OBD II scan tool (excluding hand-held tester):

CHECK OPERATION OF STOP LIGHT
1. Check if the stop lights go on and off normally when the brake pedal is depressed and released.
1. NG: REPAIR OR REPLACE STOP LIGHT SWITCH CIRCUIT
2. OK: Go to next step.
INSPECT STOP LIGHT SWITCH ASSY
1. Check the resistance between the terminals when the switch is turned ON and OFF.
  Standard:
  
  Fig 1: Connector Specified Condition Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: Checking Resistance Between Terminals When Switch Turned ON And OFF
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE STOP LIGHT SWITCH ASSY
2. OK: Go to next step.
INSPECT ECM (STP VOLTAGE)
1. Turn the ignition switch ON.
2. Measure the voltage between the terminals of the E4 and E5 ECM connectors.
  Standard:
  
  Fig 3: Connector Specified Condition
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 4: Measuring Voltage Between Terminal Of E4 And E5 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
2. NG: Go to next step.

CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM)

Check the resistance between the wire harness side connectors.

Standard (Check for open):

CONNECTOR (OPEN) SPECIFIED CONDITION

Between Terminals	Specified Condition
Stop light switch (S7-1) - STP (E5-19)	Below 1 Ω

Fig 5: Identifying Stop Light Switch Connector Wire Harness Side

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for short):

CONNECTOR (SHORT) SPECIFIED CONDITION

Between Terminals	Specified Condition
Stop light switch (S7-1) or STP (E5-19) - Body ground	10 kΩ or higher

Reconnect the ECM connector.
Reconnect the stop light switch connector.

Fig 6: Disconnecting E5 ECM Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002