Lexus NX: 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 horn to sound at intervals of 0.4 seconds.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

NOTICE:

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

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PROCEDURE

1.

CHECK HORNS OPERATION

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

Horns do not sound

GO TO HORN SYSTEM

Horns sound

2.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Remove the instrument panel junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

4B-49 - A-28 (HORN)

Always

Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

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 Components

COMPONENTS ILLUSTRATION *1 DECK FLOOR BOX LH *2 NO. 3 DECK BOARD SUB-ASSEMBLY *3 REAR DECK FLOOR BOX *4 NEGATIVE AUXILIARY BATTERY TERMINAL N*m (kgf*cm, ft.*lbf): Specified torque - - ILLUSTRATION *1 BATTERY SERVICE HOLE COVER *2 HYBRID BATTERY SERVICE PLU

 Parts Location

PARTS LOCATION ILLUSTRATION *A w/ Seat Memory -   *1 FRONT POWER SEAT SWITCH LH *2 SEAT MEMORY SWITCH *3 TILT AND TELESCOPIC SWITCH *4 ELECTRIC POWER STEERING COLUMN SUB-ASSEMBLY - MULTIPLEX TILT AND TELESCOPIC ECU - TILT MOTOR - TELESCOPIC MOTOR *5 NO. 2 ENGIN

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