Brake Warning Light Remains ON: Procedure

1. Check if an ABS, VSC and/or electronically controlled brake system DTC is output, refer to DTC CHECK / CLEAR .

   Result

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

B → See step   12 

A: Go to next step 

B → See step   13 

C → See step   16 

A: Go to next step 

1. Check if the skid control ECU connector is securely connected.

   OK

   The connector is securely connected.

NG → CONNECT CONNECTOR TO ECU CORRECTLY 

OK: Go to next step 

1. Check the auxiliary battery voltage.

   Standard Voltage

   11 to 14 V

NG → CHARGE OR REPLACE AUXILIARY BATTERY 

OK: Go to next step 

1. Disconnect the A44 skid control ECU connector.
   Fig 1: Identifying Skid Control ECU Control Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   A44-2 (IG1) - Body ground	Ignition switch ON	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Skid Control ECU)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT) 

OK: Go to next step 

1. Turn the ignition switch off.
   Fig 2: Identifying Skid Control ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1

   Front view of wire harness connector (to Skid Control ECU)

   -

   -

2. Disconnect the A45, A46 and A47 skid control ECU connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A46-1 (GND) - Body ground	Always	Below 1 Ω
   A44-3 (GND2) - Body ground	Always	Below 1 Ω
   A44-1 (GND3) - Body ground	Always	Below 1 Ω
   A47-3 (GND4) - Body ground	Always	Below 1 Ω
   A47-1 (GND5) - Body ground	Always	Below 1 Ω
   A45-3 (GND6) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT) 

OK: Go to next step 

1. Reconnect the skid control ECU connectors.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Select the Data List on the Techstream, refer to DATA LIST / ACTIVE TEST .
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Parking Brake SW	Parking brake switch / ON or OFF	ON: Parking brake applied OFF: Parking brake released	-

5. Using the Techstream, check that the switch condition displayed on the Techstream changes according to parking brake operation.

   OK

   The Techstream displays ON and OFF according to parking brake operation.

NG → See step   9 

OK: Go to next step 

1. Turn the ignition switch off.
2. Perform the Active Test of the combination meter (meter CPU) using the Techstream, refer to DATA LIST / ACTIVE TEST .
3. Check the combination meter.

   OK

   The brake warning light / red (malfunction) turns on and off in accordance with the Techstream operation.

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next suspected area before replacing the part, refer to PROBLEM SYMPTOMS TABLE .

NG → See step   14 

OK → See step   11 

1. Turn the ignition switch off.
   Fig 3: Identifying Parking Brake Switch Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the parking brake switch connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   1 - Body ground	Parking brake switch ON (Switch pin not pushed in)	Below 1 Ω
   1 - Body ground	Parking brake switch OFF (Switch pin pushed in)	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Parking Brake Switch)

NG → See step   15 

OK: Go to next step 

1. Disconnect the 1C main body ECU connector.
   Fig 4: Identifying 1C Main Body ECU Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1C-14 (PKB) - A17-1	Always	Below 1 Ω
   1C-14 (PKB) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Main Body ECU)
   *2	Front view of wire harness connector (to Parking Brake Switch)

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next suspected area before replacing the part, refer to PROBLEM SYMPTOMS TABLE .

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)