Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Problem Symptoms Table

Theft deterrent system cannot be set

Refer to "Security Indicator Light Does not Blink"

Refer to "Door Courtesy Switch Circuit"

Refer to "Back Door Courtesy Switch Circuit"

Front door lock with motor assembly

Rear door lock assembly

Back door lock assembly

Refer to "Engine Hood Courtesy Switch Circuit"

Security indicator light does not blink when theft deterrent system is set

Refer to "Security Indicator Light Does not Blink"

Alarm sounding state cannot be canceled when engine switch is turned on (IG)

Refer to "Smart Access System with Push-button Start (for Start Function)"

Certification ECU (Smart key ECU assembly)

-

If the symptom(s) still occur after the above areas are inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Theft deterrent system can be set even when door is open

Refer to "Door Courtesy Switch Circuit"

Refer to "Back Door Courtesy Switch Circuit"

If the symptom(s) still occur after the above areas are inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Theft deterrent system can be set even when engine hood is open

Refer to "Engine Hood Courtesy Switch Circuit"

Vehicle horns do not sound while theft deterrent system is in alarm sounding state

Refer to "Horn Circuit"

Low beams do not blink while theft deterrent system is in alarm sounding state

Refer to "Lighting System (w/ Headlight Leveling)"*3

Refer to "Low Beam Headlight Circuit"*4

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Taillights do not blink while theft deterrent system is in alarm sounding state

Refer to "Taillight Relay Circuit"

*3

*4

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Hazard warning lights do not flash while theft deterrent system is in alarm sounding state

Combination meter assembly

-

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Interior lights does not light up while theft deterrent system is in alarm sounding state

Refer to "Interior Light Circuit"

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Security horn does not sound while theft deterrent system is in alarm sounding state*1

Refer to "Security Horn Circuit"

Theft warning siren does not sound while theft deterrent system is in warning operation*2

Refer to "Theft Warning Siren Circuit"

Low beams blink even when theft deterrent system is not set

Refer to "Lighting System (w/ Headlight Leveling)"*3

Refer to "Low Beam Headlight Circuit"*4

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Taillights blink even when theft deterrent system is not set

Refer to "Taillight Relay Circuit"

*3

*4

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Hazard warning lights flash even when theft deterrent system is not set

Combination meter assembly

-

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

Interiors light comes on even when theft deterrent system is not set

Refer to "Interior Light Circuit"

If the symptom(s) still occur after the above area is inspected and proved to be normal, replace the main body ECU (multiplex network body ECU)

The vehicle does not enter the alarm sounding state as the battery is reconnected

Check the battery

Refer to "Power Source Circuit"