Lexus RX (RX 350L, RX450h) 2016-2025 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.
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- 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 | .gif) | GO TO HORN SYSTEM |
|
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| 2. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
(a) Remove the main body ECU (multiplex network body ECU).
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| *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 |
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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