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 | .gif) | GO TO HORN SYSTEM |
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| 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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Theft Warning Siren Circuit
DESCRIPTION The theft warning siren has an internal battery. If the vehicle auxiliary battery cable is disconnected or any of the communication lines are open, the theft warning siren detects this and
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Installation
INSTALLATION CAUTION / NOTICE / HINT NOTICE:
Do not replace the spiral cable with the battery connected and the power switch on (IG).
Do not rotate the spiral cable when the following conditions are met: 1) The steering wheel is removed, 2) the battery is connected, and 3) the power switch on (
Terminals Of Ecu
TERMINALS OF ECU CLEARANCE WARNING ECU ASSEMBLY (a) Disconnect the I20 clearance warning ECU assembly connector. (b) Measure the voltage and resistance on the wire harness side connector according to the value(s) in the table below. Terminal No. (Symbol) Wiring Color Terminal Description C
