As a car owner, all those lights on the dash can be highly frustrating. Not all the alerts are easy to decipher, and when the car is still running fine, it’s tempting to ignore a warning light.
We think it’s important to remind you that the alerts and warning lights are there for a reason. Not only do they provide you with the security of knowing that something might be brewing under the hood, they also save time when it comes to diagnosing a problem.
One of the least understood but most important dashboard lights is the “low tire pressure light.” Do you know what your low tire pressure tire light looks like and what to do if it comes on?
What is TPMS?
The low tire pressure light comes on when your vehicle detects that the air pressure in one or more of your tires has dropped below a pre-set minimum. This is the work of your Tire Pressuring Monitoring System (TPMS), which is required by law on all cars built after September 2007.
On most cars, each tire has its own pressure sensor, which sends an alert to the monitoring computer if the pressure is too low. Other vehicles use the wheel speed sensors in the anti-lock braking system (ABS) to determine if a tire is low: A tire that’s low on pressure will have a smaller outer diameter and will require more revolutions than a tire that’s at the right pressure.
Since 2015, we’ve actually seen more car makers switch to the ABS and wheel speed method of monitoring. This is because, in the other set up, the TPMS sensors built into each wheel are battery operated, and the batteries fail after several years in service. Unfortunately, the batteries aren’t replaceable, which means each sensor has to be replaced. This leads to a costly and, often unpopular, repair.
What Should You Do if Your Low Tire Pressure Light Comes On?
If a light comes on your dashboard, it is important not to ignore it. We first recommend using your owner’s manual to see what the warning light is for or contacting My Mechanic for help.
When it’s your low tire pressure warning, we recommend checking the tire pressure on each tire or stopping by to have us check it. If your…
- Tires are at about the same psi level but beneath the specification or if you have one that’s just 2-4 psi low, we recommend adding air to the tires, turning the light off, and continuing to monitor. If the light comes back on within a month and the same tire(s) needs more air, there’s likely a puncture or slow leak that needs attention. If the light stays off, you shouldn’t need to do anything further.
- Tire pressure is within the specified range on all four tires, reset the light and monitor. If it comes on again within a short period of time, we recommend scheduling an appointment with My Mechanic so we can make sure the system is operating as intended.
- TPMS light is flashing or blinking, it usually means there’s an electronic or mechanical failure with the system. Again, we recommend scheduling an appointment so we can see what’s happening.
What Happens if Your Tire Pressure is Too Low?
Why all this fuss about tire pressure? It comes down to safety and fuel economy. If your tire pressures are too low, it can lead to a host of problems such as:
- You’ll wear out the tires prematurely, and buying new tires these days is a costly undertaking.
- Your fuel economy will drop, wasting gas and costing you more at the pump.
- You’ll have an increased risk of a blow-out, which can lead to a serious accident.
- You won’t be stop or steer the vehicle as well, increasing the risk of an accident.
How Do Changes in Weather Affect Tire Pressure?
There will be times when your low tire pressure light will come on even when you don’t have a nail in the tire or some other puncture. Sudden changes in air temperature or a series of changes in air temperature can actually lower your tire pressure. This is because tire pressure drops about 1 psi for for every 10-degree Fahrenheit drop in air temperature.
You may see a warning light as summer fades away and winter descends or if you have a vehicle that sits a lot.
Don’t Ignore a Low Tire Pressure Warning
The low tire pressure light might seem like an inconvenience, but it is there to keep you safe and to reduce your fuel consumption. Because most tires are now “low profile,” it is nearly impossible to discern when your tire is low just by “eyeing it.” In some cases, your tire might be as much as 20 percent lower than it should be, and there would be no way to visibly see it.
So if your low tire pressure light comes on, don’t ignore it. After all, a whole lot is riding on those tires! And as always, if you have any questions, we are here to help!
