Tire Air Pressure

[SusanOfWoodbury]

I moved to TV 2 years ago we it brand new tires, on my car. I have has a, problem with tire pressure
since I have moved. The tire pressure light keeps coming on?? I have a company put air in the tires
But, the light does not.out????
Any help would be appreciated

[Bogie Shooter]

Could be a bad sensor?

[villagetinker]

Have you had the tire(s) checked for slow leaks? If you are in an area with new construction, nails and staples can be a problem. Depending on the make of your vehicle, it may use sensors in the tires, or it might use the ABS system (like my wife's VW). We had problems with my wife's car when the tires were rotated, NO leaks, but the light came on a couple of times until we figured out how to reset the system.
Hope this helps.

[Mikeod]

Check the spare tire.

[villagetinker]

mikeod,

Good point I do recall some cars had a monitor on the spare, when cars had spare tires..........

[SusanOfWoodbury]

Thanks for the suggestions

[Sparty6971]

If you have a car with the 60psi doughnut spare under the car (like most minivans) almost no one, including the dealers, will check the pressure in them. It is a little time-consuming for places to drag the tire out, check & air it up, then get it back under the car and snugged up. So most oil change places and even the dealers don't check it. Not sure if those have the pressure sensor but if it does, that is quite likely why the pressure lite stays on. If it doesn't have a pressure sensor, I suggest you have the pressure of the spare checked any way - after a couple of years it may well be down below 30psi and will be dangerously close to failure just when you need it.

[BarryRX]

We have a Hyundai Sonata. Every once in awhile the air pressure light comes on, but when I check the pressure it is ok. Never thought to check the spare. Will give it a try.

[zcaveman]

Do you have the green caps on your tires? I was told that the green caps mean that you have nitrogen in your tires. If you offset them with air from a gas station, it mixes with the nitrogen and causes problems.

My first Hyundai had the green caps and I added air when the light came on and kept having problems. At service the told he about mixing the air. My new Hyundai has plain caps and I have not had a problem.

Z

[ditka41]

My Honda CRV's pressure warning light stays on, even after tire repair, until the car exceeds 30 MPH. At that time, it resets itself and the light does not show again unless there is truly a low pressure in one of the tires.

[tuccillo]

There may be something else going on. Regular, old air is 78% nitrogen. I have added air to tires originally filled with (presumably) 100% nitrogen and not had any issues.

Do you have the green caps on your tires? I was told that the green caps mean that you have nitrogen in your tires. If you offset them with air from a gas station, it mixes with the nitrogen and causes problems.

My first Hyundai had the green caps and I added air when the light came on and kept having problems. At service the told he about mixing the air. My new Hyundai has plain caps and I have not had a problem.

Z

[Aandjmassage]

Are light came on and said check right front tire put air in front tires light stayed on. Two days later put air in back tires light went out.

[TunaFish]

My Toyota has tire pressure sensors inside the tires attached to the value stem. They do go bad. I had to take it to dealer to find out which tire sensor was bad. Had it replaced.

[gustavo]

There may be something else going on. Regular, old air is 78% nitrogen. I have added air to tires originally filled with (presumably) 100% nitrogen and not had any issues.


The reason the N2 fill is better is because the pressure for 100% N2 has less sensitivity to temperature than an air fill. That being said, the only issue from adding air to an N2 fill is that the mix will be less than 100% N2 but not that much less unless you deflate the whole tire and refill it with air as the air is 78% N2 as stated above. So the air/N2 mix is not as good as the N2 only but way better than the 100% air tire, as related to temperature sensitivity.

With respect to the sensor not resetting after a fill: They are built with a fixed hysteresis on the alarm switch mechanism. If the light is off with 33 psi but then comes on at 32 psi and stays on at 31 psi and then you fill it to 33 psi the light should still be on. You have to fill it to a value above the built in hysteresis limit like 35 or 36 psi. Then when it resets you can bleed a few psi down to the optimal pressure (for my example 33 psi).