My tpms is reading 34 but my tire gauge reads 30. I have another gauge that reads 32. Trying to figure out which is correct.

Does the tpms only take readings periodically like the outside temp, or is it constant? Is it known to be accurate?

 

It's more accurate on my Jeep than any of my gauges, and I have several. The gauges are all over the map. The TPMS is consistent wheel to wheel. I have one gauge that matches the TPMS number pretty much right on the money so I can confirm that each tire matches. I'd say TPMS is far more accurate than an uncalibrated gauge.

 

The TPMS on my '13 are about spot on to the digital gauge I use, and they are consistent from tire to tire on mine.

 

I have several gauges. Digital, pencil, and dial. They all read just slightly differently from each other. And my TPMS sensors on all five of my wheels read about 1 PSI higher than what I feel is my most accurate gauge. So I'd say they're all pretty accurate. They DO update on the fly, but I do not know the time interval between updates. I know I can start driving on cold tires and watch each reading increase steadily over a short drive, so I'm guessing every minute or so is the outside of the update time.