Last Modified: 11-29-2007 1.6 J
Service Category: Brake Section: Brake Control/Dynamic Control System
Model Year: 2008 Model: Sequoia Doc ID: RM000001CGN017X
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DESCRIPTION (2008 Sequoia)

Brake Warning Light Remains ON

DESCRIPTION

If any of the following conditions are detected, the BRAKE warning light remains on:

  • The ECU connectors are disconnected from the skid control ECU.
  • The brake fluid level is insufficient.
  • The parking brake is applied.
  • The EBD system is malfunctioning.
  • The booster vacuum is malfunctioning.
  • The pedal stroke sensor is malfunctioning.
  • The pump is malfunctioning.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

When replacing the VSC actuator assembly, perform zero point calibration BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: CALIBRATION (2008 Sequoia) .

PROCEDURE

1.

PREPARE FOR INSPECTION

(a) Check that both of the following conditions are satisfied.

  • The brake fluid level in the brake master cylinder reservoir is correct.
  • The parking brake is released.

HINT:

  • When the ABS warning light remains illuminated, repair the malfunction in the ABS system first.
  • When the VSC OFF indicator light is blinking, repair the malfunction in the VSC system first.

NEXT

2.

CHECK DTC

(a) Check if any ABS DTCs are output BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: DTC CHECK / CLEAR (2008 Sequoia) .

Result

Result

Proceed to

DTC is not output

A

DTC is output

B
A

3.

CHECK CAN COMMUNICATION SYSTEM

(a) Check if the CAN communication system DTC is output NETWORKING: CAN COMMUNICATION SYSTEM: DIAGNOSIS SYSTEM (2008 Sequoia) .

Result

Result

Proceed to

DTC is not output

A

DTC is output

B
A

4.

CHECK CONNECTOR CONNECTION CONDITION

(a) Check if the skid control ECU connector is connected securely.

OK:

The connector is connected securely.

OK

5.

CHECK PARKING BRAKE SWITCH ASSEMBLY

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream ON.

(d) Select Data List mode and check the parking brake switch using the Techstream.

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

-

(e) Check that "ON" and "OFF" are properly indicated on the Techstream display when the parking brake lever is operated.

OK:

Techstream display changes in accordance with the parking brake lever operation.

OK

6.

CHECK BRAKE FLUID LEVEL WARNING SWITCH


(a) Remove the reservoir tank cap and strainer.

(b) Disconnect the A3 switch connector.

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

HINT:

A float is placed inside the reservoir. Its position can be changed by increasing or decreasing the brake fluid level.

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

1 (+) - 2 (E)

Float up (Switch OFF)

10 kΩ or higher

1 (+) - 2 (E)

Float down (Switch ON)

Below 1 Ω

HINT:

If the result is as specified, adjust the brake fluid level to the MAX level after measuring the resistance.

OK

7.

CHECK HARNESS AND CONNECTOR (COMBINATION METER - BRAKE FLUID LEVEL WARNING SWITCH)

(a) Disconnect the H37 meter connector.

(b) Disconnect the A3 switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A28-14 (SW) - A3-1 (+)

Always

Below 1 Ω

A28-14 (SW) - Body ground

Always

10 kΩ or higher

A3-2 (E) - Body ground

Always

Below 1 Ω
OK

8.

PERFORM ACTIVE TEST USING TECHSTREAM (BRAKE WARNING LIGHT)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream ON.

(d) Select Active Test mode and operate the BRAKE warning light using the Techstream.

ABS/VSC/TRAC

Tester Display

Test Part

Control Range

Diagnostic Note

Brake Warning Light

Brake warning light

Warning light ON/OFF

Observe combination meter

(e) Check that the BRAKE warning light turns on and off in the combination meter using the Techstream.

OK:

The BRAKE warning light turns ON and OFF in accordance with the Techstream operation.

OK

9.

INSPECT PARKING BRAKE SWITCH ASSEMBLY

(a) Disconnect the A5 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 switch ON

(Switch pin released)

Below 1 Ω

1 - Body ground

Parking brake switch OFF

(Switch pin pushed in)

10 kΩ or higher
OK

10.

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)

(a) Disconnect the A19 ECU connector.

(b) Disconnect the A5 switch connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A19-3 (PKB2) - A5-1

Always

Below 1 Ω

A19-3 (PKB2) - Body ground

Always

10 kΩ or higher
OK