ANTI-LOCK BRAKE SYSTEM 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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. CHECK CAN COMMUNICATION SYSTEM

   
   

   1. Check if CAN communication system DTCs are output.

      w/ Central Gateway ECU: Click here

      w/o Central Gateway ECU: Click here

      Result
      Result Proceed to DTCs are not output. A DTCs are output. B

   
   

   B

   INSPECT CAN COMMUNICATION SYSTEM w/ Central Gateway ECU: Click here INSPECT CAN COMMUNICATION SYSTEM w/o Central Gateway ECU: Click here

   A

2. CHECK IF BRAKE ACTUATOR ASSEMBLY CONNECTOR IS SECURELY CONNECTED

   
   

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

      OK
      The connector is securely connected.

      Result
      Proceed to OK NG

   
   

   NG

   CONNECT CONNECTOR TO ECU CORRECTLY

   OK

3. CHECK BATTERY

   
   

   1. Check the battery voltage.

      Standard Voltage
      11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY for 1NR-FE: Click here CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY for 1ZR-FE: Click here

   OK

4. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)

   
   
   1. 

      *a	Front view of wire harness connector (to Skid Control ECU (Brake Actuator Assembly))

      Disconnect the A120 skid control ECU (brake actuator assembly) connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition A120-25 (+BS) - Body ground Always 11 to 14 V A120-25 (+BS) - A120-38 (GND1) Always 11 to 14 V A120-28 (IG1) - Body ground Ignition switch ON 11 to 14 V A120-28 (IG1) - A120-38 (GND1) Ignition switch ON 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE TERMINAL)

   OK

5. CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

   
   
   1. 

      *a	Front view of wire harness connector (to Skid Control ECU (Brake Actuator Assembly))

      Turn the ignition switch off.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A120-38 (GND1) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)

   OK

6. INSPECT COMBINATION METER ASSEMBLY

   
   

   1. Reconnect the A120 skid control ECU (brake actuator assembly) connector.

   2. Perform an Active Test of the combination meter assembly using the GTS.

      Click here

      
      Body Electrical > Combination Meter > Active Test

      Tester Display
      Indicat. Lamp ABS

   3. Check the combination meter assembly.

      OK
      The ABS warning light turns on or off in accordance with the Active Test operation.

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing parts.

      Click here

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE BRAKE ACTUATOR ASSEMBLY Click here

   NG

   INSPECT METER / GAUGE SYSTEM Click here