Altitude and tires

I have a 2009 Rav4,bought used with now 37,000 miles. I live at 7500 ft. and the check tires light came on. I had them checked and pressure checked. After the light went off I drove to about 10,000 ft. and the light came on again. I brought it back and the guy said that the altitude and cold weather causes this. The light is still on. Whbat to do?

Keep your tires properly inflated.

There should be a procedure in the Owner’s Manual for resetting the TPMS light. Follow it and save yourself a trip to the dealer/mechanic.

Thanks. Does the different pressure at higher elevations require a variation in the manual’s recommendation?

First, some basic physics:
When temperatures drop, so does the pressure in your tires, to the tune of 1 psi for every 10 degree drop in temperature. Higher altitudes almost always mean exposing the car to lower temperatures, so a drop in tire pressure would not be surprising.

Secondly, there is a tire pressure sensor located in your spare tire, as well as on the four tires that you drive on. Has anyone checked the pressure in the spare?

A friend of mine has a 2008 Rav-4, which is essentially identical to yours. When his TPMS light went on a few weeks back, he was stymied because he checked his tires and found that they were still a couple of lbs above the recommended minimum pressure.

I took the cover off of his spare and found that the spare was down to 18 lbs. A few minutes with my air compressor and some careful rechecking with a tire pressure gauge brought the spare back up to 36 lbs, where I wanted it to be (a little extra pressure will prevent having to go through this scenario again for awhile).

And, finally–if you don’t have your own tire pressure gauge, you need to get one, for obvious reasons.
Don’t waste your money on a cheap one. Buy the best quality dial-type or digital pressure gauge that you can find and it will serve you well for many years.

The dial-type gauges with the “Slime” brand are low-quality, and can be counted on to fail within a year or two. By contrast, my dial-type gauge, purchased from Brookstone about 20 years ago, is still going strong.

I don’t know what Toyota used in the '09 Rav4 for its TPMS setup, but in my '05 Scion tC they used the wheel speed sensors. The computer monitors the speed variations and trips the light when one or more varies from the “set” speeds.

My Owners’ Manual defines two different protocols in different sections of the manual, one for “resetting” the TPMS system and the other for “reinitializing” the TPMS system. The first protocol resets the light, leaving the system referenced to the established baslines. The second protocol reestablishes the baselines. The manual clearly states thet the system must be “reinitialized” whenever new tires are purchased, which suggests that the system is very sensitive to variations.

I’d suggest reading the owners’ manual carefully. You may have the same type TPMS system that I have, and you may need to “reinitialize” it.

Add pressure to your tires.
Nowhere in your post did you actually state that you took a tire pressure gauge to any of your tires while the light was on.

I live in Denver, and have 2 different vehicles that have TPMS systems on them.
I regularly drive from 5k feet to 12k feet, and not once has the TPMS light gone on when the tire pressure was correctly set in Denver.

It has, however, gone on when it was low, or when the temperature dropped a large amount (think from the 70’s to the 30’s). Every 10 degrees colder air temp, your tires will show that they are 1 psi lower.

So, go get a tire pressure gauge, and check your tire pressures.


Thanks to all for your good advice. No, I haven’t checked the spare although I frequently check the others. I think I’ll get a high-quality gauge too.


Since the '08 Rav uses sensors in each wheel, I believe that the essentially identical '09 model has the same type of equipment.

I believe that when the OP checks his spare, he/she will find that it is the source of the problem.

If you want an accurate gauge, odds are that you’ll do better with a dial type or a digital type. The pencil type tends to be less accurate. I’m partial to dial gauges from Accu-Gage, as I have several of them and the readings match exactly.

Make sure you’re checking the pressure when the tires are cold.

As long as you have a gauge in the car, don’t forget that you can inflate the spare to the maximum allowed for the tire and then let out air as needed if you ever have to put the spare on.