DTC P0703-12: Brake Switch "B" Circuit Short to Battery [10/2017 - ]: Procedure

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Powertrain / Transmission / Data List / Stop Light SW.
6. Read the Data List according to the display on the Techstream.

   Powertrain > Transmission > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Stop Light SW	Stop light switch assembly status	ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

   Powertrain > Transmission > Data List 

   Tester Display
   Stop Light SW

   Result

   Result	Proceed to
   Data List value is normal	A
   Data List value is not normal	B

Result: 

A 

CHECK FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2017 - 09/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 09/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - ] 

Result: 

B 

See step  2

1. Check the stop light switch assembly installation.

   Refer to INSTALLATION [04/2013 - ]

   OK

   Stop light switch assembly is installed correctly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY. Refer to  INSTALLATION [04/2013 - ] 

Result: 

OK 

See step  3

1. Inspect the stop light switch assembly.

   Refer to ON-VEHICLE INSPECTION [04/2013 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  COMPONENTS [04/2013 - 09/2020]  , or refer to  COMPONENTS [09/2020 - ] 

Result: 

OK 

See step  4

1. Disconnect the A106 ECM connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Brake pedal depressed	*b	Brake pedal released
   *c	Front view of wire harness connector (to ECM)	-	-

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A106-27 (STP) - Body ground	Brake pedal released	Below 1.5 V
   	Brake pedal depressed	7.5 to 14 V

   HINT: 

   If there is a short in the STP terminal circuit, there may be a malfunction in the circuit of a connected ECU.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Replace the ECM.

   Refer to COMPONENTS [10/2017 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

PERFORM A/T CODE REGISTRATION. Refer to  REGISTRATION [10/2017 - ]