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Dashboard lights for flat tire

Help! Three times this week I have seen the dashboard indiocator light for a “low pressure/flat” in the tire appear. Twice got air in all tires, then rotated and dealer says nothing wrong: just the cold. It is like 45 degrees-not the South Pole here. Drob=ve the (RAV 4) all last winter and never had this happen. Dealer says they tested and no leaks. Today, same problem. Am waiitng to go outside at lunch time and fear for the flat tire, before I once again, drive it to the dealer.

Low air pressure sensors are not a particularly precise technology. They are also not particularly necessary. We got along for 100 years without them.

So long as someone has examined the tires and sees no evidence of a flaw that would fool the sensor, I would ignore it. If the sensor still gives false readings with your next set of tires, I would remove the bulb.

Why is ignoring acceptable? If it is in warranty, then make them fix it.

What is the recommended pressure? What is the actual pressure when the light comes on? We can’t help you if you don’t supply obvious information like this.

Check and maintain your tires the same way you ALWAYS should. Rely on the dummy light only as supplimental, such as while actually driving and something happens while in motion.
Buy yourself a little 3.99 tire guage, learn you car’s psi specs, learn how and when to adjust your psi, Learn what to look for as you see each tire’s condition.
When you know the tires are right you can always continue driving with peace of mind.

Toyota uses a direct tire pressure monitoring system, meaning there are sensors mounted inside the tires. Perhaps one of the batteries in the sensors is bad, and sending a poor signal. How old is the vehicle?

I was operating on the assumption that it was out of warranty, else the OP would have stayed after the dealer to fix it rather than asking our opinions.

Have someone check the spare tire.

I’m on my second vehicle equipped with these type of systems. Since I live in the northern climate, anytime we transition from summer to fall, the cooler air will cause the air pressure to drop in the tires. It can trigger a warning light depending on how sensitive the sensors are.

Now, another potential issue is those silly people at the quicky-lubes. They offer a full service including checking your tires pressure. But for $6 - $8/hour, these guys are not rocket scientists. They can set your tire pressure where it is supposed to be. Only problem, is that pressure is for when the tires are cold. You drove to the quicky-lube so typically your tires are hot and at a higher pressure because of the heat. So once the tires cool back down at home, the sensors can trigger the next time you go to start the car. I have personally had this happen. I take good care of my tires and get upset when amateurs mess with my tire pressure.

So, it could be that you have a slow leak in one tire causing the sensor to trigger. Or it could be the temp difference and how close you were to the sensor trip point. Or the sensor could have a trigger point that is close to the cold tire pressure. These are cheap sensors.

If it is under warranty, make the dealer fix it. If not, buy a tire pressure gauge yourself and check the pressure first thing in the morning so you know what the pressure reads when it’s cold.

I second the motion.