Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: System Description

Electrical key transmitter sub-assembly

Electrical key and tire pressure monitoring system receiver assembly

Receives weak radio waves from the electrical key transmitter sub-assembly and sends them to the certification ECU (smart key ECU assembly).

Certification ECU (Smart key ECU assembly)

Sends wireless door lock control signals in response to the code data from the electrical key and tire pressure monitoring system receiver assembly and signals from each ECU.

All door lock

Pressing the lock switch locks all of the doors.

All door unlock

(Unlock 2 operation)

Pressing the unlock switch twice within 5 seconds unlocks all of the doors after the driver door is unlocked.

Back door open

Pressing the back door open switch of the electrical key transmitter sub-assembly for longer than approximately 0.8 seconds opens the back door.

Automatic lock

If none of the doors is opened within 60 seconds after they are unlocked by the wireless door lock control, all of the doors will lock again automatically.

Answer-back (Hazard warning light)

Answer-back (Wireless door lock buzzer)

Panic alarm

Pressing the panic switch of the electrical key transmitter sub-assembly for longer than approximately 0.8 seconds causes the following alarms to activate:

While the panic alarm is operating, pressing any switch of the electrical key transmitter sub-assembly cancels the alarm operation.

Door ajar warning

The buzzer sounds for 5 seconds continuously when the lock switch is pressed when any of the doors are ajar. The buzzer stops when all of the doors are closed or the unlock switch is pressed.

Illuminated entry

When all of the doors are locked, pressing the unlock switch causes the interior lights to come on simultaneously with the unlock operation.

Self-diagnostic mode

If the electrical key and tire pressure monitoring system receiver assembly receives normal radio waves from the electrical key transmitter sub-assembly when the system is in diagnostic mode, it sounds the wireless door lock buzzer in a normal pattern that corresponds to the function of each switch.