when test mode ends.

DTC Code

DTC Detection Condition

Trouble Area

C1379

Stored only during test mode.

  • ECU-IG NO. 1 fuse (w/ Crawl Control)
  • ECU-B fuse (w/ Crawl Control)
  • Downhill assist control switch (w/ Downhill Assist Control)
  • Crawl control switch (w/ Crawl Control)
  • Harness or connector
  • Master cylinder solenoid (Skid control ECU)

WIRING DIAGRAM



CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the master cylinder solenoid, perform calibration (See page ).

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

CONFIRM VEHICLE SPECIFICATIONS

(a) 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 TECHSTREAM (DOWNHILL ASSIST CONTROL SW)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

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

ABS/VSC/TRAC

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 Techstream displays ON or OFF according to downhill assist control switch operation.


NG

GO TO STEP 4

OK

3.

CHECK TEST MODE DTC

(a) Perform the Downhill Assist Control Switch Check in the Test Mode Procedure (See page ).


OK:

Test mode DTC C1379 is cleared.


OK

USE SIMULATION METHOD TO CHECK


NG

REPLACE MASTER CYLINDER SOLENOID

4.

INSPECT DOWNHILL ASSIST CONTROL SWITCH



NG

REPLACE DOWNHILL ASSIST CONTROL SWITCH

OK

5.

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - DOWNHILL ASSIST CONTROL SWITCH/BODY GROUND)

(a) Disconnect the A6 skid control ECU connector.

(b) Disconnect the U4 downhill assist control switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A6-44 (HDCS) - U4-4 (+B2)

Always

Below 1 Ω

A6-44 (HDCS) - Body ground

Always

10 kΩ or higher

U4-1 (E) - Body ground

Always

Below 1 Ω


OK

REPLACE MASTER CYLINDER SOLENOID


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.

CHECK CAN BUS

(a) Check that there are no problems with the CAN communication system (See page ).



NG

GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

OK

7.

READ VALUE USING TECHSTREAM (CRAWL CONTROL MODE SELECT SWITCH)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Body Electrical / D-SEAT SW / Data List.

(f) Check the Data List for proper functioning of the crawl control mode select switch.

D-SEAT SW

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Crawl Control Main Switch

Crawl control switch (ON/OFF switch)/ ON or OFF

ON: Crawl control on

OFF: Crawl control off

-

OK:

The Techstream displays ON or OFF according to crawl switch operation.


NG

GO TO STEP 10

OK

8.

READ VALUE USING TECHSTREAM (CRAWL CONTROL SWITCH)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

(f) Check the Data List for proper functioning of the crawl control switch.

ABS/VSC/TRAC

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Crawl Control Switch

Crawl switch (mode select switch)/ LOW, MIDLOW, MID, MIDHIGH or HIGH

Actual crawl speed selector switch position

-

OK:

The Techstream displays LOW, MIDLOW, MID, MIDHIGH or HIGH according to crawl switch (mode selector switch) operation.


NG

GO TO STEP 11

OK

9.

CHECK TEST MODE DTC

(a) Perform the crawl switch check in the Test Mode Procedure (See page ).


OK:

Test mode DTC C1379 is cleared.


OK

USE SIMULATION METHOD TO CHECK


NG

REPLACE MASTER CYLINDER SOLENOID

10.

CHECK TERMINAL VOLTAGE AND RESISTANCE (IG, +B, GND)

(a) Disconnect the U1 drive monitor switch connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

U1-6 (+B) - Body ground

Always

11 to 14 V

U1-12 (IG) - Body ground

Ignition switch ON

11 to 14 V


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

Standard Resistance:

Tester Connection

Condition

Specified Condition

U1-7 (GND) - Body ground

Always

Below 1 Ω

Text in Illustration

*a

Front view of wire harness connector

(to Drive Monitor Switch)


OK

REPLACE DRIVE MONITOR SWITCH


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.

REPLACE DRIVE MONITOR SWITCH

(a) Replace the drive monitor switch (See page ).


NEXT

12.

CHECK TEST MODE DTC

(a) Perform the crawl switch check in the Test Mode Procedure (See page ).


OK:

Test mode DTC C1379 is cleared.


OK

END


NG

REPLACE MASTER CYLINDER SOLENOID

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