Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: IG Signal Circuit

DESCRIPTION

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

PROCEDURE

1.

CHECK FOR DTC (SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function))

(a) Clear the DTCs.

Click here

Body Electrical > Smart Access > Clear DTCs

(b) Check for DTCs.

Click here

Body Electrical > Smart Access > Trouble Codes

Result

Proceed to

Smart Access System with Push-button Start (for Start Function) DTCs are not output

A

Smart Access System with Push-button Start (for Start Function) DTCs are output

B

B

GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function)

A

2.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(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

Engine switch on (IG) signal

ON or OFF

ON: Engine switch on (IG)

OFF: Engine switch off

-

Body Electrical > Main Body > Data List

Tester Display

IG SW

OK:

Normal conditions listed above are displayed.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

3.

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

(a) Disconnect the 2E 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

2E-1 - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.

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

2E-1 - MB-32 (IG)

Battery not connected to 2A-17 and 2B-3

10 kΩ or higher

2E-1 - MB-32 (IG)

Battery positive (+) → 2A-17

Battery negative (-) → 2B-3

Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    Data List / Active Test
    DATA LIST / ACTIVE TEST DATA LIST NOTICE: In the following table, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether ...

    ACC Signal Circuit
    DESCRIPTION This circuit detects the engine switch on (ACC) or off condition, and sends it to the main body ECU (multiplex network body ECU). WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Occupant Classification System: Data List / Active Test
    DATA LIST / ACTIVE TEST DATA LIST HINT: Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be dis ...

    Lexus RX (RX 350L, RX450h) 2016-2025 Owners Manual > Child safety: Riding with children
    Observe the following precautions when children are in the vehicle. Use a child restraint system appropriate for the child, until the child becomes large enough to properly wear the vehicle's seat belt. It is recommended that children sit in the rear seats to avoid accidental contact wi ...

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual

    © 2025 Copyright www.lexusrx.net
    0.0143