Just a little question from me, what’s more accurate the onboard TPMS or my Michelin tyre pressure gauge. I ask because the onboard display shows the pressures to be about 2psi higher than what my gauge shows. Also how many PSI’s should the pressures increase by on a longish run on mixed roads? The display shows both fronts as 37psi when I started today, and by the end the left was 41 and the right 39/40.

Never had a car with TPMS so any insight much appreciated!

It says on the Fordpass app not to rely on the TPMS to be trusted as a true pressure gauge.
Always use a handheld unit for precise figures.
It's common for tyres to incresse 3 degrees or more whilst driving.

From the app-



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3 hours ago, Stoney871 said:

It says on the Fordpass app not to rely on the TPMS to be trusted as a true pressure gauge.
Always use a handheld unit for precise figures.
It's common for tyres to incresse 3 degrees or more whilst driving.

From the app-



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Interesting, it does say that it shouldn’t be used  as a substitute for the display in the dashboard which confuses things. I’m just a bit puzzled as the pressure gauge will say 36psi bu the onboard screen says 38psi.

I would be inclined to trust a handheld gauge to be more accurate than any tpms sensor.
Tpms is finexas a guide but hand held units are generally better calibrated.
I use one of these-

https://www.ebay.co.uk/itm/113028558087

It's handy as it has a fine bleed valve so you can release air without having to stab at the tyre valve with a key or screwdriver.

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