Tire Pressure Monitoring System (TPMS)

Here are the basic facts and information you need to know about the TPMS  (Tire Pressure Monitoring System)on your vehicle:
Why TPMS?
The U.S. government mandated the use of TPMS on vehicles as part of the TREAD act. The act was created in response to the Firestone tire tread separation issue of the late 90's, which partly blames underinflated tires as the cause of blowouts (a defect that has killed at least 88 and injured 250 people, most of them in Ford Explorers) . All passenger vehicles under 10,000 pounds gross weight produced after September, 2007, are required to have the system.

What does it do?
Each wheel has a pressure sensor and transmitter located inside which is connected to the valve stem. The system monitors the pressure of the tires (some cars monitor the spare tire as well) and provides the driver a warning if any tire is underinflated.

Special Precautions:
- DO NOT use tire puncture sealant as it could damage the sensor.
- Removal of the OEM tires can damage the sensor. The sensor must be removed prior to dismounting the tire from the rim. There is a specific procedure for doing this and the dealer and tire shops familiar with TPMS systems should be able to do it properly.

The low tire pressure warning light in ON:
- Check the tire pressure using an accurate tire gauge and ensure they are inflated (check the sticker on the drivers side door jamb). The warning light should clear after driving for 5 minutes above 16 miles per hour.

- If the outdoor air temperature drops suddenly, the tire pressure will drop and may trigger the TPMS. Re-adjust the tire pressures.

The low tire pressure warning light blinks for one minute then stays ON:

- If you rotate or change tires, (sometimes even the spare tire), you may get the low tire pressure warning light. The vehicle performance should not be affected while the light is ON, assuming you don't have a flat tire. The light will go off  after driving for 5 minutes above 16 miles per hour.
- It is possible there is a malfunction in the system. Time to book a service appointment with your tire dealer to check things out.

What about tire rotation?
Tire rotation should not affect the sensors. In a worst case, you will get the blinking TPMS and may have to make a trip to automotive tire and repair dealer to clear the code.

There are two types of TPMS systems: Direct TPMS and Indirect TPMS.

Direct TPMS
Direct TPMS delivers real time tire pressure information to the driver of the vehicle - either via a gauge or a simple low pressure warning light. These systems employ physical pressure sensors inside each tire and a means of sending that information from inside the tire to the vehicle instrument cluster.

Indirect TPMS
Indirect TPMS measures the air pressure indirectly by monitoring individual wheel speeds and other signals available in the vehicle. Most indirect TPMS uses the fact that an under-inflated tire has a slightly smaller diameter than a correctly inflated tire and therefore has to rotate more times to cover a specific distance to detect under-inflation. Such TPMS can detect under-inflation in up to three tires simultaneously, but not in all four since the operating principle of these systems is to compare the different wheel speeds and if all four tires lose the same amount of air the relative change will be zero. 

Newer developments of indirect TPMS can also detect simultaneous under-inflation in all four tires thanks to vibration analysis of individual wheels or analysis of load shift effects during acceleration and/or cornering.

Indirect TPMS is cheap and easy to implement, since most modern vehicles already have wheel speed sensors for anti-lock braking systems and electronic stability control systems. The disadvantage is that they rely on the user resetting the system by pushing a "Calibration Button" when the tires are changed or re-inflated - forgetting to perform this initialization leads to potentially dangerous false or missing alerts. Another disadvantage of indirect TPMS is that if the Calibration Reset Button is pressed when one or more tires are under-inflated then the system accepts this under-inflation as normal and the driver will be unaware of potentially dangerous tire pressures.

At Hillside Tire and Service, we are your TPMS experts for all makes and models. Come in to any of our 5 Salt Lake Valley tire stores: Salt Lake City (Cottonwood Heights), West Valley City, West Jordan, Sandy or Draper for tires, alignments, brakes, and complete auto repair services.

We have tire discounts from manufacturer factory rebate specials going on right now. We also offer wheels, alignments, brakes, oil changes and complete auto repair services.