Why is my Tire Pressure Monitoring System (TPMS) light coming on? Here’s Why
By Greg Burchette
If your TPMS (tire
pressure monitoring system) warning light goes on during a cold snap, it may
not mean your tire has a leak.
Tire pressure can
decrease about 1 PSI (pound per square inch) for every 10 degrees the
temperature drops. It’s not that more air is escaping your tires, but rather
the air inside the tire condenses, taking up less space when it’s cold. It’s
similar to how a cake, just out of the oven, flattens out a bit as it cools.
Tires also lose about 1
PSI per month just from seepage of air around the edge of the rim and through
the tread itself.
These two factors
combined can cause the air pressure in a tire to go 25 percent below the
recommended fill pressure. This is what triggers the sensing transmitters
inside your tires to illuminate your TPMS dash light. Whenever your
TPMS light comes on, have your air checked and bring your tires up to the
proper pressure.
Winter Tire Pressure
Temperature changes
outside affect your tire pressure. If it gets up to 45 degrees by day and drops
to 15 degrees at night, your tire pressure will vary 3 PSI, not counting normal
air loss. This is why it’s not unusual to have the low-pressure indicator light
go on first thing in the morning, since it’s usually coldest overnight.
The light may shut off on
its own after you drive 20 minutes or so, as the air in your tires warms and
expands and proper inflation level stabilizes.
Regardless, you
should get your air
checked right away. The TPMS light means your tires are at
least 25 percent below the proper air pressure. This is a safety risk,
especially if you’re carrying a load close to your vehicle’s max capacity.
There’s a greater chance of tire failure, compromised handling and increased
wear and tear on your tires. Your engine has to work harder to keep speed and our
gas mileage will go down.
When you top off your
tires, the TPMS light will go off as the tire regains the proper pressure.
Note: If the warning
light is flashing, this is a problem with the vehicle’s TPMS system, not your
tires, and you should have your car looked at..
One More Reason Your TPMS Light May Go On
Your TPMS light may flash
if your vehicle’s onboard computer can’t detect the sensor because you’re using
a spare tire. They typically don’t have TPMS sensors.
How to Get Winter Tire Pressure Right
Once a month, have your
pressure checked when the tires are cold (meaning the car is parked outside and
hasn’t been driven in four hours) and inflate them to what’s indicated on your
placard located on the inside of your car door.
If you have any questions about TPMS please do not hesitate to
call us at Bridgewater Motorworks at 908.218.9100.
By Greg Burchette If your TPMS (tire pressure monitoring system) warning light goes on during a cold snap, it may not mean your tire has a leak. Tire pressure can decrease about 1 PSI (pound per square inch) for every 10 degrees the temperature drops. It’s not that more air is escaping your tires, but…
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