Eddie spent 35 years in the automotive business with Honda. He is an ASE Certified Master Technician and has bruised knuckles to prove it.
So is the low tire pressure warning light on or is your TPMS light on? There is a difference, and the repair is very different depending on which warning light is on.
1. "Low Tire Pressure" Warning Light
If the low tire pressure warning light is on in your vehicle—the warning light with the icon of a tire with an exclamation point in the middle—the most likely cause is low tire pressure.
This warning light could be caused by any of these:
- an obstruction in the tire like a nail or screw;
- neglect (not setting tire pressures to manufacturer's specs at every oil change or every two months);
- or a seasonal drop in outdoor temperatures.
All tires, even tires in good condition, lose air for a number of reasons, but mostly because tires are porous. It's common to lose at least 1.5 psi per month naturally. But there is also scientific evidence that tire pressures drop with colder temperatures, so you could expect to lose at least 1 psi for every 10 degrees drop in temperature.
The NHTSA (National Highway Traffic Safety Administration) regulations state that the low tire pressure light indicator must come on when the tire pressure drops 25% below the listed recommended inflation pressure. Some manufacturers have stepped it up a notch and have set their tolerances to no more than a 20% drop in pressure before the light comes on, so check your owner's manual for more information.
What To Do If Your Low Tire Pressure Warning Light Comes on
If your low tire pressure warning light comes on, don't panic! Here are some steps you can take before you bring it into the garage;
1. Do a visual inspection of all your tires; make sure one is not flat. The spare tire counts too!
2. Check all your tires for proper inflation: about 32 psi in warm temperatures, 35 psi in cold temperatures.
3. If one tire has lower tire pressure then the other three, check it over for a nail or screw in the tire tread.
4. If you want to look for the leak, use a spray bottle with a water and dish soap mixture, spray the complete tire and rim, and then watch for bubbles.
Low Tire Pressure Means You Need to Put in More Air
Think of it like this: The low tire pressure light is like a low fuel light. When it's on, it means you need to put air in your tires, just like you would put more fuel in your car if it was low on fuel. Ultimately, it's the driver's responsibility to keep an eye on the vehicle's tire pressures, and having low tire pressure sensors in each tire will help you maintain proper inflation.
Why Is My Tire Pressure Low in the Winter?
Let's say you took your car in for an oil change in late August, and the temperature outside is a balmy 85 degree. The mechanic sets the tire pressures in your vehicle to 32 psi because it's recommended by the factory sticker in the driver's door jamb. Fast forward to late November or early December, and the temperature outside has dropped to 30 degrees (something that is very common in New England) and your low tire pressure light comes on.
You bring your vehicle in for its next oil change and the mechanic tells you that the tire pressures are all at just 24psi. Not only have you lost tires pressure naturally from being porous, but you have also lost tire pressure because of the 55-degree change in temperature. It's always best to set the tires' pressures to the "cold" inflation settings just before the cold temperatures set in. This will help prevent the pesky low tires pressure warning light from coming on so often.
The Nitrogen Work-Around
If you would like to take it one step further in trying to prevent the low tire pressure light from coming on, you could try filling your tires with nitrogen. A lot of dealerships and tire stores have had nitrogen filling stations installed since tire pressure monitoring systems have been implemented.
Filling your vehicle tires with nitrogen will reduce fluctuation in tire pressures because nitrogen has less water vapor in it than regular air does. It's not a perfect system or a permanent fix, but it does reduce the visits to the air pump or garage. It also comes with a price: usually around $100 for lifetime nitrogen fill, but ask your dealer for more information.
2. "TPMS" Warning Light
If the TPMS light is on, most likely you have a problem with the tire pressure monitoring system, for example a malfunctioning tire sensor. If all tire sensors are working properly, you may have to dig a little deeper to figure out what's causing the light to come on; you may even have a faulty control unit.
What to Do if Your TPMS Light Comes on
If the TPMS warning light is on, bring the car to the dealership, because there is something wrong with the tire pressure monitoring system.
Questions About TPMS or Your Low Tire Pressure Warning Light?
If you have any questions about your low tire pressure warning light, TPMS light, or nitrogen, feel free to ask and I will be glad to answer them as best as I can.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: Can my mechanic put air into a tire when there is still a nail in the tire?
Answer: It would be a better idea to remove the nail and plug the tire because the tire is just going to lose pressure again and you could possible destroy the tire.
Eddie Carrara (author) from New Hampshire on January 05, 2020:
Did you install new sensors in the wheels or does the car use the wheel bearing sensors?
Sharon on January 05, 2020:
Ihave changed from run flat to normal because of the uncomfortable tyres my tyre pressure light is staying on still and has been a problem for the garage but they cannot get it to reset what can they do .its got to go back again is it because of the change of wheels .Help its driving me mad .
Eddie Carrara (author) from New Hampshire on May 07, 2019:
If the light says "Tire Sensor Fault" the sensor has an issue (battery is low or damage to the sensor), not low tire pressure. You'll need to have a tire shop or garage test each sensor to find the problem.
Terry on May 06, 2019:
My girlfriend owns a 2012 Ford escape and the system saystire pressure sencer fault I've checked all the tires and thier fine pressure is good so what now
Eddie Carrara (author) from New Hampshire on December 17, 2018:
You may need to recalibrate the sensors via a switch in the vehicle, check your owners manual for the proper procedure, all cars are different.
Khaled H. on December 16, 2018:
Hey my tire pressure light came on. I filled the tires but light wont go off. What is going on with that? I have a 2014 jeep patriot
Eddie Carrara (author) from New Hampshire on March 22, 2018:
What is the year make and model of your vehicle? Sometimes there is a reset button or recalibration mode to reset the light.
Dianna Mendez on March 21, 2018:
Eddie, my tire pressure indicator remains on, even when our tires are filled to standard. What can we do?
Eddie Carrara (author) from New Hampshire on February 15, 2018:
Check your spare tire pressure, most likely the spare has low pressure. Let me know, thanks.
To Nguyen on February 14, 2018:
Hi. I just changed 4 tires on Toyota Highlander 2009 ,and the low tire pressure light on. I check pressure all tires ok, (light is not on before change tire).
Eddie Carrara (author) from New Hampshire on November 06, 2016:
I think what happened is the engine stalled, appearing as if you lost power, the oil light came on because your engine shut off, so I don't think you have a problem with the oil sensor, maybe your fuel pump is the problem. I recommend checking fuel pressure first. Keep me posted, thanks.
raycthe on November 05, 2016:
On a 1999 Ford Laser (or Mazda 323) 1.6 litre (four) auto, will the oil pressure sensor prevent ignition to the motor?
While driving at 100km on a country road (approx 3000 RPM) the car lost power and then the "oil light" appeared; the car would not restart.
The car was recently serviced about 400km ago with oil and filter (oil is in the engine) and as a seperate issue both coils/leads replaced.
When I checked the dipstick there is oil in the sump. I then opened the oil cap and there appears to be oil on the cams etc.
Will a faulty oil sensor cut the electrical circuit from the coils? There seems to be a 'charge' to the coil but nothing after the coil.
Thank you for your assistance with this matter.
Sent from my iPad
Eddie Carrara (author) from New Hampshire on October 06, 2014:
No, an oil change will not trigger the light, but if you rotate the tires on some vehicles, the light will come on and the system will need to be calibrated. Let me know if this helps Paul, thanks.
paulform on October 05, 2014:
Can this light be triggered by an oil change? This is the second time after having an oil change that a light has come on. The first time it happened a week or so after the change and the traction light came on. Took it to the dealership and all was fine and they reset it and the light went off. Next oil change - all was fine, went home, started the car up again and then the tire pressure light came on. It's a 2010 Toyota Corolla. I checked the pressure and it's fine - so I am wondering if it is possible that something is being triggered when they perform the oil change which makes these light come on.
Eddie Carrara (author) from New Hampshire on December 19, 2013:
I started writing here because I had a problem and couldn't find any good info on it, so I figured it out myself and wrote an article on it, I never thought anyone would read it or even find it in the search engines, then the lightbulb went off. Now I write to help people with what I know, the best part is, I meet people all over the world, who I can engage with, and too me, that's very cool.
If you place a few good ads in the article that are relevant, you can make a few bucks, but I only use advertizing that can benefit the readers, if the product is good, I tell my readers :)
hardlymoving from Memphis, TN on December 16, 2013:
You're right. If you spend time and effort writing a concise article with photos, the visits will grow over time. There are too many hubbers focused on making money by writing a lot of articles and/or getting a lot of followers. They eventually get frustrated and blame it on hubpages. All of my visits are coming from strangers doing Google searches. My initial article can be found on page 6 - 10 but eventually make to page 1 - 2 on a search. I believe the Google crawler primarily rewards writers based on: 1. number of words 2. number of original photos 3. grammatical correctness. 4. Specific key word(s). I also believe getting a Editor's choice helps as well.
I never started writing on hubpages with a profit incentive; actually, if anyone questioned my mechanically ability, I'd point them to one of my articles and suggest they do it themselves. Also, the idea of posting Ebay and Amazon ads came from one of the articles you wrote. Your content and ads flowed together.
Eddie Carrara (author) from New Hampshire on December 16, 2013:
I have noticed the same thing over the last 10 months, I'm thinking I'm going to hit over 1m views by January 1st, I'm crossing my fingers, lol. I spend a lot of time answering question for my readers, and the feedback from them is very humbling, I'm just glad I can help so many people with questions about their cars, and Hubpages has given me the connection to do so :)
hardlymoving from Memphis, TN on December 16, 2013:
Yup ... I'm still here. My articles have been picking up some real steam while I just sit back and observe. My record was 1,200 hits in a single day. The DIY on timing belt replacement gets the most hits ... about 250 + per day ... followed by strut replacement and ATF fluid flush (under 100 each). I've learned that there's no pay off based on the amount of effort placed on a specific article. It all depends on what the audience is interested in. Also there's been an increased stream in revenue coming from Amazon.
Eddie Carrara (author) from New Hampshire on December 15, 2013:
Hey Hardlymoving, what's going on? Good to see you're still active here :) Yeah, the nitrogen doesn't help much when you have a leak in the tires, but it does work a little better than regular air with the new tpms sensors, the cost is not so good, $100 for lifetime, I think air is much cheaper, lol. Take care.
hardlymoving from Memphis, TN on December 15, 2013:
Good article ... the nitrogen solution only works if your car doesn't have a rim leak ... which is why some of my customer's are surprised when I tell them they're low on tire pressure. "But I was told I'd never have to check my tire pressure!"