Resume Control
WARNING: This page is about a different car, the 2002 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
After canceling the cruise control (except when the CRUISE switch is off) if the vehicle speed is above the minimum speed limit (approximately 25 mph, 40 km/h) operating the RES/ACC switch from OFF to ON will cause the system to accelerate to resume the vehicle speed before manual cancellation.