It's been in the high 90's all this week. My car sits out in the parking lot at work all day. When I hop on the freeway my (!) comes on after 20 miles or so. The first time it happened I pulled over & checked my tire pressure. They are all at 35psi. The next morning (cool car) it stopped flashing. The next afternoon on my way home it happened again around the same distance. Also when the (!) is flashing my keyless remote stops working too. Anyone else have this happen?

 

heat shouldn't have anything to do with it really

 

Mine does the saem thing. It does happen after the tires warm up but the outside temp doesn't affect it cause mine did it in the winter too.

 

But there is no upper limit that sets off the warning light. The light comes on when the pressure drops below 26 psi (or 29 psi i forget) and then turns off when the pressure rises above 32 psi.

In the winter time i could see the pressure dropping to 29psi setting off the light and then going away after a long highway drive raises temp and pressure to 32. But in the summer, the temp would rise. If he said his pressure was 35, then it could have been 32-33 at cold rest. Still shouldnt set the light off.

Usually when the light comes on after some period of highway driving, it could be a sign that a sensor is crapping the bed and failing to register. I see heat more as a coincidence.

 

If you recently had tires install without re-programming the TPMS, the (!) light will go off after about 20 miles of so.

 

I've had my tires for over a year, there were reprogrammed then. I'm thinking I might have an electrical problem because my remote stops working when the (!) is flashing.

 

Mine acts up as well. I drive for long highway trips and it usually goes off about 2 hours in. TPMS more or less senses a pressure differential between all the tires and will go off when it senses more than a 7% difference.

I usually crack it up to the tires heating as I'm rolling down the road for long periods of time, but it's probably not the case. They all end up even when I check too.

Wouldn't worry about it, but do check the pressure fairly often because my TPMS went off and I did have a pretty low tire at one point.