why is my tire sensor light flashing

how do i do the retrain routine

Service information states to use a TPMS reset tool to excite the sensors. An alternative method that may work is to put the system into training mode and let air out of the tire(s) in order and listen for the horn to beep when the sensor reports. To put the system into training mode: The first step is with the key off press and release the brake pedal. Now cycle the key on /off three times staying on the third time. Touch the brake pedal again. Turn the key off. Cycle the key on/off another three times and again stay on after the third time. If you got it to enter training mode you will hear the horn beep once and the TPMS light will start flashing. Now you can go to the left front sensor and either use the TPMS tool to activate the sensor, or try letting air out which should cause the sensor to transmit. If it works you will hear the horn beep one time. Now it's time to move to the right front wheel and do the same. Then the right rear, and then the left rear. Once al four sensors have trained you will hear a double beep from the horn and the light will stop flashing and go out. If the lamp stays on, and especially if the horn doesn't beep when attempting to train one or more of the sensors then you have likely located a failed sensor. There is actually even more to this depending on identifying any faults, but if the system is fully functional this should get you through. Remember to reset all of your tire pressures to spec after training the system.