Did your know that the tire monitoring on Fords is NOT that accurate?

[GWink]

One of the senior service techs recently told me that the TMS on the Mustang is only accurate to within + or - 3 PSI……….that means if your dash is telling you the correct 31 PSI, your tires could be at only 28 PSI or as high as 34!! Driving at highway speeds could get that upper figure to 38+…..I recommend a really nice pressure gauge (not the plastic ones) to cross check the OEM TMS…..

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[erocker]

My car seems to match up pretty well with all the gauges at my shop. Similar to most cars.

 

[krisk]

One of the senior service techs recently told me that the TMS on the Mustang is only accurate to within + or - 3 PSI……….that means if your dash is telling you the correct 31 PSI, your tires could be at only 28 PSI or as high as 34!! Driving at highway speeds could get that upper figure to 38+…..I recommend a really nice pressure gauge (not the plastic ones) to cross check the OEM TMS…..

I check my tires after every run on the track and have never had the tpms more than 1psi different than my gauge. The tolerance may be 3psi, but I’ve never seen that much difference.

 

[GrabThatBlue]

That's the tolerance.

 

[dusman59]

I find the tpms right on with all my gauges that I use. Haven't heard of any complaints on the forumn until now.

 

[steveo1960]

Seem to match my Jaco and other generic gauge within 1 PSI. I do have a slow leaker in one tire that loses like 2 lbs over a month or so. I'm leaving it alone for now. Don't want plug, rebalance etc. I don't see anything obvious.

 

[Frogdog1]

The TPMS Ford has are garbage. I set my pressure with a Longacre Racing gauge I used when I raced bikes where the pressure absolutely cannot be off. I don't even pay attention to the TPMS in the car.

 

[LouG]

I use my own accurate tyre gauge, it seems to match every time.

 

[Neggytive]

Schrader makes the TPMS sensors and IMHO they are some of the best out there.

Cripes just PSI from 48 to 75 degrees is 3 PSI different

Here's the deal, we are FORCED to have TPMS sensors by the Feds because of the BS Ford and Firestone did in the mid 1990's with the Explorer

Because they recommended those tires be run at under 30 PSI for ride comfort, because the Explorer was way heavier than the suspension was designed to handle ( Mazda B2000 was the original design they built it in) and nobody ever checks their tires anymore , when the tires were run under inflated they failed, the vehicles would roll over and bad things would result.

I remember seeing them in tow and salvage yards it was not pretty

The TPMS is going to be pretty close to actual, but more importantly it's main function is to warn you when a tire goes more than a couple of PSI lower than the value stored in the computer for nominal. Notice you don't get a warning when they are over inflated, just under.

And most of the lube rack monkeys at any dealership are not setting the pressure when the tires are cold, especially in the fast lane oil change operations. Any pressure where the tire has heat in them is going to be wrong.

 

[RLE55]

I use a good tire gauge when checking psi's. The TMS is only used to let me know if there's an issue, i.e. psi way low or high.

 

[dusman59]

My Ford Pass notified me that I had my right rear tire low sitting in the garage. Sure enough an ugly screw with only 400 miles on the tire. I would think other car manufactures use the same type sensors Ford use. I guess they all use garbage but seem to work just fine.

 

[AZ_Ryan]

One of the senior service techs recently told me that the TMS on the Mustang is only accurate to within + or - 3 PSI……….that means if your dash is telling you the correct 31 PSI, your tires could be at only 28 PSI or as high as 34!! Driving at highway speeds could get that upper figure to 38+…..I recommend a really nice pressure gauge (not the plastic ones) to cross check the OEM TMS…..

Well yeah, never take the TPS on any car as gospel. But plus or minus 3 psi ? Thats rediculous. That may be the "accepted tolerance" but its certainly not normal. To me, if they are that far off they aren't working right.

I've always found my Mustangs TPS to be within .5 - 1 psi of my guages.

Also a fun fact - those TPS batteries don't last indefinitely.

 

[Wiley Marmot]

My TPMS always reads 3 PSI less than my Victor dial gage and my 12V air pump gage (which are synced with each other). My driver side front TPMS frequently reads 1 PSI higher than the passenger side front TPMS; even though the Accugage and air pump are saying both fronts are at the same PSI. WTHeck?!

On top of all that; I'm running a staggered 19" LMR wheel/tire set which is specced 4 PSI lower (32PSI vs 36 PSI) than the OEM 20" all seasons; putting me close to the 28 PSI low pressure threshold of the TPMS. And................I'm not running the recommended 32 PSI spec on my LMR tires; instead running 30 PSI rear and 34 PSI front to get even wear patterns across the entire tread widths.
My dash low pressure LED has been on for months now.

 

[AZ_Ryan]

My TPMS always reads 3 PSI less than my Victor dial gage and my 12V air pump gage (which are synced with each other). My driver side front TPMS frequently reads 1 PSI higher than the passenger side front TPMS; even though the Accugage and air pump are saying both fronts are at the same PSI. WTHeck?!

On top of all that; I'm running a staggered 19" LMR wheel/tire set which is specced 4 PSI lower (32PSI vs 36 PSI) than the OEM 20" all seasons; putting me close to the 28 PSI low pressure threshold of the TPMS. And................I'm not running the recommended 32 PSI spec on my LMR tires; instead running 30 PSI rear and 34 PSI front to get even wear patterns across the entire tread widths.
My dash low pressure LED has been on for months now.

Have you verified its not the guage you're using?

 

[dusman59]

@Wiley Marmot did you reuse the sensors from your original wheels? Were you noticing these readings with the OEM setup?

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