Adaptive Cruise Control problems of the 2021 Toyota Corolla

Coolant bypass valve needs replaced. Car states 'engine maintenance required visit dealer. '.

My 2021 Toyota Corolla, with 3000 miles and less than a year on it, is repeatedly exhibiting a "check gas cap" warning message followed a day or two later by a "check engine, visit your dealer" warning. This has happened twice. I have returned to the dealer once to have the system reset, after which the same sequence of warning messages recurred. This message wipes out my dashboard display and keeps me from using my cruise control and radar distancing feature. I have not yet determined what other safety features are neutralized by this recurring malfunction. Emmett r. Vick.

The vehicle does not keep the set speed. Ex. When cruise is set to 65, the vehicle will remain at 64 never making it to 65. This occurs with clear road ahead and no traffic.

The problem seems to occur when activating the full-speed range dynamic radar cruise control (drcc) feature, as detailed next. During a recent trip, the car behaved in a potentially dangerous, life-threatening manner when the drcc function was activated. Specifically, the car seems to increase the rpm of the engine to dangerous levels when going down a slope even if there is a speed limit set using the cruise control. In other words, the car does not change gear properly to keep the rpm in normal ranges. The engine’s rpm getting close, entering the red zone indicated by the rpm tachometer, and staying there even for seconds may cause an engine explosion which at highway speeds can be extremely dangerous for the passengers and other nearby vehicles on the road.