TPMS accuracy 2022 Mustang GT Premium

[wynand32]

Just bought a 2022 Mustang GT Premium California Special, and I'm in that initial paranoid stage of worrying every little detail. Right now, I want to make sure I'm maintaining the car appropriately, including keeping up with tire pressure.

I've noticed that the TPMS readings in the FordPass apps are all over the place. They don't correlate at all to the readings I get with my cheap pressure gauge, and they don't make a lot of sense. Are these reading expected to be accurate, or are they essentially just approximations?

Sponsored

 

[gadgtfreek]

My 2019 and 2021 GT TPMS systems have been very accurate.

 

[Vlad Soare]

Mine too. Very accurate. I have two high quality digital gauges, and all four of the TPMS sensors agree with them to the nearest tenth of a bar.

 

[Offshoregames]

The ford pass app will only show what the pressure was last time it communicated with the car. The pressures displayed in the dash readings I find to be very accurate for me.

 

[Skye]

They don't correlate at all to the readings I get with my cheap pressure gauge,

Before Skye, I'd used a like gauge for many years.

With the new car and readings I was getting, I began to question the old gauge.

I splurged, buying an Autometer 2160. The result? TPMS and Autometer mirrored one another.

The 2160 is a great gauge; there are several other like gauges in the same class.

Treat yourself and the car to something nice.

If tires are checked, I do so in the AM, before driving. Once driving, TPMS then mirrors the Autometer readings within the first 100 yards of movement. I have seen Ford references that, once in motion, it can take up to two minutes for all TPMS sensors to wake up and report readings to the car.

The Ford Pass app does not necessarily report real time info. The app will often display a time as to when those readings were last drawn from the car. Even swiping to update the app, I often see results that say, "information ## minutes old.", or something to that effect.

In my readings, I have confirmed TPMS, the car and the pass app round up/dn, by 1/2 psi. For example, setting the tires at 33.5 with the gauge will display 34 in the car. The car and apps only report in whole psi increments.

 

[Johnnybee]

Mine are pretty much spot on. I set at 32 and three read at 32 while one reads 31 but after less than a mile the odd one will read 32. As noted above, they only read in whole numbers so that explains my odd one.

 

[wynand32]

Huh. Thanks for the responses. I'm getting a (hopefully) more accurate gauge from Amazon today, I'll check again.

What's weird is that with one reading it'll show a tire as being lower than the others and then with another reading it'll show that tire being higher. I understand the lag in the FordPass app, but that shouldn't account for the wonkiness.

Like I said, though, I'll check again with the better gauge. Nothing like the one referenced above, maybe I'll check that one out if this one ends up being inaccurate.

 

[Wingnutzz]

When the car is parked, I can see the difference in tire pressures from the ones that are in the sun vs shade. For street driving I’m fine as long as the cold pressure are close to that prescribed.

 

[wynand32]

When the car is parked, I can see the difference in tire pressures from the ones that are in the sun vs shade. For street driving I’m fine as long as the cold pressure are close to that prescribed.

Well, now, that makes way too much sense. The pressure could certainly change a pound or two in response to being in the sun or shade, and my care is pointing north/south. In Southern California.

 

[Cory S]

Well, now, that makes way too much sense. The pressure could certainly change a pound or two in response to being in the sun or shade, and my care is pointing north/south. In Southern California.

A 10-12°F of internal tire air temperature increase/decrease is around 1psi.

15-20 minutes of driving (normal) at 65° ambient, will usually raise pressure by 2-3psi.

 

[wynand32]

A 10-12°F of internal tire air temperature increase/decrease is around 1psi.

15-20 minutes of driving (normal) at 65° ambient, will usually raise pressure by 2-3psi.

Excellent, thanks!

 

[gadgtfreek]

Exactly. Right now we've dropped from 80's in the morning to 60's. So my tires are around 33 cold. When I get to work after a 25 min drive, they are 35 ish. I need to add a few pounds to each one for the new colder temps.

I use the app at least once a day to do a quick check of tire pressures.

 

[wynand32]

So, last night at about 9:30pm, I used my new digital gauge to set my tires at 32 psi. Looked at the FordPass app and it was listing 32 for all the tires (actually, 31 for one, but I didn't hit 32 exactly in all of them so it was theoritically a rounding error). So I thought I was good to go.

I got up this morning, refreshed my FordPass app at about 8:30am, and it said my tires were at 30 on three and 31 on the fourth. I'd thought that maybe they weren't actually "cold" last night because it was still about 75 deg F when I adjusted things.

When I checked with my gauge, though, the two facing the morning sun were at about 32.5 while the two still in shade were at 31.5 or so. I checked with another digital gauge and they showed about .3 pounds less across the board, so just a slight difference between those two gauges.

I put some air in the two that were under 32, and now the FordPass is showing 32 on all but the left front (sun-facing), which shows 31. My gauge shows about 32.5 on each tire, give or take a tenth of a pound or two.

Long story short, I don't know exactly how to interpret these results and how much to worry about it. I know it's worse to be underinflated than overinflated in general, and I'm not sure how much a psi or two makes a difference. Clearly either the TPMS is slightly off, or my gauges are both off.

I'm in that initial paranoid stage about the car. Any input is appreciated.

 

[Cory S]

Long story short, I don't know exactly how to interpret these results and how much to worry about it. I know it's worse to be underinflated than overinflated in general, and I'm not sure how much a psi or two makes a difference. Clearly either the TPMS is slightly off, or my gauges are both off.

As long as your between 32 - 42psi, you're good to go. The differences will be ride harshness at higher PSI, but ever so slightly better MPG.

 

[Linkster1666]

I like to check tires about every time I drive, optioned in the 401a, screen has tire pressures. Set them at 32, by the time they warm up they are at 35 and pretty much stay there depending on travel type, sun shining on left rear more, or what ever.

Not a daily driver so, I'm not going to panic over an ALLEGED psi.

Sponsored