DTC P0703-12: Brake Switch "B" Circuit Short to Battery [08/2020 - 08/2021]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine / Data List / Stop Light SW.

   Powertrain > Engine > Data List 

   Tester Display
   Stop Light SW

5. Read the Data List displayed on the Techstream.

   OK

   Techstream 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 [06/2018 - ] 

Result: 

NG 

See step  2

1. Check the stop light switch assembly installation.

   Refer to INSTALLATION [06/2018 - ]

   OK

   Stop light switch assembly is installed correctly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY. Refer to  INSTALLATION [06/2018 - ] 

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	Brake Pedal Operation	Specified Condition
   A25-27 (STP) - Body ground	Released	Below 1.5 V
   	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 [10/2019 - 08/2021] 

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
   A80-3 (L) or A25-27 (STP) - Other terminals	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [06/2018 - ] 

Result: 

NG 

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