hi guys

can somebody explain this? long journey today (250 miles +) some in snow some not however at about 200 miles in (on the a68 just into scotland) the tpms warning comes on saying pressure loss and at the same time the bonnet open waning comes on. Stop at next layby bonnet is fine but open and close it and warning goes off, tyres look ok but stop at next garage to check and yes all ok. reset tpms and continue - no probs. any ideas

The tyre sensor is not a tyre pressure sensor, it works in conjunction with your abs sensing the revolutions of each wheel, normally when one tyre is starting to deflate the circumference will be less than normal so will be more revolutions on that wheel so off pings the sensor, you said you have travelled in snow maybe one wheel spun, and did you check with a digital monier or just visually, sometimes just 4 psi can sett them off at higher speeds as more revolutions 

Hi blue

It didn't happen on slippery stuff it was clear road been in cruise at about 60 for ages . Checked tyres at shell station and they were all identical - beats me !

I found when I have the tyres on higher pressures, such as 38, I get the TPMS warning on freeways occasionally, sitting on cruise at ~100km/hr.  I lowered the pressures to 34-35, for inner city driving and found the TPMS to be more stable.  I just keep a digital gauge in the car now and double check the tyres if the TPMS does go off.

Interesting Christian - yes mine are set at 38 and most of my cruising is at that sort of speed will keep an eye out and see how it goes

John

It's a feature. I've got the same alert few times (during one year) mainly in winter conditions. My thinking is a) caused by slippery surface and/or caused by harsh environmental conditions triggering temporary sensor glitches. Have you calibrated the tyre monitoring system ? If the calibration is bit off-the-scale to start with, I guess you could get the alert more frequently.