Tire Pressure Monitoring Sensors under report...

[rdfield]

at least in my case. I used two separate tire gauges to check my tires after refilling. All four times (reported by the two guageswere either 44 lb or 44.5 (when cold). The monitors report two tires are 41 lb and two at 42. Not a large difference, but something to note.

 

[AlanSubie4Life]

at least in my case. I used two separate tire gauges to check my tires after refilling. All four times (reported by the two guageswere either 44 lb or 44.5 (when cold). The monitors report two tires are 41 lb and two at 42. Not a large difference, but something to note.

Because you are at 3500 feet, your sensors will under report by about 1.7PSI. So your result seems about right.

The TPMS measure absolute pressure, not gauge pressure, and there is no correction for local barometric pressure; the car apparently assumes ambient pressure of 14.7PSI.

Fortunately you can now (I think - heard something about it but it is irrelevant for me) adjust the alarm threshold which is helpful for high elevation owners.

 

[rdfield]

Because you are at 3500 feet, your sensors will under report by about 1.7PSI. So your result seems about right.

The TPMS measure absolute pressure, not gauge pressure, and there is no correction for local barometric pressure; the car apparently assumes ambient pressure of 14.7PSI.

Fortunately you can now (I think - heard something about it but it is irrelevant for me) adjust the alarm threshold which is helpful for high elevation owners.

Thank you for the quick response; never thought about elevation (although I should have done so as I am aware that water boils in the high 190s here instead of 212).

 

[AlanSubie4Life]

Thank you for the quick response; never thought about elevation (although I should have done so as I am aware that water boils in the high 190s here instead of 212).

No problem. To be clear, you should be using your tire gauge to set the pressure to what you want, as normal. What the TPMS reads will be low and is incorrect, and will read even lower if you go up in the mountains further. If it starts bugging you about low pressures for this reason, you can use the new Service -> Reset TPMS Sensors to lower the warning threshold.

Of course, if you know the correct offset to use, you can also use TPMS to set the pressures correctly and forget about the gauge.