Brake Warning Light Remains ON [10/2014 - 10/2015]: Procedure

1. Check if ABS, VSC and/or electronically controlled brake system DTCs are output (Refer to DTC CHECK / CLEAR [10/2014 - ] ).

   Result

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

Result: 

B 

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

(Refer to DIAGNOSTIC TROUBLE CODE CHART [10/2014 - 10/2015] )

Result: 

A 

See step  2

1. Check if CAN communication system DTCs are output (Refer to DIAGNOSIS SYSTEM [10/2014 - 10/2015] ).

   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 [10/2014 - 10/2015] )

Result: 

A 

See step  3

1. Check if the skid control ECU (brake booster with master cylinder assembly) connector is securely connected.

   OK

   The connector is securely connected.

Result: 

NG 

CONNECT CONNECTOR TO BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY CORRECTLY 

Result: 

OK 

See step  4

1. Check the auxiliary battery voltage.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Auxiliary battery	Power switch on (IG)	11 to 14 V
   Auxiliary battery	Power switch on (READY)	11 to 15.5 V

Result: 

NG 

CHARGE OR REPLACE AUXILIARY BATTERY 

Result: 

OK 

See step  5

1. Disconnect the A51 skid control ECU (brake booster with master cylinder assembly) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Turn the power switch on (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A51-16 (IG1) - Body ground	Power switch on (IG)	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT) 

Result: 

OK 

See step  6

1. Turn the power switch off.

   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
   A51-28 (GND) - Body ground	Always	Below 1 Ω
   A51-27 (GND2) - Body ground	Always	Below 1 Ω
   A51-26 (GND3) - Body ground	Always	Below 1 Ω
   A51-25 (GND4) - Body ground	Always	Below 1 Ω
   A51-24 (GND5) - Body ground	Always	Below 1 Ω
   A51-23 (GND6) - Body ground	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Skid Control ECU (Brake Booster with Master Cylinder Assembly))

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT) 

Result: 

OK 

See step  7

1. Reconnect the A51 skid control ECU (brake booster with master cylinder assembly) connector.
2. Connect the Techstream to the DLC3.
3. Turn the power switch on (IG).
4. Select the Data List on the Techstream (Refer to DATA LIST / ACTIVE TEST [10/2014 - 10/2015] ).
   ABS/VSC/TRAC
   
   

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

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

   OK

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

Result: 

NG 

See step  9

Result: 

OK 

See step  8

1. Select the Data List on the Techstream (Refer to DATA LIST / ACTIVE TEST [10/2014 - 10/2015] ).
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Brake Warning Light	Brake warning light / red (malfunction) / ON or OFF	ON: Warning light on OFF: Warning light off	-

2. Check the Techstream display condition of the brake warning light / red (malfunction).

   Result

   Result	Proceed to
   Display of the Data List remains OFF.	A
   Display of the Data List remains ON.	B

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the parts (Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] ).

Result: 

A 

INSPECT METER / GAUGE SYSTEM 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 10/2015] )

Result: 

B 

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

1. Turn the power switch off.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Disconnect the A27 parking brake switch assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1 (+) - Body ground	Parking brake switch assembly ON (Switch pin free)	Below 1 Ω
   1 (+) - Body ground	Parking brake switch assembly OFF (Switch pin pushed in)	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Parking Brake Switch Assembly)

Result: 

NG 

REPLACE PARKING BRAKE SWITCH ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

OK 

See step  10

1. Disconnect the 3D main body ECU (multiplex network body ECU) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3D-20 (PKB) - A27-1 (+)	Always	Below 1 Ω
   3D-20 (PKB) - Body ground	Always	10 kΩ or higher
   A27-1 (+) - Body ground	Always	10 kΩ or higher

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step before replacing the parts (Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] ).

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) 

(Refer to REMOVAL [10/2014 - 10/2015] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR