Erroneous Tyre Pressure Indication
 

I'm getting an erroneous tyre pressure warning every once and a while. All tyres are safely at 43 PSI and I can clear the warning once I've stopped the car. I'm assuming it's a faulty sensor but is there a quick and easy way of figuring out which one?

I'm having the same issue after changing my CV boot and brakes. TwinsPappa just put on his snow tires and experienced what we had and he let me know what he did in my thread "Got my V8!"
I'm going to try his system today and see if it works.

Good luck!

Side issue, but why would you have your tires at 43 psi? Doesn't seem at all safe to me.

Thanks Big J will check it out.

The tires weren't cold when I got the warning. I got the warning after a couple of hours driving. When I say safe I believe 43Psi for a hot tire is a pretty safe......... no?

You're definitely at the upper end of the "safe" limit. The ride must be terrible.

Hot tires will typically read two to four psi higher than cold. I have 18" wheels on my 2006 X5 4.4i and run 35 psi cold. Also, when checking, make sure that your tire pressure gauge is accurate!!!

I've got 20's on mine so I run them a little higher around 38 cold

Should be closer to 32 psi, all tire sizes, unless you are carrying four people and a full load of luggage. Then the owner's manual says to take the rears up to 39, but to keep the fronts at 32. 20" tires do not require higher pressures. That is from my 2003 model owner's manual, not sure what year you have but it should be similar.

Too high a pressure is definitely not safe. And if you have moisture in the air from the compressor, you will get more variation than if the air is dry, as it is the moisture that expands more so than the air as the tire heats up. The sensors are seeing a variation between tires, not just a low pressure, so too high a pressure in one tire could cause the sensor to go off as well.

Suggest you set all tires to 32 psi cold (or 35 if you insist) and then see if you continue to get nuisance warning lights.

Good call, will try it, I've always run my tyres a little firmer than recommended but will take your advice onboard :). Will be interesting to see if that gets rid of the alert

Thanks
Andrew

Hey Andrew,
The page belwo is from my 2006 Owner Manual. Make sure your tires are cold before adjusting them. As JCL mentioned moisture content in the tire plays a big role in expansion. Some of those underground pumps that you find in your local gas stations have very high moisture content. If you use them I suggest letting the air out for a while before you actually fill up your tire. In some cases, you can actually see water drips from the air hose. And that’s why I bought a small air pump long time ago. I usually check the tire pressure once a month when the car has been parked over night.

Good luck,


Ashkan

https://lh5.googleusercontent.com/-x...2BPressure.JPG