Dtc P0571/76 Brake Switch A Circuit

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK STOP LIGHT OPERATION

CHECK HARNESS AND CONNECTOR (MASTER CYLINDER SOLENOID STPO TERMINAL VOLTAGE)

CHECK HARNESS AND CONNECTOR (MASTER CYLINDER SOLENOID STP2 TERMINAL VOLTAGE)

PERFORM ACTIVE TEST USING GTS (STOP LIGHT RELAY)

INSPECT STP LP OPE RELAY (BRAKE LIGHT RELAY)

CHECK HARNESS AND CONNECTOR (STP LP OPE RELAY - BATTERY)

CHECK HARNESS AND CONNECTOR (STP LP OPE RELAY - MASTER CYLINDER SOLENOID AND BATTERY)

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:

1. Inspect the fuses for circuits related to this system before performing the following procedure.
   
2. After replacing the master cylinder solenoid, perform zero point calibration and store the system information (Click here).
   
3. When the start function does not operate, check the smart key system (for start function) (Click here).
   

1. Check that the stop lights come on when the brake pedal is depressed and go off when the brake pedal is released.
   

   OK:

   Condition	Illumination Condition
   Brake pedal depressed	On
   Brake pedal released	Off

1. Disconnect the skid control ECU (master cylinder solenoid) connector.
   

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   A24-16 (STPO) - Body ground	Always	11 to 14 V

   Text in Illustration

   *a	Front view of wire harness connector (to Skid Control ECU [Master Cylinder Solenoid])

1. Disconnect the skid control ECU (master cylinder solenoid) connector.
   

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   A24-45 (STP2) - Body ground	Brake pedal depressed	11 to 14 V

   Text in Illustration

   *a	Front view of wire harness connector (to Skid Control ECU [Master Cylinder Solenoid])

1. Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.
   

2. Perform the Active Test according to the display on the GTS.
   
   

   ABS/VSC/TRAC

   Tester Display	Test Part	Control Range	Diagnostic Note
   Stop Light Relay	STP LP OPE relay (Brake light relay)	Relay ON/OFF	Observe the stop light (the stop lights do not come on for 2 to 5 seconds).

3. Check the STP LP OPE relay (brake light relay) operation using the Data List and stop light operation by performing an Active Test.
   
   

   ABS/VSC/TRAC

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Stop Light Relay Output	STP LP OPE relay (Brake light relay) output/ ON or OFF	ON: Relay output on (Stop light on) OFF: Relay output off (Stop light off)	-

   
   

   Result:

   
   

   Result	Proceed to
   The Data List item "Stop Light Relay Output" switches between ON and OFF when turning the stop light control relay on and off with the Active Test, but the stop lights do not illuminate or turn off	A
   The Data List item "Stop Light Relay Output" does not switch between ON and OFF when turning the stop light control relay on and off with the Active Test (for LHD)	B
   The Data List item "Stop Light Relay Output" switches between ON and OFF when turning the stop light control relay on and off with the Active Test and the stop lights illuminate and turn off (for LHD)
   The Data List item "Stop Light Relay Output" does not switch between ON and OFF when turning the stop light control relay on and off with the Active Test (for RHD)	C
   The Data List item "Stop Light Relay Output" switches between ON and OFF when turning the stop light control relay on and off with the Active Test and the stop lights illuminate and turn off (for RHD)

1. Turn the engine switch off.
   

2. Remove the STP LP OPE relay (brake light relay) from the engine room relay block and junction block assembly.
   

3. Inspect the STP LP OPE relay (brake light relay) (Click here).
   

1. Turn the engine switch off.
   

2. Remove the STP LP OPE relay (brake light relay) from the engine room relay block and junction block assembly.
   

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   STP LP OPE relay (brake light relay) holder terminal 5 - Body ground	Always	11 to 14 V

   Text in Illustration

   *1	Engine Room Relay Block and Junction Block Assembly
   *2	STP LP OPE Relay (Brake Light Relay) Holder Terminal

   Result:

   Result	Proceed to
   OK (for LHD)	A
   OK (for RHD)	B
   NG	C

1. Turn the engine switch off.
   

2. Remove the STP LP OPE relay (brake light relay) from the engine room relay block and junction block assembly.
   

3. Disconnect the A24 skid control ECU (master cylinder solenoid) connector.
   

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

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   STP LP OPE relay (brake light relay) holder terminal 2 - A24-16 (STPO)	Always	Below 1 Ω
   STP LP OPE relay (brake light relay) holder terminal 2 or A24-16 (STPO) - Body ground	Always	10 kΩ or higher

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

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   STP LP OPE relay (brake light relay) holder terminal 1 - Body ground	Engine switch on (IG)	11 to 14 V

   Text in Illustration

   *1	Engine Room Relay Block and Junction Block Assembly
   *2	STP LP OPE Relay (Brake Light Relay) Holder Terminal