Toyota CH-R Service Manual: ABS Warning Light Remains ON

DESCRIPTION

The skid control ECU (brake actuator assembly) is connected to the combination meter assembly via CAN communication. If any of the following is detected, the ABS warning light remains on:

  • The skid control ECU (brake actuator assembly) connector is disconnected from the skid control ECU (brake actuator assembly).
  • There is a malfunction in the skid control ECU (brake actuator assembly) internal circuit.
  • There is an open in the harness between the combination meter and skid control ECU (brake actuator assembly).
  • The ABS is defective.

HINT:

In some cases, the Techstream cannot be used when the skid control ECU (brake actuator assembly) is abnormal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • When replacing the skid control ECU (brake actuator assembly), perform system variant learning.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK CAN COMMUNICATION SYSTEM

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

Click here

Result

Proceed to

DTCs are not output.

A

DTCs are output.

B

B

INSPECT CAN COMMUNICATION SYSTEM

A

2.

CHECK IF BRAKE ACTUATOR ASSEMBLY CONNECTOR IS SECURELY CONNECTED

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

OK:

The connector is securely connected.

NG

CONNECT CONNECTOR TO ECU CORRECTLY

OK

3.

CHECK BATTERY

(a) Check the battery voltage.

Standard Voltage:

11 to 14 V

NG

CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY

OK

4.

CHECK HARNESS AND CONNECTOR (POWER SOURCE (IG1) TERMINAL)

(a) Disconnect the A42 skid control ECU (brake actuator assembly) connector.

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A42-30 (+BS) - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE TERMINAL)

OK

5.

CHECK HARNESS AND CONNECTOR (POWER SOURCE (IG1) TERMINAL)

(a) Disconnect the A42 skid control ECU (brake actuator assembly) connector.

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A42-36 (IG1) - Body ground

Ignition switch ON

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE TERMINAL)

OK

6.

CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

(a) Turn the ignition switch off.

*a

Front view of wire harness connector

(to Skid Control ECU (Brake Actuator Assembly))

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A42-46 (GND1) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

OK

7.

READ VALUE USING TECHSTREAM (ABS WARNING LIGHT)

(a) Reconnect the A42 skid control ECU (brake actuator assembly) connector.

(b) Select the Data List on the Techstream.

Click here

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

ABS Warning Light

ABS warning light

ON or OFF

ON: Warning light on

OFF: Warning light off

-

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display

ABS Warning Light

(c) Check the Techstream display condition of the ABS warning light.

Result

Proceed to

ON is displayed.

A

OFF is displayed.

B

A

REPLACE BRAKE ACTUATOR ASSEMBLY

B

INSPECT METER / GAUGE SYSTEM

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