Toyota 4Runner: TRAC OFF Indicator Light Remains ON

Toyota 4Runner Service Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / TRAC OFF Indicator Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter via the CAN communication system. Pressing the VSC OFF switch turns off traction control and pressing and holding this switch turns off traction control and VSC. If TRAC control turns off, the TRAC OFF indicator light comes on.

If there is a malfunction in the engine control system, the TRAC and A-TRAC system will turn off and the TRAC OFF indicator will turn on.

When the temperature inside the hydraulic brake booster becomes too high, the TRAC OFF indicator light turns on and traction control is stopped until the temperature decreases.

for 4WD:

When the transfer is in L4, VSC is prohibited and the VSC OFF indicator and TRAC OFF indicator lights turn on.
w/ Rear Differential Lock:
When the rear differential is locked, VSC is prohibited and the VSC OFF indicator and TRAC OFF indicator lights turn on. At this time, ABS is also prohibited and the ABS warning light turns on.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

As there may be malfunctions in the transfer system related to when the transfer operates in L4, check the transfer system first (for Part-time 4WD: See page , for Full-time 4WD: See
page ).

PROCEDURE

1.	CHECK DTC (ENGINE CONTROL SYSTEM)

(a) Check if any DTC is recorded for the engine control system (See page ).

Result

Result	Proceed to
DTC is not output	A
DTC is output	B

GO TO ENGINE CONTROL SYSTEM (DIAGNOSTIC TROUBLE CODE CHART)

2.	CHECK CAN COMMUNICATION LINE

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Select CAN Bus Check from the System Selection Menu screen and follow the prompts on the screen to inspect the CAN bus (See page ).

OK:

CAN Bus Check indicates no malfunctions in CAN communication.

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

3.	CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU CSW CIRCUIT)

(a) Disconnect the A6 skid control ECU connector.

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
A6-9 (CSW) - Body ground	VSC OFF switch not pushed in	10 kΩ or higher
A6-9 (CSW) - Body ground	VSC OFF switch pushed in	Below 1 Ω

GO TO STEP 6

4.	CHECK TERMINAL VOLTAGE (EXI3)

(a) Disconnect the A6 skid control ECU connector.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A6-40 (EXI3) - Body ground

Ignition switch ON

w/ Rear Differential Lock: Rear differential free

11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU)

Result

Result	Proceed to
OK	A
NG (for 4WD)	B
NG (for 2WD)	C

GO TO STEP 8

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	READ VALUE USING TECHSTREAM (TRAC/VSC OFF MODE)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

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

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
TRAC/VSC Off Mode	TRAC/VSC off mode/ Normal, TRC OFF or VSC OFF	Normal: Normal mode TRC OFF: TRAC OFF mode VSC OFF: VSC OFF mode	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

TRAC/VSC Off Mode

TRAC/VSC off mode/ Normal, TRC OFF or VSC OFF

Normal: Normal mode

TRC OFF: TRAC OFF mode

VSC OFF: VSC OFF mode

(f) Check that the mode display changes according to VSC OFF switch operation.

OK:

Display changes according to switch operation.

GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

REPLACE MASTER CYLINDER SOLENOID

6.	INSPECT VSC OFF SWITCH

(a) Remove the VSC OFF switch (See page ).

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
6 (OFF) - 3 (VSC)	Switch is not pushed	10 kΩ or higher
6 (OFF) - 3 (VSC)	Switch is pushed	Below 1 Ω

Text in Illustration

*a	Component without harness connected (VSC OFF Switch)

REPLACE VSC OFF SWITCH

7.	CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - VSC OFF SWITCH)

(a) Disconnect the A6 skid control ECU connector.

(b) Disconnect the U6 VSC OFF switch connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A6-9 (CSW) - U6-6 (OFF)	Always	Below 1 Ω
A6-9 (CSW) - Body ground	Always	10 kΩ or higher
U6-3 (VSC) - Body ground	Always	Below 1 Ω

REPLACE MASTER CYLINDER SOLENOID

REPAIR OR REPLACE HARNESS OR CONNECTOR

8.	CHECK TERMINAL VOLTAGE (EXI3)

(a) Disconnect the A6 skid control ECU connector.

(b) Disconnect the F47 four wheel drive control ECU connector.

Disconnect the D3 rear differential lock detection switch connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A6-40 (EXI3) - Body ground	Always	10 kΩ or higher

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU)

Result

Result	Proceed to
OK (w/o Rear Differential Lock)	A
OK (w/ Rear Differential Lock)	B
NG	C

GO TO STEP 10

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CHECK TERMINAL VOLTAGE (EXI3)

(a) Disconnect the A6 skid control ECU connector.

(b) Connect the F47 four wheel drive control ECU connector.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A6-40 (EXI3) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU)

REPLACE MASTER CYLINDER SOLENOID

REPLACE FOUR WHEEL DRIVE CONTROL ECU

10.	INSPECT REAR DIFFERENTIAL LOCK DETECTION SWITCH (REAR DIFFERENTIAL LOCK POSITION SWITCH)

(a) Remove the rear differential lock detection switch (See page ).

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
2 (+B) - 1 (GND)	Pushed in	Below 1 Ω
2 (+B) - 1 (GND)	Not pushed in	10 kΩ or higher

Text in Illustration

*a	Component without harness connected (Differential Lock Detection Switch (Differential Lock Position Switch))

REPLACE REAR DIFFERENTIAL LOCK DETECTION SWITCH (REAR DIFFERENTIAL LOCK POSITION SWITCH)

11.	CHECK TERMINAL VOLTAGE (EXI3)

(a) Disconnect the A6 skid control ECU connector.

(b) Connect the F47 four wheel drive control ECU connector.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A6-40 (EXI3) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Skid Control ECU)

REPLACE MASTER CYLINDER SOLENOID

REPLACE FOUR WHEEL DRIVE CONTROL ECU

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