DTC P0703-12: Brake Switch "B" Circuit Short to Battery [12/2019 - 10/2022]: Procedure

1. Read the Data List displayed on the GTS.

   Powertrain > Engine > Data List 

   Tester Display
   Stop Light SW

   OK

   GTS Display	Measurement Item/Range (display)	Normal Condition
   Stop Light SW	Stop light switch status: ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released

   Result

   Proceed to
   OK
   NG

Result: 

OK 

CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [12/2019 - 10/2022] 

Result: 

NG 

See step  2

Refer to INSTALLATION [12/2019 - ]

OK

Stop light switch assembly is installed correctly.

Result

Result: 

NG 

SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY. Refer to  INSTALLATION [12/2019 - ] 

Result: 

OK 

See step  3

1. Disconnect the 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
   A28-27 (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: 

OK 

REPLACE ECM. Refer to  REMOVAL [12/2019 - 09/2020]  , or refer to  REMOVAL [09/2020 - 10/2022] 

Result: 

NG 

See step  4

1. Disconnect the stop light switch assembly connector.
2. Disconnect the ECM connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A42-3 (L) or A28-27 (STP) - Other terminals	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)