Ignition Switch Circuit

DESCRIPTION

This circuit detects the state of the ignition switch and sends it to the body ECU.

WIRING DIAGRAM

INSPECTION PROCEDURE

1. READ VALUE OF INTELLIGENT TESTER

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to the ON position and press the intelligent tester main switch ON.

3. Select the items below in the DATA LIST, and read the displays on the intelligent tester.

   BODY NO.1: 

   Item	Measurement Item/ Display (Range)	Normal Condition	Diagnostic Note
   ACC SW	ACC SW signal/ON or OFF	ON: Ignition key is in ACC, ON or START position OFF: Ignition key is in OFF position	-
   IG SW	IG SW signal/ON or OFF	ON: Ignition key is in ON or START position OFF: Ignition key is in OFF or ACC position	-

NG	Go to step 2

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2. INSPECT FUSE

1. Inspect the ECU-ACC fuse, ECU-IG No.1 fuse and AM1 fuse in the instrument panel junction block assembly.

   Resistance:

   Below 1 Ω
   

NG	REPLACE FUSE

OK

3. INSPECT RELAY

1. Inspect ACC relay continuity.

   1. Remove the ACC relay from the instrument panel J/B.

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

      Resistance:

      Tester connection	Condition	Specified resistance
      3 - 5	Always	10 kΩ or higher
      3 - 5	Apply B+ between the terminal 1 and 2	Below 1 Ω

2. Inspect IG1 relay continuity.

   1. Remove the IG1 relay from the instrument panel J/B.

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

      Resistance:

      Tester connection	Condition	Specified resistance
      3 - 5	Always	10 kΩ or higher
      3 - 5	Apply B+ between the terminal 1 and 2	Below 1 Ω

NG	REPLACE RELAY

OK

4. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (ACC, IG)

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

   Voltage:

   Tester connection	Condition	Specified condition
   1I-3 - Body ground	Ignition switch is OFF → ACC, ON	Below 1 V → 10 to 14 V
   1I-9 - Body ground	Ignition switch is OFF → ON	Below 1 V → 10 to 14 V

NG	Go to step 5

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

5. INSPECT JUNCTION BLOCK NO. 2 (POWER SOURCE CIRCUIT)

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

   Voltage:

   Tester connection	Condition	Specified condition
   1A-1 - Body ground	Always	10 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

OK

6. INSPECT INSTRUMENT PANEL J/B ASSEMBLY

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

   Voltage:

   Tester connection	Condition	Specified condition
   1I-4 - Body ground	Always	10 to 14 V

NG	REPLACE INSTRUMENT PANEL J/B ASSEMBLY

OK

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

1. Disconnect the 1F connector from the instrument panel junction block assembly.

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

   Resistance:

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

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8. INSPECT IGNITION SWITCH

1. Disconnect the ignition switch connector.

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

   Resistance:

   Tester connection	Condition	Specified condition
   2 - 3	Ignition switch OFF	10 kΩ or higher
   2 - 4	Ignition switch OFF	10 kΩ or higher
   2 - 3	Ignition switch ACC	Below 1 Ω
   2 - 4	Ignition switch ON	Below 1 Ω

NG	REPLACE IGNITION SWITCH

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - IGNITION SWITCH)