ABS Warning Light Remains ON [04/2018 - 08/2020]: Procedure

1. Check if CAN communication system DTCs are output.

   Refer to HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -]

   Result

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

Result: 

B 

INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -] 

Result: 

A 

See step  2

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

Result: 

NG 

CONNECT CONNECTOR TO BRAKE ACTUATOR ASSEMBLY CORRECTLY 

Result: 

OK 

See step  3

1. Check the battery voltage.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Positive (+) terminal - Negative (-) terminal	Engine switch off	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CHECK OR REPLACE CHARGING SYSTEM COMPONENT OR BATTERY. Refer to  ON-VEHICLE INSPECTION [04/2018 -] 

Result: 

OK 

See step  4

1. Turn the engine switch off.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   OK

   The connector is securely connected.

3. Disconnect the A28 skid control ECU (brake actuator assembly) connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A28-30 (+BS) - Body ground	Always	11 to 14 V
   A28-36 (IG1) - Body ground	Engine switch on (IG)	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

Result: 

OK 

See step  5

1. Turn the engine switch off.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A28-46 (GND1) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) 

Result: 

OK 

See step  6

1. Reconnect the A28 skid control ECU (brake actuator assembly) connector.
2. Enter the following menus: Chassis / ABS/VSC/TRAC/EPB / Data List.

   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

3. Check the Techstream display condition of the ABS warning light.

   Result

   Result	Proceed to
   The value of ABS Warning Light is ON	A
   The value of ABS Warning Light is OFF	B

Result: 

A 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [04/2018 - 08/2020] 

Result: 

B 

INSPECT METER / GAUGE SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2018 -]