Lexus IS250 IS220d GSE20 ALE20 - BRAKE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK CAN COMMUNICATION SYSTEM

CHECK MULTIPLEX COMMUNICATION SYSTEM

CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

CHECK BATTERY

INSPECT SKID CONTROL ECU (IG1 TERMINAL)

INSPECT SKID CONTROL ECU (GND TERMINAL)

INSPECT PARKING BRAKE SWITCH

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

INSPECT BRAKE FLUID LEVEL WARNING SWITCH

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

INSPECT COMBINATION METER ASSEMBLY

VEHICLE STABILITY CONTROL SYSTEM (w/o VDIM) - Brake Warning Light Remains ON

DESCRIPTION

The skid control ECU is connected to the combination meter via CAN and multiplex communications.


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


The skid control ECU connector is disconnected from the skid control ECU.
The brake fluid level is insufficient.
The parking brake is applied.
The EBD is defective.

WIRING DIAGRAM

Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • NOTICE:
  • When replacing the brake actuator assembly, perform zero point calibration .
1.CHECK CAN COMMUNICATION SYSTEM

Check if the CAN communication system DTC is output ( for LHD (gasoline), for RHD (gasoline), for LHD (diesel), or for RHD (diesel)).

  • Result:
  • ConditionProceed to
    DTC is not outputA
    DTC is outputB
B
INSPECT CAN COMMUNICATION SYSTEM
A
2.CHECK MULTIPLEX COMMUNICATION SYSTEM

Check if the multiplex communication system DTC is output .

  • Result:
  • ConditionProceed to
    DTC is not outputA
    DTC is outputB
B
INSPECT MULTIPLEX COMMUNICATION SYSTEM
A
3.CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED

Check if the skid control ECU connector is securely connected.

  • OK:
  • The connector should be securely connected.
NG
CONNECT CONNECTOR TO ECU CORRECTLY
OK
4.CHECK BATTERY

Check the battery voltage.

  • Standard voltage:
  • 11 to 14 V
NG
CHECK AND REPLACE CHARGING SYSTEM OR BATTERY
OK
5.INSPECT SKID CONTROL ECU (IG1 TERMINAL)
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the skid control ECU connector.

Turn the engine switch on (IG).

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    A14-46 (IG1) - Body groundEngine switch on (IG)10 to 14 V
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK
6.INSPECT SKID CONTROL ECU (GND TERMINAL)
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Turn the engine switch off.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    A14-32 (GND1) - Body groundAlwaysBelow 1 Ω
    A14-1 (GND2) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK
7.INSPECT PARKING BRAKE SWITCH
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the parking brake switch connector.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    1 - Body groundParking brake switch ON
    (Switch pin free)
    Below 1 Ω
    1 - Body groundParking brake switch OFF
    (Switch pin pushed in)
    10 kΩ or higher
NG
REPLACE PARKING BRAKE SWITCH
OK
8.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

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

  • Standard resistance:
  • A/T:
  • Tester ConnectionConditionSpecified Condition
    A14-28 (PKB) - A25-1AlwaysBelow 1 Ω
    A14-28 (PKB) - Body groundAlways10 kΩ or higher
  • M/T:
  • Tester ConnectionConditionSpecified Condition
    A14-28 (PKB) - J88-1AlwaysBelow 1 Ω
    A14-28 (PKB) - Body groundAlways10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
9.INSPECT BRAKE FLUID LEVEL WARNING SWITCH
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Remove the reservoir tank cap and strainer.

Disconnect the brake fluid level warning switch connector.

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/decreasing the level of brake fluid.
  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    1 - 2Float up (Switch OFF)1.9 to 2.1 kΩ
    1 - 2Float down (Switch ON)Below 1 Ω
  • HINT:
  • If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.
NG
REPLACE BRAKE MASTER CYLINDER RESERVOIR SUB-ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH)
OK
10.CHECK HARNESS AND CONNECTOR (COMBINATION METER - BRAKE FLUID LEVEL WARNING SWITCH)
Vehicle Stability Control System (W/O Vdim) - Brake Warning Light Remains On. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Disconnect the combination meter connector.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    J35-15 (SW) - A16-1 (+)AlwaysBelow 1 Ω
    J35-15 (SW) - Body groundAlways10 kΩ or higher
    A16-2 (E) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
11.INSPECT COMBINATION METER ASSEMBLY

Perform Active Test of the combination meter (meter CPU) using the intelligent tester .

  • OK:
  • The BRAKE warning light turns on or off in accordance with the intelligent tester.
  • HINT:
Reinstall the connectors and restore the vehicle to its prior condition before checking the combination meter.
If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the part .
NG
REPLACE COMBINATION METER ASSEMBLY
OK
REPLACE BRAKE ACTUATOR ASSEMBLY