Lexus NX: Brake Control Warning Light does not Come ON

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) is connected to the combination meter assembly via CAN communication.

CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake booster with master cylinder assembly), perform initialization and calibration of the linear solenoid valve.

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PROCEDURE

1.

CHECK CAN COMMUNICATION SYSTEM

(a) Check if CAN communication system DTCs are output.

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Result

Proceed to

DTCs are not output.

A

DTCs are output.

B

B

INSPECT CAN COMMUNICATION SYSTEM

A

2.

PERFORM ACTIVE TEST USING TECHSTREAM (BRAKE WARNING LIGHT / YELLOW (MINOR MALFUNCTION))

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Select the Active Test on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

ECB Warning Light

Brake warning light / yellow (minor malfunction)

Warning light ON/OFF

  • Observe combination meter assembly
  • ECB: Electronically Controlled Brake System

(d) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

ECB Warning Light

Brake warning light / yellow (minor malfunction)

ON or OFF

ON: Warning light on

OFF: Warning light off

ECB: Electronically Controlled Brake System

Chassis > ABS/VSC/TRAC > Active Test

Active Test Display

ECB Warning Light

Data List Display

ECB Warning Light

(e) Check the operating condition of the brake warning light / yellow (minor malfunction) when operating it using the Techstream.

Result

Proceed to

Brake warning light / yellow (minor malfunction) in the Data List does not change using the Active Test.

A

Brake warning light / yellow (minor malfunction) in the Data List turns ON/OFF using the Active Test.

B

A

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

B

3.

INSPECT COMBINATION METER ASSEMBLY

(a) Turn the power switch off.

(b) Perform the Active Test of the combination meter assembly (meter CPU) using the Techstream.

Click here

Body Electrical > Combination Meter > Active Test

Tester Display

Indicat. Lamp ECB

(c) Check the combination meter assembly.

OK:

The brake warning light / yellow (minor malfunction) turns on or off in accordance with the Techstream operation.

OK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

NG

INSPECT METER / GAUGE SYSTEM

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