How accurate are the PSI readings from the TMPS?

[snowjay]

I have a digital gauge and it isn't really close to the TPMS readings. I have a dial gauge I can test with as well but I'm not sure how accurate that is either.

 

[rogersinsel]

I have a digital gauge and it isn't really close to the TPMS readings. I have a dial gauge I can test with as well but I'm not sure how accurate that is either.

I purchased a digital gauge from Walmart and it agrees with my TPMS readings. I don't know how often the TPMS polls for data, but mine appears accurate as long as everything is constant.

Define "isn't really close" please.

 

[snowjay]

I purchased a digital gauge from Walmart and it agrees with my TPMS readings. I don't know how often the TPMS polls for data, but mine appears accurate as long as everything is constant.

Define "isn't really close" please.

I checked the tires on Saturday morning, in the shade after sitting all night.

For instance, according to the TPMS a tire that was reading 34 showed 35.5 on the digital gauge. Trying to get the tire to 32 I let a little air out until I was at 33.5, the TPMS then showed 31. :/ I put a little more air in to bring the tire pressure up to 34 according to the digital gauge and then the TPMS read 33.

Not only wasn't it very accurate compared to the TPMS but it wasn't consistent either. So I wasn't sure who to trust. I eventually got all the tires to 33psi according to the TPMS and stopped paying attention to the gauge. The smallest amount of air out of the tires could affect the TPMS readings but not change the gauge reading.

I personally thing my gauge is hosed and will compare it's readings with my dial gauge to see how that does compared to the TPMS.

In my testing the TPMS polls pretty quick. I could add/remove air from the pass rear and by the time I walked around the truck to the drivers side the reading had already changed. Working on the drivers side I could actually see the pressures change as I made my change at the tire and walked to door to look at the dash.

 

[rogersinsel]

I checked the tires on Saturday morning, in the shade after sitting all night.

For instance, according to the TPMS a tire that was reading 34 showed 35.5 on the digital gauge. Trying to get the tire to 32 I let a little air out until I was at 33.5, the TPMS then showed 31. :/ I put a little more air in to bring the tire pressure up to 34 according to the digital gauge and then the TPMS read 33.

Not only wasn't it very accurate compared to the TPMS but it wasn't consistent either. So I wasn't sure who to trust. I eventually got all the tires to 33psi according to the TPMS and stopped paying attention to the gauge. The smallest amount of air out of the tires could affect the TPMS readings but not change the gauge reading.

I personally thing my gauge is hosed and will compare it's readings with my dial gauge to see how that does compared to the TPMS.

In my testing the TPMS polls pretty quick. I could add/remove air from the pass rear and by the time I walked around the truck to the drivers side the reading had already changed. Working on the drivers side I could actually see the pressures change as I made my change at the tire and walked to door to look at the dash.

When I air up my tires I usually go above my target and then let air out until I just reach the psi I want. You might try that. Because you never know if you are at 33.1 or 33.9.