Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: Horn Circuit

DESCRIPTION

When the theft deterrent system is switched from the armed state to the alarm sounding state, the main body ECU (multiplex network body ECU) transmits a signal to cause the horns to sound at intervals of 0.4 seconds.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

INSPECT HORNS

(a) Press the horn switch and check if the horns sound.

Result

Proceed to

Horns sound

A

Horns do not sound

B

B

GO TO HORN SYSTEM

A

2.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the main body ECU (multiplex network body ECU).

Click here

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

(b) Disconnect the 2C instrument panel junction block assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2C-27 - MB-28 (HORN)

Always

Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    Engine Hood Courtesy Switch Circuit
    DESCRIPTION The engine hood courtesy switch is built into the hood lock assembly. This switch turns on when the engine hood is closed and turns off when the engine hood is opened. WIRING DIAGRAM CAUT ...

    Security Horn Circuit
    DESCRIPTION When the theft deterrent system is switched from the armed state to the alarm sounding state, the main body ECU (multiplex network body ECU) transmits a signal to cause the security horn a ...

    Other materials:

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Rear Combination Light Assembly (w/o Rear No. 2 Seat): Disassembly
    DISASSEMBLY CAUTION / NOTICE / HINT HINT: Use the same procedure for the RH side and LH side. The following procedure is for the LH side. PROCEDURE 1. REMOVE REAR COMBINATION LIGHT CAP (for LED Type Turn Signal Light) (a) for TMMC Made: (1) Remove the rear combination light cap. HINT: Use ...

    Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual > Rear No. 1 Seat Outer Belt Assembly: Inspection
    INSPECTION PROCEDURE 1. INSPECT REAR NO. 1 SEAT OUTER BELT ASSEMBLY (a) Before installing the rear No. 1 seat outer belt assembly, check the ELR function. NOTICE: Do not disassemble the retractor. (1) When the inclination of the retractor is less than 15°, check that the belt can be pulled from ...

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

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

    © 2026 Copyright www.lexusrx.net
    0.0116