Toyota 4Runner: Brake Warning Light Remains ON

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

DESCRIPTION

The BRAKE warning light comes on when brake fluid is insufficient, the parking brake is applied or the EBD is defective.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	CHECK FOR DTC

(a) Check for DTCs (See page ).

Result

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

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

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.	READ VALUE USING TECHSTREAM (PARKING BRAKE SW)

(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
Parking Brake SW	Parking brake switch/ ON or OFF	ON: Parking brake applied OFF: Parking brake released	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Parking Brake SW

Parking brake switch/ ON or OFF

ON: Parking brake applied

OFF: Parking brake released

(f) Using the Techstream, check the input of the switch operation when the parking brake pedal is operated.

OK:

When the parking brake is operated, the display changes as shown above.

GO TO STEP 5

4.	READ VALUE USING TECHSTREAM (BRAKE WARNING LIGHT)

(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
Brake Warning Light	Brake warning light/ ON or OFF	ON: Warning light on OFF: Warning light off	-

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Brake Warning Light

Brake warning light/ ON or OFF

ON: Warning light on

OFF: Warning light off

(f) When performing the Brake Warning Light Active Test, check Brake Warning Light in the Data List (See page ).

ABS/VSC/TRAC

Tester Display	Test Part	Control Range	Diagnostic Note
Brake Warning Light	Brake warning light	Warning light ON/OFF	Observe the combination meter.

Result

Result		Proceed to
Data List Display	Data List Display when Performing Active Test ON/OFF Operation	Proceed to
ON	Does not change between ON and OFF	A
ON	Changes between ON and OFF	B
OFF	Does not change between ON and OFF	A
OFF	Changes between ON and OFF	B

REPLACE MASTER CYLINDER SOLENOID

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

5.	INSPECT PARKING BRAKE SWITCH

(a) Disconnect the A2 parking brake switch connector.

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

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

1 - Body ground

Parking brake applied

(Switch pin not pushed in)

Below 1 Ω

Parking brake released

(Switch pin pushed in)

10 kΩ or higher

Text in Illustration

*a	Component without harness connected (Parking Brake Switch)

REPLACE PARKING BRAKE SWITCH ASSEMBLY

6.	CHECK HARNESS AND CONNECTOR (PARKING BRAKE SWITCH - MAIN BODY ECU [DRIVER SIDE JUNCTION BLOCK])

(a) Disconnect the A2 parking brake switch connector.

(b) Disconnect the 2D main body ECU (driver side junction block assembly) connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A2-1 - 2D-17 (PKB)	Always	Below 1 Ω
A2-1 - Body ground	Always	10 kΩ or higher

REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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