Did you try retraining the system?
Make sure all your tires are at the correct pressure.
Turn the ignition ON (do not start engine).
Put the handbrake ON.
Hold the RESET button until the light flashes 3 times.
The retrain procedure is not complete until the vehicle is driver over 19mph or faster for an hour. During this time, the TMPS system may not be able to detect a low tire, so make sure all tires are at the correct pressure before you start.