DTC P0571-11: Brake Switch "A" Circuit Short to Ground [08/2019 - ]: Procedure

1. Check the brake pedal height installation.

   Refer to ADJUSTMENT [08/2015 - ]

2. Check the stop light switch assembly installation.

   Refer to INSTALLATION [08/2015 - ]

   OK

   The brake pedal height and stop light switch assembly installation are normal.

   HINT: 

   If the on/off status of the stop light switch assembly and pressure increase information from the master cylinder pressure sensor do not match due to an improperly installed brake pedal or stop light switch assembly, this DTC may be stored. Therefore, be sure to check the installation condition of the pedal and switch before inspecting the input signals and other related parts.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY. Refer to  ADJUSTMENT [08/2015 - ] 

Result: 

OK 

See step  2

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  3

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Select the Data List using the Techstream.

   Refer to DATA LIST / ACTIVE TEST [08/2019 - ]

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Stop Light SW	Stop light switch assembly (STP terminal input)	ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	HINT:  The brake pedal state is determined using the voltage at terminal STP
   Brake Pedal Load Sensing SW	Brake pedal load sensing switch	ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

4. Check that the stop light switch display observed on the Techstream changes according to brake pedal operation.

   OK

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

   Result

   Result	Proceed to
   OK	A
   NG (The stop light switch assembly does not turn on.)	B
   NG (Turning on of the brake pedal load sensing switch is not confirmed.)	C
   NG (The brake pedal load sensing switch turns on first.)	D

Result: 

B 

See step  5

Result: 

C 

See step  7

Result: 

D 

REPLACE BRAKE PEDAL SUPPORT ASSEMBLY. Refer to  REMOVAL [08/2015 - ] 

Result: 

A 

See step  4

1. Turn the ignition switch off.
2. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

3. Start the engine.
4. Depress the brake pedal several times to test the stop light circuit.
5. Check if the same DTC is recorded.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   Result

   Result	Proceed to
   DTC P0571-11 is not output.	A
   DTC P0571-11 is output.	B

   HINT: 

   If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step.

   Refer to PROBLEM SYMPTOMS TABLE [08/2019 - ]

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

1. Turn the ignition switch off.
2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

3. Disconnect the A58 skid control ECU (brake actuator assembly) connector.
4. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A58-35 (STP) - Body ground	Stop light switch ON (Brake pedal depressed)	8 to 14 V
   	Stop light switch assembly off (Brake pedal released)	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP CIRCUIT) 

Result: 

OK 

See step  6

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

   Tester Connection	Condition	Specified Condition
   A58-25 (GND1) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) 

1. Inspect the brake pedal load sensing switch (brake pedal support assembly).

   OK

   The brake pedal load sensing switch (brake pedal support assembly) is normal.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE BRAKE PEDAL SUPPORT ASSEMBLY. Refer to  REMOVAL [08/2015 - ] 

Result: 

OK 

See step  8

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
2. Disconnect the A58 skid control ECU (brake actuator assembly) connector.
3. Measure the resistance according to the value(s) in the table below.

   Tester Connection	Condition	Specified Condition
   A58- 27 (FSW+) - A55- 2 (FSW+)	Always	Below 1 Ω
   A58- 27 (FSW+) or A55- 2 (FSW+) - Body ground	Always	10 kΩ or higher
   A55- 1 (FSW-) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Inspect the stop light switch assembly.

   Refer to ON-VEHICLE INSPECTION [08/2019 - ]

   OK

   The stop light switch assembly is normal.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE STOP LAMP SWITCH ASSEMBLY. Refer to  REMOVAL [08/2015 - ] 

Result: 

OK 

See step  10

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
2. Disconnect the A58 skid control ECU (brake actuator assembly) connector.
3. Measure the voltage according to the value(s) in the table below.
   STANDARD VOLTAGE:
   
   

   Tester Connection	Condition	Specified Condition
   A58-35 (STP) - Body ground	Stop light switch assembly on (Brake pedal depressed)	8 to 14 V
   A58-35 (STP) - Body ground	Stop light switch assembly off (Brake pedal released)	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (STP TERMINAL) 

Result: 

OK 

See step  11

1. Reconnect the A58 skid control ECU (brake actuator assembly) connector.
2. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

3. Turn the ignition switch off.
4. Start the engine.
5. Depress the brake pedal several times to test the stop light circuit.
6. Check if the same DTC is output.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   Result

   Result	Proceed to
   DTC P0571-11 is not output.	A
   DTC P0571-11 is output.	B

Result: 

A 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - ] 

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [08/2019 - ]