Why Does My Cars Low Tire Pressure Light Come On When it Gets Cold Out

Len, what are you doing up there?

I thought we could talk about TPMS sensors.

Talk about... You even wrote on the car? Geez. I leave him alone for two minutes.

What, it... It comes off.

All right. You're supposed to clean the car, not write on it.

I'm sorry.

What do you do... What do you want to know about TPMS?

There are so many things. Where would you start if I didn't know much about TPMS at all?

Well, this time of the season, I get a lot of questions of why all of a sudden is my light on? And it has to do with temperature change.

Temperature change.

...

We're live. Keep going there, dude.

Has to do with temperature change. Okay, so what are you trying to say? Because it's getting colder out right now the temperature inside the tires is going to change or...

Yeah. The cold contracts. So, say you tire is supposed to be set at 32 or 35. Every manufacturer has a different setting three to five pounds difference before the light goes on. So with the cold, you get up in the morning, it's 25 degrees, you get in your car and you start backing out of your driveway and you're driving off and all of a sudden the light comes on. And you're like, "Why me?" right? This happens and it always happens when you're running late. That's the key of it, right?

Yeah, that happens to all of us.

So what I like to do is like tell everyone to go on the door. Open your car door, most cars have a tag on the side and it gives you the actual tire pressure for the car. Never use the tire pressure on the tire.

So you don't go by the tire?

No because this is the manufacturer's recommendation for this tire not for the vehicle, the weight and the stability.

So it's just the maximum rating.

Correct, on that tire but not for this car.

That makes sense. Okay.

So you check the door, says 35 psi. So, in the winter, I'll bump that up to 36, 37. So that way the customer never sees that flex in that temperature drop and change.

That makes sense. Will the TPMS light turn on if only one tire was low, or do they all have to be low?

Depends on the vehicle. Some cars have the actual little tire things so that you can see which tire is lower than the rest. Some might just be a monitor that sets the light, so that means they all are on.

Oh, okay. Yeah, that makes sense. But I mean, does tread depth or anything have anything to do with the TPMS? Because, like I heard, some people say that if you have tires that are different sizes, then it can change, like, the rate of rotation on the tires thing. Is that true?

All depends if you have direct or indirect TPMS sensors,

Okay, so direct would probably be like the stem. That's part of the wheel or it's like it's attached to the wheel.

Yeah, It will be the bounce-down type or the sensor that wraps around the inside of the rim.

So, but what's the indirect then?

ABS.

Goes by the ABS.

So it goes by stability and the height. So if you put wrong sized tires on, you're going to get to TPMS light, because it goes by the rotation.

That makes sense. That totally makes sense. So what would be a care? I mean, if we know that the tire pressure is low, we add to it, and then tomorrow the light comes on again.

Well, you'd have to ask yourself, did you go by the spec on the door? So if you went by the exact spec on the door, or did you get a cheesy tip tire gauge too? You know, you get what you pay for, right? If you get that one that's on your key chain, I don't think that's accurate, bro.

Okay, yeah. Okay, I understand that. That's okay. So what if the TPMS light comes on and I'm not near someplace that I can actually physically check the tire pressure, like, I don't just carry around a tire pressure gauge in my pocket?

I bet you do. So what we would do is that...I mean, you know it's not safe to pull on the side of the highway and check your tire pressure, you know. You got to go with what you feel. If you feel the car wobbling or it starts to really pull to a side then, yeah, you probably have a flat tire.

Genius. Okay. So if it's just the TPMS light that comes on but you're not feeling anything too squarely, you're probably okay or would you still recommend just trying to get to someplace that I can check it ASAP?

I would say check it on your way. When you get to your destination check and see if the tire looks flat. If it doesn't look flat, I guarantee you, it goes out while you're on your way to work, because if it's only three to five pounds difference, it might go out once it heats up.

Okay. I guess that makes sense. You know, you're driving and the tire temperature warms up, the air inside expands a little bit.

And pressure builds up.

I mean, that makes sense. So what happens if I break one of these sensors like this, you said, is the direct, right? This is direct TPMS?

Correct.

So if this sensor breaks, is that something that I can just replace on my own? Or do you think that...

No, you have to bring the tire down, dude.

I can do that, a couple of pry bars, you know, with a hammer...bonk bonk.

Bonk bonk, yeah, you just did give it a little bonk bonk. You know, I think you might want to leave that up to the professionals because the stem is not cheap. I see them go anywhere from 80 to 180. So I don't want to break it, dude.

What? Unbelievable.

So I go to a shop, have them do it. That way they might have to also program it.

Program it too?

Yeah.

Okay. And you probably don't have to program with the indirect because that just goes by the ABS.

There's always a reset button usually for that.

Yeah, that makes sense.

So it resets itself. That's pretty cool.

It's kind of cool, I mean. So a valuable thing about having indirect over direct is that I wouldn't necessarily have to worry about the sensor breaking. I assume they have batteries in them too. I mean, the batteries last forever?

No. Yeah, right?

They're not like nuclear powered or anything like that?

No. They last about every seven years.

Huh. Okay. So seven years? I don't know what year this thing is, but we could have a probable cause here. What if I just walk around the car and I could tell that my tires don't look flat. I mean, I could go around and check all the tires because I'm a tire kicker and why not, you know.

Yeah you are.

Yeah. I mean these all look great.

So that's why you would check. You would check with a gauge like I personally have a digital gauge because they always just vary within a half a pound. The average is half a pound. You pay money for it, but I've had mine now for five years and they have little watch batteries. You change them, and it's accurate.

That's kinda cool.

Because you can test it too with the car. The car has a gauge in it, you know? Come on...

I know what you're talking about.

...digital one on and then you turn the car up and you're like, "Hey, my gauge is up." You can always reset it. They have a way to reset the gauges.

That's cool. That's really cool. I mean, I don't know. I'm just...

It depends on how serious you want to get about your TPMS.

Right? I mean, I don't want to go spend a couple hundred dollars on TPMS sensors just because a light came on. Like, if the light comes on and I check all my tire pressures and all the pressures are great, do I just rush out and buy all new sensors? Len's just throwing down the paycheck?

Well, yeah, I mean, you think about it, if you go in the car, say seven years and boop, light comes on, you're going to go to a professional shop that has a gauge. They hook it up and they go, "No reading, no reading, no reading, and reading." It's kind of like a headlight. They have the same age to them. You know, they burn time on a headlight. Same thing with the TPMS, that battery is the same age as the rest of the batteries. So yeah, you're going to have to buy all four. Don't buy five. Don't go for the fifth one.

There's no pool on the roof, huh?

No. For spare tires, some of the full size tire, I've had customers say to me, "Oh, I want that one changed," and I was like, "Whoa, someone's got money," because I don't really... If I have to put my spare tire on, I already know I have a problem. I'm just going to get to my destination. I'm not going to spend 200 bucks and waste it sitting in the trunk.

That just made me think of something when you said that the spare tire sometimes has a TPMS unit inside of it?

Correct.

So I check all four of these tires and I'm like my tires are perfect. My light's still on. I don't have one of those little scanner things. I mean, yeah, you can get them almost anywhere, but I don't have one to know exactly which one's wrong. Maybe I didn't check the spare. I don't even know how to check the spare.

Correct. So like SUVs, they have them mounted on the back, that has to be you always want to mount that stem, like at a 3:00 or 9:00. You don't want it straight down because it doesn't get activated. So you want the gyroscope to be able to... I don't even know if gyroscope is the right word, but that's how it activates. It keeps that battery going.

Yeah. Okay, so yeah because that means you keep moving around, so that it knows that it's activated. So this thing right here it's not just constantly talking to the brain of my car, is it? Is this just constantly talking?

Yes it is.

It is, huh?

Like you. Just like you, buddy.

Hello. Bonk bonk, yeah.

Guy's out of control.

Oh my Gosh. So let's break this down. Do you want to break it down?

The tire?

Yeah, I want to do it.

Yeah, why don't you leave and go get the spares?

I will get the pry bars and a hammer.

See you later.

I'm not really gonna do that... If we had a time machine though, that would be pretty neat because I would love to see the inside.

Can you write "Tire machine needed" right here?

Tire machine, please.

Budget. Put it in the budget.

I'm gonna put it in the budget and then see if I can get that. Yeah

What if they have to cut back on you? Oh, you're not willing to sacrifice now. Yes.

Smudges.

All right. I want to put a shout out to somebody named Karen. It's her birthday today. Happy birthday, Karen.

Happy birthday, Karen. I love birthdays. I love birthdays.

We got anything else we want to talk about?

Oh, man. There's so many questions that I have because... The TPMS light, like, how do you know that that is... How do you know which light is the TPMS light, basically is my question, because sometimes when I turn my key, the lights just all turn on. There are so many lights, and it's like nothing really jumps out and says, "TPMS." So...

I know. Do you want to drive? So it looks like an upside. It looks like a horseshoe, right?

Horseshoe.

With a little water underneath it, with a question mark.

Here we go.

All right. Now, he's gonna get all serious. That looks like a trombone.

It's okay. So maybe it is.

Yeah. That's pretty.

Okay?

Yep.

You know what, I feel like I remember seeing, like, that exclamation point. That one's the one?

That's, yeah, and it's usually in amber color. It's like an orange.

Amber. Look at me with the white. Unbelievable. So...

That is...

...it's amber.

That's the TPMS light. A lot of people, when they first came off...you remember that? Oh men. the people would come in, "I got a line on my dash," stopping on the side of the road. They thought the car was gonna do something awful.

They're calling you!

It's horrible. Yeah. And, back then, nobody had any aftermarket equipment. So it was always calling the dealer, calling the dealer.

Oh, really?

It was such a nightmare.

The TPMS is mandatory now, right?

That's true, federally.

Because they just stepped in there, like this is for safety's sake, because...

It's federally regulated for, like EPA for gas violation and all that kind of stuff, you know. Gotta save the zone, man.

I have to assume it's probably for safety as well because it's going to increase stability if your tire pressure is where it's supposed to be. If you're running low on a tire, stability is probably going to go down. You're going to have breaking issues potentially.

Handling more than anything.

Oh, yeah. Handling. Yeah, yeah, exactly.

We know he probably doesn't handle the car too good like this.

Oh, I race it.

Because you drive talking.

Depends on which car I'm in. Yeah, I have a car for everything.

Yeah, right.

I'm playing, just a Ferrari.

So I think we should...pretty much that's it. I mean, we might have missed some questions. You have any questions?

I feel like I wish I had a couple more questions for you because there's so many things that were running through my head. Man, that's why I drew these all up.

This is his life story right here, just so you know.

Unbelievable. Running late, light comes on. Well, yeah, I got a light coming on, that's for sure.

All right, dude. Good job.

All right. Good job.

Good.