Lexus ES: Brake Hold Standby Indicator Light Circuit

DESCRIPTION

The brake hold standby indicator light turns on if brake hold control is possible when the following conditions required for operation standby are met and the brake hold switch (No. 3 combination switch assembly) is turned on while the power switch is on (IG).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

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PROCEDURE

(a) If the brake hold standby indicator light does not illuminate even though the brake hold switch (No. 3 combination switch assembly) is pushed, check that the brake hold function operation conditions are met.

HINT:

If a malfunction occurs in one of the following systems, the brake hold operated indicator light will blink. If this occurs, perform troubleshooting on the malfunctioning system.

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

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B

INSPECT CAN COMMUNICATION SYSTEM

A

(a) Check if the skid control ECU (brake booster with master cylinder assembly) connector is securely connected.

OK:

The connector is securely connected.

NG

CONNECT CONNECTOR TO BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CORRECTLY

OK

(a) Turn the power switch off.

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

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(c) Check the combination meter assembly.

OK:

The brake hold standby indicator light turns on or off in accordance with Techstream operation.

NG

INSPECT METER / GAUGE SYSTEM

OK

(a) Select the Active Test on the Techstream.

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(b) Check the operating condition of the brake hold standby indicator light when operating it using the Techstream.

A

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

B

(a) Turn the power switch off.

*a Component without harness connected (Brake Hold Switch (No. 3 Combination Switch Assembly))

(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(c) Disconnect the G45 brake hold switch (No. 3 combination switch assembly) connector.

(d) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Resistance:

NG

REPLACE NO. 3 COMBINATION SWITCH ASSEMBLY

OK

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.

OK:

The connector is securely connected.

(b) Disconnect the A45 skid control ECU (brake booster with master cylinder assembly) connector.

(c) Check both the connector case and the terminals for deformation and corrosion.

OK:

No deformation or corrosion.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Turn on the interior lights and check that they illuminate, and then set the switch so that the lights illuminate when the door is opened.

(b) Check that the lights illuminate when the driver side door is opened.

OK:

The interior lights illuminate when the driver side door is opened.

NG

INSPECT LIGHTING SYSTEM (COURTESY LIGHT SWITCH CIRCUIT)

OK

(a) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition A45-24 (CTY) - Body ground Driver door open Below 1.5 V A45-24 (CTY) - Body ground Driver door closed 11 to 14 V

*a Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

OK

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (CTY CIRCUIT)

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