Toyota CH-R Service Manual: IG Signal Circuit

DESCRIPTION

This circuit detects the ignition switch ON or off condition, and sends it to the main body ECU (multiplex network body ECU).

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1.	CHECK FOR DTC (SMART KEY SYSTEM (for Start Function))

HINT:

If the vehicle is not equipped with an smart key system, proceed to next step (A).

(a) Clear the DTCs.

Click here

Body Electrical > Power Source Control > Clear DTCs

(b) Check for DTCs.

Click here

Body Electrical > Power Source Control > Trouble Codes

Result	Proceed to
Smart Key System (for Start Function) DTCs are not output	A
Smart Key System (for Start Function) DTCs are output	B

B

GO TO SMART KEY SYSTEM (for Start Function)

A

2.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Main Body > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
IG SW	Ignition switch ON signal	ON or OFF	ON: Ignition switch on OFF: Ignition switch off	-

Body Electrical > Main Body > Data List

Tester Display
IG SW

OK:

Normal conditions listed above are displayed.

Result	Proceed to
OK	A
NG	B

A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

B

3.	CHECK HARNESS AND CONNECTOR (BATTERY POWER SOURCE - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the 3K instrument panel junction block assembly connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
3K-1 - Body ground	Always	11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.	CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Remove the instrument panel junction block assembly.

Click here

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

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
3D-30 - 3A-15	Ignition switch off	Below 1 Ω
3D-30 or 3A-15 - Body ground	Ignition switch off	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.	INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly.

Click here

(b) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

Click here

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

*a

Component without harness connected (Instrument Panel Junction Block Assembly)

-

-

Standard Resistance:

Tester Connection	Condition	Specified Condition
3K-1 - 3D-30	Battery not connected to 3A-17 and 3D-3	10 kΩ or higher
3K-1 - 3D-30	Battery positive (+) → 3A-17 Battery negative (-) → 3D-3	Below 1 Ω
3A-15 - MB-32 (IG)	Always	Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY