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TPMS warning icon

Tire Pressure Sensor Monitor (TPMS) Warning indicator

The acronym stands for TIRE PRESSURE MONITOR SYSTEM and it monitors (yep you got) tire pressure, letting you know when one or more of your automobile’s  tires become underinflated.

One day, while driving, a new thing started to blink on my dashboard. It’s was a strange looking symbol and I have no idea what it is but it looked BAD.

That is what I thought the first time I ever saw the TPMS warning indicator, pictured above. If you really look hard you can see that the original icon inventor, (who IS that person?) tried to make it look like a tire with an exclamation point in it. The exclamation I got, the tire I did not.  After the TREAD ACT was created it became mandatory for all light motor vehicles (under 10,000 lbs) to have TPMS sensors installed to alert drivers when their tires become under inflated.

When my TPMS Cluster light turned on and I was told what it was, a visual walk around inspection of my tires did not immediately reveal that I had a low tire, but when I checked it with a gauge it was low! So it worked!!

How does TPMS Work?

Sensors that are placed either inside your tire or out on the inside rim. When your tire pressure gets below a certain threshold the sensor sends a signal to your automobiles computer and the flashing icon starts blinking on your dashboard.

There is two types of TPMS Sensors- Direct and Indirect

Direct TPMS- Sensors are placed directly on or in your tire and physically measure each individual tire’s pressure. It then reports any under inflation on any of the tires, or all of them, back to the instrument panel. With the Direct system you do have to worry about the sensors batteries going dead or the sensor being affected by environment  It also means that you just can’t rotate your tires because the sensor’s are tire specific.

Indirect TPMS- There are no sensors used for Indirect TPMS and this method does not measure actual air pressure. It relies on wheel rotational speed and other methods. For example, an under inflated tire will rotate differently than an properly inflated one.  This is measured through wheel speed sensors of the ABS/ESC systems. Once the driver checks all the pressures and determines they are good he needs to reset the system by pressing a button or using the on board computer.


Benefits of Tire Pressure Monitor Sensors

Save yourself the aggrevation of a flat tire. Pay attention when your TPMS sensor light turns on.

Save yourself the aggravation of a flat tire. Pay attention when your TPMS sensor light turns on.









Under inflated tires not only wear out sooner they can be dangerous so anything that will warn us when we need to put air into our tires is a huge benefit.

Properly inflated tires:

  • Will  last longer
  • Will give you better gas mileage
  •  Provide greater stability, handling and braking which will be safer for the driver, and passengers, other vehicles on the road.

So pay attention to your dashboard and keep your tires inflated.  

General Motors Tire Pressure Monitor Sensor Activation Tool

General Motors Tire Pressure Monitor Sensor Activation Tool

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