Inspection Procedure

WARNING: This page is about a different car, the 2007 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.

READ VALUE OF INTELLIGENT TESTER (STOP LIGHT SWITCH)

Check the DATA LIST for proper functioning of the stop light switch.

Driver side junction block ECU

DATA LIST - DRIVER SIDE JUNCTION BLOCK ECU

Item	Measurement Item / Display (Range)	Normal Condition	Diagnostic Note
STOP LIGHT SW	Stop light switch / ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

OK: ON (brake pedal is depressed) appears on the screen.

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

NG: Go to Next step

INSPECT STOP LIGHT SWITCH ASSEMBLY

Fig 1: Inspecting Stop Light Switch Assembly

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Remove the stop light switch.

Measure the resistance of the switch.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
1 - 2	Pushed	Below 1 Ω
1 - 2	Not pushed	10 kΩ higher

NG: REPLACE STOP LIGHT SWITCH ASSEMBLY

OK: Go to Next step

CHECK WIRE HARNESS (SWITCH - DRIVER SIDE JUNCTION BLOCK ECU AND BATTERY)

Fig 2: Identifying Stop Light Switch And Driver Side Junction Block ECU Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the S10 switch connector.
Disconnect the D2 ECU connector.

Disconnect the voltage of the wire harness side connectors.

Standard voltage

VOLTAGE SPECIFICATION

Tester Connection	Specified Condition
S10-2 - Body ground	10 to 14 V

Measure the resistance of the wire harness side connectors.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
S10-1 - D2-13(STP1)	Below 1 Ω
S10-1 - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: Go to Next step

CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - ECM)

Fig 3: Identifying Driver Side Junction Block ECU And ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Disconnect the D2 ECU connector.
Disconnect the E5 ECM connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
D2-12 (STPO) - E5-4 (STP)	Below 1 Ω
D2-12 (STPO) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: Go to Next step

CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - SHIFT CONTROL ECU)

Fig 4: Identifying Driver Side Junction Block ECU And Shift Control ECU Connector Terminals

Disconnect the D4 ECU connector.
Disconnect the S4 ECU connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
D4-4 (STP) - S4-9 (STP)	Below 1 Ω
D4-4 (STP) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: Go to Next step

CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - SHIFT CONTROL ECU)

Fig 5: Identifying Driver Side Junction Block ECU And Shift Control ECU Connector Terminals

Disconnect the D4 ECU connector.
Disconnect the S7 ECU connector.

Measure the resistance of the wire harness side connectors.

Standard resistance

RESISTANCE SPECIFICATION

Tester Connection	Specified Condition
D4-4 (STP) - S7-9 (STP)	Below 1 Ω
D4-4 (STP) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE