The first radar (instead of previous lidar) sensor on a Lexus sedan allowed the new Dynamic RADAR Cruise Control to work in any weather conditions. The millimeter-wave radar technology also enabled the first Pre-Collision System (PCS) on a Lexus sedan (with partial autonomous braking only on the Japanese market Toyota Celsior version). A "low-speed tracking mode" was added in 2004. The low-speed tracking mode was a second mode that would warn the driver if the car ahead stopped and provide braking; it could stop the car but then deactivated.