Tire pressure monitoring system does not work as designed. For the last 24,000 miles the system has not worked as intended with multiple failures of multiple types. Initial failures clustered around the pressure in the spare being set at a different pressure than the drive tires. Secondary failures clustered around the fact that the drive tires heated during operation and were subsequently at a different temperature and thus pressure than the spare. Inclusion of the monitor on the spare seems a design flaw. If the spare is needed than their will already be a tire on/in the vehicle signaling to the computer that a pressure event has occurred. Since the system does not signal which tire is low the information from the spare can only be a problem. Third the tire pressure monitor light started blinking. Diagnosis was a failed tpm sensor. Consultation at Toyota dealership with three master mechanics and a service manager established this as a chronic problem in Toyota, especially if a tire is ever replaced. Their professional recommendation was a piece of black electrical tape over the light on the dash. They did offer to get the replacement sensor in. Even with the VIN they were unable to ascertain what part it is though. Toyota has two different sensors for this vehicle and there is apparently no way to determine the proper part until disassembly. Having a dash warning light on for thousands of miles desensitizes drives to important lights when they illuminate. If Toyota is unable to produce a system that works properly they should provide some way for dealers or owners to disable the system. Unfortunately the dealership indicates that no such work around is available.

- King George, VA, USA