DTC P0571-12: Brake Switch "A" Circuit Short to Battery [10/2020 - ]: Procedure

1. Check the brake pedal height and stop light switch assembly installation.

   Refer to ADJUSTMENT [10/2020 - 08/2021] , or refer to ADJUSTMENT [08/2021 - ]

   OK

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

   Result

   Proceed to
   OK
   NG

Result: 

NG 

ADJUST BRAKE PEDAL OR STOP LIGHT SWITCH ASSEMBLY. Refer to  ADJUSTMENT [10/2020 - 08/2021]  , or refer to  ADJUSTMENT [08/2021 - ] 

Result: 

OK 

See step  2

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   OK

   The connector is securely connected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (Stop Light Switch Assembly)

2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.
3. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A81-3 (L) - Body ground	Brake pedal released	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [10/2020 - ] 

Result: 

NG 

See step  3

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   OK

   The connector is securely connected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Stop Light Switch Assembly)

2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.
3. Disconnect the A81 stop light switch assembly connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A81-3 (L) - Body ground	Always	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [03/2017 - ] 

Result: 

NG 

See step  4

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   OK

   The connector is securely connected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Stop Light Switch Assembly)

2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.
3. Disconnect the A81 stop light switch assembly connector.
4. Disconnect the A24 ECM connector (for A25A-FKS).
5. Disconnect the A21 ECM connector (for 2GR-FKS).
6. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A81-3 (L) - Body ground	Always	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ECM 

for A25A-FKS: Refer to REMOVAL [10/2020 - 08/2022] , or refer to REMOVAL [08/2022 - ]

for 2GR-FKS: Refer to REMOVAL [10/2020 - 08/2022] , or refer to REMOVAL [08/2022 - ]

Result: 

NG 

See step  5

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   OK

   The connector is securely connected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Stop Light Switch Assembly)

2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.
3. Disconnect the A81 stop light switch assembly connector.
4. Disconnect the A24 ECM connector (for A25A-FKS).
5. Disconnect the A21 ECM connector (for 2GR-FKS).
6. Disconnect the K27 shift lock control ECU (shift lock control unit assembly) connector (w/ Smart Key System).
7. Disconnect the K28 shift lock control ECU (shift lock control unit assembly) connector (w/o Smart Key System).
8. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A81-3 (L) - Body ground	Always	Below 1.5 V

   Result

   Result	Proceed to
   OK	A
   NG (w/ Smart Key System)	B
   NG (w/o Smart Key System)	C

Result: 

A 

REPLACE SHIFT LOCK CONTROL UNIT ASSEMBLY 

for UB80E: Refer to REMOVAL [03/2017 - ]

for UB80F: Refer to REMOVAL [03/2020 - ]

Result: 

C 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

B 

See step  6

1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

   OK

   The connector is securely connected.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Stop Light Switch Assembly)

2. Disconnect the A34 skid control ECU (brake actuator assembly) connector.
3. Disconnect the A81 stop light switch assembly connector.
4. Disconnect the A24 ECM connector (for A25A-FKS).
5. Disconnect the A21 ECM connector (for 2GR-FKS).
6. Disconnect the K27 shift lock control ECU (shift lock control unit assembly) connector.
7. Disconnect the R8 certification ECU (smart key ECU assembly) connector.
8. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A81-3 (L) - Body ground	Always	Below 1.5 V

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SMART KEY ECU ASSEMBLY. Refer to  REMOVAL [10/2020 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR