[JSH]

Has anyone else seen where the tire pressure shown on the car's info screen is 3# less than that on a conventional pressure gauge?

[Alpha1BC]

Mine are usually within ±1 psi of what I measure with a decent oil-filled Longacre gauge, on rare occasions up to 2 psi off. How confident are you in the quality of your gauge? If it's a cheap stick gauge I'd trust the monitor, but if the gauge is decent and you trust that it's working correctly then I'd trust the gauge. 3 psi off isn't necessarily terrible but it would make me double-check my gauge since it's about a 10% difference.

[3Putt]

Yes, mine read low enough to get the warning at times and the dealer overfilled the original tires by 5 pounds. Anyway, I put on new wheels/tires/sensors and filled each tire to 35 lbs before installing. When I programed the sensors to the car, the psi readings have been more accurate.

Now all of that said, sometimes the car sits for a few days, when I check the psi via the app the psi is always changing. I'm guessing it's the temp of the garage and/or our altitude?

[JSH]

Originally Posted by 3Putt

When I programed the sensors

I took off the Goodyears and put on Michelins last week, which is when this problem began. Do I have to reset some data point here?

[h018871]

Perhaps the tire/wheels got switched side to side when the new tires were installed. If not reprogrammed, the right tires showing in the DIC will be on the left side of the car

[Vtor_ZL1]

Very close.. esp over time. AUtox.. when you adjust every run or two.. takes few minutes to average out the new reading.

[ctrlz]

My sensor monitoring results are always within 2 psi of my digital pressure gauge.
It is hard to know the exact correlation because the car reports whole numbers and the gauge reports in increments of 0.1 psi. I don't know if the car reports 34.6 as 34 or 35.

[grampa_ss]

Originally Posted by JSH

Has anyone else seen where the tire pressure shown on the car's info screen is 3# less than that on a conventional pressure gauge?

Mine is always 2psi lower.

[foshjowler]

Mine seem to be very close, at least within 1 PSI. Close enough for daily driving. I don't have sensors in the autox wheels since I'd be checking those with a gauge anyway.

[Plasar]

• I'm a big fan of car tire pressure readings to help you keep in tune with your tire pressures - this way you get a reading every time you drive instead of whenver you get around to measuring with the manual gauge. (I like electronic oil level measures too, rather than dipsticks.)
• Having said that, these systems drive me nuts because it is so hard to get 4 equal pressures on 4 wheels.
• My 2008 BMW M3 read to the nearest 0.5 PSI. It was fine, but seeing tires 0.5 off was slightly annoying.
• My 2012 AMG C63 read to the nearest 1.0 PSI, and it took a little time to get things balanced, but seemeed to be spot on.
• My 2017 Camaro is fine, but the issue seems to be that the tires might read equal at cold temps with all 4 wheels, but then when warm, they are off by 1-2-3 PSI. If they are equal warm, then the left side seems down 1-2-3 PSI, not always equally.
• I would love to see the pressures equal at cold and equal at warm.
• Good news though - Costco Senter Road San Jose just installed 2 automated air pumps - you dial in the pressue, and it fills to that pressure automatically. I'm stoked for this.

[arpad_m]

The differences on mine are within ±0.5 psi between the TPMS sensors and the manual gauge, maybe I just got lucky with the sensors.

I will say that the tires build temperature following different paths, even if their cold pressures are equal, a 1-2 psi difference is displayed while getting heat into them during the first couple of miles, but when warmed up, pressures are very close (displaying equal) again. Makes sense if I consider that tires are unlikely to be experiencing the same exact amount of load while driving on the street.