Tuesday, October 25, 2011

What's with that weird light on my dash that looks like a butt? A brief discussion of the Tire Pressure Monitor System (TPMS)


     If your vehicle is a 2007 or newer (and a few older models as well), there is a good chance you have seen this symbol at some point during your ownership.  I have had many customers call, trying to describe it to me, and to ask what the heck it is, and what it is trying to tell them.  In all reality, what it is saying is "Check your tires!"  Since a certain SUV had issues with tires a number of years ago, the US Government issued a mandate that any vehicle built from 2007 forward would have an acceptable Tire Pressure Monitoring System.  They can be a nuisance, but they are there for the protection of the consumer.
     Living in Minnesota, with the changes in climate that we experience, this symbol has a tendency to show itself frequently during the Spring and the Fall seasons, when temperatures vary greatly from day to day.  When it gets colder, the air pressure in our tires will drop.  When it gets warmer, it increases.  This will often trigger the light you see above.  Other factors can cause a tire to become improperly inflated, including punctures from nails, screws and other debris.  It is worth while to have the tire checked out if you see this light.  Many of these can be repaired, saving you the cost of a tire replacement.
     Additionally, if you have recently purchased tires (especially if you did not get them from the dealership), it is possible that one of the sensors was broken during the tire mounting process.  Each tire has a pressure sensor in the valve stem that sends a signal to the "brain" of the system.  If a sensor is broken, it will read the pressure as "zero" and trigger the warning light.
     Since you won't know the cause when you see the indicator, the first thing you should do is take a few seconds, walk around your vehicle, and make sure you aren't driving on a flat.  With most of us having roadside assistance either through our manufacturer's warranty or through our auto insurance, if you see a flat, call for help and get it fixed before you move your vehicle.  You don't want to drive on a flat tire to the service station, ruining an expensive tire in the process.
     If all of the tires appear to be reasonably inflated (many of today's vehicles actually have a display in the trip computer that will tell you the pressure in each individual tire - check your owner's manual or call your salesman), then drive to a service station as soon as you can, and figure out which tire(s) is under/over inflated.  If this light is on, it is a situation that should be remedied as soon as possible, for the following reasons.
  1. If you actually do get a flat tire, and have been ignoring this indicator light for a period of time, the system will be unable to alert you further that you have a severe problem, and this could end up costing you money.
  2. An over or under inflated tire will have an effect on fuel economy, potentially costing you money
  3. A tire that is not at the proper inflation pressure will not wear evenly, and will shorten the life of the tire, costing you money.
  4. An over or under inflated tire will have an effect on ride and handling of your vehicle, effecting comfort and safety.
  5. An improperly inflated tire can pose a safety hazard, since the potential for tire failure is increased, endangering you and other drivers around you.
In short, while we know the Tire Pressure Monitor System warning light will never appear at a time that will be convenient, it's worth taking a few seconds to check it out.  It could save you money, and could even save a life.

Mike Bidwell
Mankato Motor Co.
www.mikebidwellcars.com
mikebidwellcars@gmail.com