Circuit Description
WARNING: This page is about a different car, the 2004 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent ECU monitors a signal of vehicle's speed transmitted multiply from the meter ECU, and it will drive each door lock motor when any of the doors is in the unlocked state with the vehicle's speed at approximately 20 km/h (13 mph).
NOTE:
The electrical door lock system has a function with large-scale body multiplex communication. First of all, inspect the communication function and check that no malfunction exists in the troubleshooting.