Tire Pressure Monitoring Problems
by Pat Goss
One of the most important parts of having a safe car is having proper tire pressure. That means you need a good high quality tire-pressure gauge, and you need to check the pressure in your tires at least once a month. Now here’s where you may make a mistake: you know lots of folks look at the side wall of the tire - well that doesn’t get it. Here’s where you look, at the decal that’s attached to the body of the car. That tells you the proper pressure for the car, not what’s on the side of the tire.
Here’s something else: tire pressure caps. These actually work. They turn red, green, or yellow depending on tire pressure, red meaning danger and green meaning it’s okay, but you have to be careful with these if you scuff a curb. You could wind up with a flat tire because these are the primary seal.
The other problem here is the only ones I’ve seen are either calibrated to 32 P-S-I or 35 P-S-I and there aren’t too many cars on the road that require those two specific pressures, so use your judgment there.
If you have a late model car, there’s a good possibility it may be equipped with a tire pressure monitoring system, T-P-M-S. All 2008 cars and light trucks will have these systems. They use sensors inside the wheels like this one which is a valve-stem type sensor. It goes into the wheel, and the valve stem is where you’re going to check and add air to the tire. A second type attaches to a band or strap or clamp that goes around the center of the tire. They both do an excellent job but you have to be extremely careful in selecting the shop that does your tire work. Reason being, if they take the tires off wrong or put them back on wrong, they can come right across that sensor and crush it.
Okay, so now they have to know how to change them, and they also have to have one of these. This is a tire pressure monitoring system reset tool. Many times when you rotate tires, these systems are sensitive to what corner of the car the tire is on. This tool fits over the valve stem and the technician programs it and tells the tool what to do. It in turn relays this information to the computer on the car, and the car now knows where that tire is located and you don’t wind up with a warning light on the dash.
If you have a question or comment, write to me.
The address is MotorWeek, Owings Mills, MD, 21117.