Lexus ES manuals

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 pressed while the engine switch on (IG).

  • Conditions required for operation standby:
    1. The driver door is closed.
    2. The driver seat belt is fastened.
    3. The system is normal.

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.

  • Brake system
  • Electric parking brake system

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake actuator assembly), perform acceleration sensor zero point calibration and store system information memorization.

Click here

PROCEDURE

1.

PRE-CHECK

(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.

  1. The driver door is closed.
  2. The driver seat belt is fastened.
  3. The system is normal.

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.

  • Brake system
  • Electric parking brake system
NEXT

2.

READ VALUE USING TECHSTREAM (BRAKE HOLD READY)

(a) Connect the Techstream to the DLC3.

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

(c) Enter the following menus: Chassis / Brake/EPB / Data List.

Chassis > Brake/EPB > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Brake Hold Ready

Brake hold control permission status

Not in stand-by mode / Stand-by mode

Not in stand-by mode: Brake hold function not operating (brake hold indicator not illuminated)

Stand-by mode: Brake hold function stand-by state (brake hold indicator illuminated)

-

Chassis > Brake/EPB > Data List

Tester Display

Brake Hold Ready

(d) All of the following brake hold operation conditions are met:

  1. The driver door is closed.
  2. The driver seat belt is fastened.

(e) Check the brake hold standby indicator light and mode condition on the Techstream changes according to brake hold switch (No. 3 combination switch assembly) operation.

Standard:

Brake Hold Switch (No. 3 Combination Switch Assembly) Operation

Mode Condition Display

Brake Hold Standby Indicator Light

Not pressed

Not in stand-by mode

Does not come on

Pressing the brake hold switch (No. 3 combination switch assembly)

Stand-by mode

come on

Result

Proceed to

Indicator light and mode condition display do not change

A

Mode condition display is normal, but indicator light does not change

B

Indicator light and mode condition display are normal

C

B

INSPECT METER / GAUGE SYSTEM

C

USE SIMULATION METHOD TO CHECK

A

3.

INSPECT NO. 3 COMBINATION SWITCH ASSEMBLY

(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.

*a

Component without harness connected

(Brake Hold Switch (No. 3 Combination Switch Assembly))

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

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

OK:

No deformation or corrosion.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4 (+B) - 2 (E)

Switch pushed

Below 1 Ω

4 (+B) - 2 (E)

Switch not pushed

10 kΩ or higher

NG

REPLACE NO. 3 COMBINATION SWITCH ASSEMBLY

OK

4.

CHECK HARNESS AND CONNECTOR (NO. 3 COMBINATION SWITCH ASSEMBLY - BRAKE ACTUATOR ASSEMBLY)

(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 A40 skid control ECU (brake actuator assembly) connector.

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

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

OK:

No deformation or corrosion.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

G45-4 (+B) - A40-42 (EXI3)

Always

Below 1 Ω

G45-4 (+B) or A40-42 (EXI3) - Body ground

Always

10 kΩ or higher

G45-2 (E) - Body ground

Always

Below 1 Ω

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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 System Description

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 Components

COMPONENTS ILLUSTRATION *A w/ Stud Bolt - - *1 CONNECTING ROD BEARING *2 CRANKSHAFT *3 CRANKSHAFT BEARING *4 CRANKSHAFT THRUST WASHER SET *5 CYLINDER BLOCK SUB-ASSEMBLY *6 NO. 1 OIL NOZZLE SUB-ASSEMBLY *7 PISTON *8 PISTON RING SET *9 STUD BOLT

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