TPMS PSI isn't accurate

[atari]

So I've been running around for a year with my tires at 30 (proper for my Ranger) according to my dash TPMS numbers.

I recently got a compressor (which measures tire pressure) and a good dial analogue gauge. The compressor and the guage match each other perfectly. But when my truck shows 30psi they show 25.

So I filled them all up to 30 with my gauge, ride feels great, but why is my TPMS off by so much?

I found instruction son how to re-train the wheel locations, but not sure if that will help the PSI readings?

Are everyone else's TPMS numbers accurate?

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[D Fresh]

That's odd. Mine read just about spot on.

 

[rydfree]

So I've been running around for a year with my tires at 30 (proper for my Ranger) according to my dash TPMS numbers.

I recently got a compressor (which measures tire pressure) and a good dial analogue gauge. The compressor and the guage match each other perfectly. But when my truck shows 30psi they show 25.

So I filled them all up to 30 with my gauge, ride feels great, but why is my TPMS off by so much?

I found instruction son how to re-train the wheel locations, but not sure if that will help the PSI readings?

Are everyone else's TPMS numbers accurate?

The manual states that the TPMS readings should not be used in place of actually checking the tire pressure . Mine are spot on though . The wifes car has a checkbox in the TPMS menu that allows you to calibrate the onscreen psi to actual tire pressure so surely the Ranger allows that to be performed also .

 

[Msfitoy]

Mine's pretty accurate...are you reading right after changing pressure while static? TPMS won't read changes until after few miles of driving...

 

[Bob902]

Mine are on the money

 

[Delirious]

That's odd. Mine read just about spot on.

So are mine.

 

[CATX]

Mine read about 4 -5 PSI too low at each wheel. I returned a new gauge because it disagreed. But after that, 2 other gauges that I tried and the filling station gauge told me the same thing.

Also at delivery the pressures read 49 PSI - probably more like 54 (recommended is 39).

 

[Langwilliams]

I've checked my tire pressure with with digital an stick style pressure gauge an it matches the reading.

 

[LoneRNGR]

But when my truck shows 30psi they show 25.

Mine have been very accurate until recently. Now the dashboard shows the air pressure to be about 2-3 psi more than they actually are.
Edit: all four are reading the same difference, which leads me to believe it is a software problem.

 

[Cactus Jim]

Same boat here. All four tires read 41psi after dropping all 4 down to 34psi. After driving 10 miles they still read 41.

 

[outdoorphotog]

Ford app shows about 4psi higher then actual air pressure

 

[JohnnyO]

Mine are on the money

Same.

 

[atari]

Crazy how there's so much variance.

After filling to cold 30 on all tires, driving around for 20+ min, my TPMS now show: 33,33,33,32
So it looks like they're all working the same (there's probably less air in the 32 tire legitimately), but all are 3 over what it should be.

 

[puckdodger]

Mine are off by a couple PSI too, I think, I can't say for sure because have no idea which is correct, the TPMS, my own gauge, or the one at the gas station?

Reminds me of a saying my grandfather had: "a man with two wristwatches never really knows what time it is..."

 

[Rp930]

After reloading the app twice mine are dead on.

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