Vehicles with tire air pressure sensors

Check your owners manual. Often all 4 tires must be inflated to the same pressure (within a small percentage). Also, don't forget to check the spare (if the spare is equipped with a sensor).

TIRE PRESSURE MONITOR SYSTEM
The Tire Pressure Monitor System (TPMS) uses radio and sensor technology to check tire pressure levels. If your vehicle has this feature, sensors are mounted on each tire and wheel assembly, except the spare tire. The TPMS sensors monitor the air pressure in your vehicle's tires and transmit tire pressure readings to a receiver located in the vehicle.

The TPMS is designed to alert the driver, if a low tire pressure condition exists. This system also allows the driver to check tire pressure levels using the Driver Information Center (DIC).

When a low tire pressure condition is detected, the TPMS displays the "CHECK TIRE PRESSURE" warning message on the DIC, and at the same time illuminates the low tire pressure warning symbol.

You may notice, during cooler weather conditions, that the tire pressure monitor light, located on the instrument panel cluster, and the "CHECK TIRE PRESSURE" message will appear when the vehicle is first started and then turn off as you start to drive the vehicle. This could be an early indicator that the tire pressures are getting low and need to be inflated to the proper pressure.

Each tire, including the spare (if provided), should be checked monthly when cold and inflated to the inflation pressure recommended by the vehicle manufacturer on the vehicle placard or tire inflation pressure label. (If your vehicle has tires of a different size than the size indicated on the vehicle placard or tire inflation pressure label, you should determine the proper inflation pressure for those tires.)

As an added safety feature, your vehicle has been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pressure telltale when one or more of your tires is significantly under-inflated.

Accordingly, when the low tire pressure telltale illuminates, you should stop and check your tires as soon as possible, and inflate them to the proper pressure. Driving on a significantly under-inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling and stopping ability.

Please note that the TPMS is not a substitute for proper tire maintenance, and it is the driver's responsibility to maintain correct tire pressure, even if under-inflation has not reached the level to trigger illumination of the TPMS low tire pressure telltale.

The "CHECK TIRE PRESSURE" warning message and low tire pressure light (telltale) will appear at each ignition cycle until the tires are inflated to the correct inflation pressure.

The Tire and Loading Information label (tire information placard) shows the size of your vehicle's original tires and the correct inflation pressure for your vehicle's tires when they are cold.

Your vehicle's TPMS can alert you about a low tire pressure condition but it does not replace normal tire maintenance.

NOTICE: Do not use a tire sealant if your vehicle has Tire Pressure Monitors. The liquid sealant can damage the tire pressure monitor sensors.

RESETTING THE TPMS IDENTIFICATION CODES
Each TPMS sensor has a unique identification code. Any time you rotate your vehicle's tires or replace one or more of the TPMS sensors, the identification codes will need to be matched to the new tire/wheel position. Each tire/wheel position is matched to a sensor, by increasing or decreasing the tire's air pressure. The sensors are matched to the tire/wheel positions in the following order: LF TIRE (left front tire on the driver's side of the vehicle), RF TIRE (right front tire on the passengers side of the vehicle), RR TIRE (right rear tire on the passengers side of the vehicle), and LR TIRE (left rear tire on the driver's side of the vehicle).

You will have one minute to match the first tire/wheel position, and five minutes overall to match all four tire/wheel positions. If it takes longer than one minute, to match the first tire and wheel, or more than five minutes to match all four tire and wheel positions the matching process stops and you will need to start over.

The TPMS sensor matching process is outlined below:

1. Set the parking brake.
2. Turn the ignition switch to "RUN" with the engine off.
3. Turn the headlamp switch from "OFF" to the parking lamps setting four times within three seconds. A double horn chirp will sound and the TPMS low tire warning light will begin to flash. The double horn chirp and flashing TPMS warning light indicate that the TPMS matching process has started. The TPMS warning light should continue flashing throughout the matching procedure. The "SERVICE TIRE MONITOR" message will be displayed on the Driver Information Center (DIC).
4. Start with the driver's side front tire.
5. Remove the valve cap from the valve cap stem. Activate the TPMS sensor by increasing or decreasing the tire's air pressure for 10 seconds, then stop and listen for a single horn chirp. The single horn chirp should sound within 15 seconds, confirming that the sensor identification code has been matched to this tire and wheel position. If you do not hear the confirming single horn chirp, you will need to start over with Step 1. To let air-pressure out of a tire you can use the pointed end of the valve cap, a pencil-style air pressure gage or a key.
6. Proceed to the passenger's side front tire, and repeat the procedure in Step 5.
7. Proceed to the passenger's side rear tire, and repeat the procedure in Step 5.
8. Proceed to the driver's side rear tire, and repeat the procedure in Step 5.
9. After hearing the confirming horn chirp for the left rear tire, check to see if the TPMS warning light is still flashing. If it is, turn the ignition switch to LOCK to exit the sensor matching process. If the TPMS warning light is not flashing, the five minute time limit has passed and you will need to start the process over beginning with Step 1.
10. Set all four tires to the recommended air pressure level as indicated on the Tire and Loading Information label.
11. Put the valve caps back on the valve stems. The spare tire does not have a TPMS sensor. If you replace one of the road tires with the spare, the "CHECK TIRE PRESSURE" message will be displayed on the DIC screen. This message should go off once you re-install the road tire containing the TPMS sensor. The "SERVICE TIRE MONITOR" message is displayed when the TPMS is malfunctioning. One or more missing or inoperable TPMS sensors will cause the service tire monitor message to be displayed.

it means your tire pressure is below recomended pressure parramiters.
This system also moiters the spare!! so check it too!

Unless you had someone change the tires on the vehicle... and they broke off the tire pressure monitor... ( cost about $90 each!)

Tire pressure always changes...
when you drive your vehicle for a long period of time the tires' temperature goes up along with the
pressure in your tires, the molecules in the air inside your tires get excited (hot)
when your vehicle is immobile for a while your tires' temperature goes down along with the
pressure in your tires, the molecules in the air inside your tires get compacted (cold)
This is the best time to get a true PSI reading from your tires....
the recommended tire pressure on most tires should be set at 35PSI
But there might be a problem with your sensors, I work with TOYOTA their sensors are set up to
where when the PSI on your tires drops below the 35PSI, the tire pressure light would then
come on.
You should also check if your spare tire comes equipped with pressure sensors, which in most cases
they do, depending on the type of tire the PSI on spare tires will usually range from 35PSI- 80PSI
you can check your owners manual for this, or simply read the recommended PSI written on the
tire.

the tire in the trunk has a sensor also check the spare tire pressure , only the dealer will tell you this after you are charged to mount and balance the spare in the trunk..