Ignition Switch Circuit: Procedure

READ VALUE USING TECHSTREAM

Select the items below in the Data List and read the display on Techstream.

MAIN BODY:

Item	Measurement Item/Range	Normal Condition	Diagnostic Note
IG SW	Ignition switch ON signal ON/OFF	ON: Ignition switch is in the ON position OFF: Ignition switch is OFF	-
ACC SW	Ignition switch ACC signal ON/OFF	ON: Ignition switch is in the ACC position OFF: Ignition switch is OFF	-

When the ignition switch is operated, the display changes as shown in the table.

NG → See step 3

OK → See step 2

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE

CHECK HARNESS AND CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK)

Disconnect the 1A junction block connector.

Fig 1: Identifying 1A Junction Block Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard voltage

Tester Connection	Condition	Specified Condition
1A-1 - Body ground	Ignition switch ON	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

INSPECT IGNITION SWITCH ASSEMBLY

Disconnect the D70 ignition switch connector.

Fig 2: Identifying D24 Ignition Switch Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard resistance

Tester Connection	Condition	Specified Condition
1 - 4	Ignition switch ON	Below 1 Ω
2 - 4	Ignition switch ACC	Below 1 Ω

NG → See step 7

OK: Go to next step

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL J/B - INSTRUMENT PANEL J/B)

Disconnect the 1I junction block connector.

Fig 3: Identifying 1I Junction Block Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard resistance

Tester Connection	Condition	Specified Condition
1I-4 - 1I-9	Ignition switch ON	Below 1 Ω
1I-4 - 1I-3	Ignition switch ACC	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step

CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - BODY GROUND)

Disconnect the 1F junction block connector.

Fig 4: Identifying 1F Junction Block Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard resistance

Tester Connection	Condition	Specified Condition
1F-10 - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK → REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)