Brake Warning Light Circuit: Procedure

1. Turn the ignition switch ON.
2. Check that the ABS warning light turns on.
3. Check for DTC. Refer to DTC CHECK / CLEAR .
   RESULT
   
   

   Result	Proceed to
   DTC is not output	A
   DTC is output	B

B → REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

A: Go to next step 

1. Using the Techstream Active Test, generate a control command and then check that the brake warning light operates.
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Brake Warning Light	Turns brake warning light ON/OFF	Observe combination meter	-

   OK

   Brake warning light is turned on or off in accordance with the Techstream.

OK → REPLACE SKID CONTROL ECU 

NG: Go to next step 

Fig 1: Identifying Parking Brake Switch

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the parking brake switch.
2. Measure the resistance of the switch.

   Standard resistance

   Tester Connection	Switch Condition	Specified Condition
   1 - Ground part	Released	Below 1 Ω
   1 - Ground part	Pushed	10 kΩ or higher

NG → REPLACE PARKING BRAKE SWITCH 

OK: Go to next step 

Fig 2: Identifying Brake Fluid Level Warning Switch

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the reservoir tank cap and strainer.
2. Disconnect the B4 switch connector.
3. Measure the resistance of the switch.

   Standard resistance

   Tester Connection	Switch Condition	Specified Condition
   1 - 2	Float up	10 kΩ or higher
   1 - 2	Float down	Below 1 Ω

NG → REPLACE BRAKE ACTUATOR 

OK: Go to next step 

Fig 3: Checking Wire Harness (Skid Control ECU - Parking Brake Switch)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the S6 ECU connector.
2. Disconnect the P3 switch connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   S6-8 (PKB) - P3-1	Below 1 Ω
   S6-8 (PKB) - Body ground	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step 

Fig 4: Checking Wire Harness (Brake Fluid Level Warning Switch - Skid Control ECU And Body Ground)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the B4 switch connector.
2. Disconnect the S5 ECU connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester Connection	Specified Condition
   S5-12 (LBL) - B4-2	Below 1 Ω
   S5-12 (LBL) - Body ground	10 kΩ or higher
   B4-1 - Body ground	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step 

1. Check for open and short circuits in the multiplex communication system between the skid control ECU and combination meter.

NG → REPAIR OR REPLACE MULTIPLEX COMMUNICATION SYSTEM 

OK: Go to next step 

1. Check the combination meter. Refer to PROBLEM SYMPTOMS TABLE .

NG → REPAIR OR REPLACE COMBINATION METER 

OK → REPLACE SKID CONTROL ECU