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Tire pressure monitoring system

I recently purchased a new car that came equipped with a TPMS, tire pressure monitoring system. The car came with green valve stem caps. I’ve noticed other cars that are equipped with TPMS that also have green valve stem caps. I’ve always wondered why. I decided to buy some chrome valve caps. As I was waiting to pay for them, I happened to read the back of the package and it said not recommended for cars with TPMS because cap could become bonde to valve stem. Why is that?

They are not recommended because they don’t have the hardware in them to tell the car’s computer when to turn on/off the warning light. Stick with the original caps.

BTW all this should be in your owner’s manual. Tomorrow would be a good time to give it a good read cover to cover.

So there’s actually hardware in the green caps, it just looks like a regular valve cap only green?

There is nothing in the caps…They are there to alert tire busters that the car is equipped with TPMS and they need to take precautions when servicing the wheels/tires.

Sometimes the green caps denote the tires have been inflated with dry nitrogen instead of compressed air…

Just two more ways to get into your wallet…

I believe the warning. There was a recall for my Acura MDX to replace the original metal caps with plastic caps for exactly this reason.

I always thought that green caps meant the tire was full of nitrogen, but I could easily be wrong about that.

I think you’ll find that the green valve caps means the tires were filled with nitrogen.

I also think you’ll find that there are reports of valve stem breakage - hence the reason not to use anything but the valve caps supplied.

You don’t have to have green caps - just non-metallic ones. If you want to get a set of black caps, you’d be fine.

The green liquid “fix-a-flat” that is put in tires sometimes includes green caps.