This morning after the wife's car sat out in the 17°F night air she got a Tire pressure light on the dash.

 

She added only 2 PSI in two tires and one PSI in another light went out!

 

How sensitive are they, what range are they "programmed" to say is OK.

 

Is there any way to adjust said range?

 

This is second time this has happened, getting a little annoyed.

 

Especially because next year this time it will be mine, after getting her one with fewer miles.

 

 

 

Thanks for any input

 

 

Greg

 

dunno the thresholds/hysterisis

 

you're fighting physics when the temp drops a lot; https://en.wikipedia.org/wiki/Ideal_gas_law

Edited January 13, 201610 yr by 1 Lucky Texan

If you're that worried about it, when they're cold, set them like 2-3 psi above the sticker on the door. Then when the temp drops the psi will still be above the threshold. 

 

I'm not quite sure the exact psi, but if the spec is 30, it most likely will get set at like 26 psi. So yes, it is sensitive, and once you start driving the tire warms up and therefore it will raise 2 psi and may jump above the low level and the light goes off.

Depends in the car, but usually a difference of 2 psi is enough to set them off.

 

I used to tell people at the service center to just drive it, once the tired warm up it will go off.

 

If you are worried about having a light on during the winter months have you tires filled with nitrogen/air mix. Most tire places do this for a couple bucks extra and will keep your tire pressure from changing when it gets cold.

I've been happy using a 78% Nitrogen mix.

Took a few minutes on this slow day at work to dig into the FSM

 

Monitor indicator turns at 26.11 PSI turns back off at 29.01PSI

 

So the system allows for a 4 lb drop, before alarming.

 

 

Did find out that the reading is sent to the brain box every 30 seconds or so.

 

And also the battery is good for 10 years, but is not replaceable .

 

You are just to replace the entire sensor.................

very brief glance at a few websites yields a rule of thumb close to - a drop in temp of 45-50*F ill cause a drop in tire pressure of about 4psi.

 

So, if you were in the middle of the 'range' - temps only need to drop 25*F or so to trigger the light.

 

 

 http://www.tirerack.com/winter/tech/techpage.jsp?techid=73

 

 

Edited January 13, 201610 yr by 1 Lucky Texan

And also the battery is good for 10 years, but is not replaceable .

 

You are just to replace the entire sensor.................

Yes and they make it a PITA to change tires since the sensor is easy to break off when dismounting the bead.

 

I hate TPMS systems.

I've been happy using a 78% Nitrogen mix.

 

Ha, ha, I got that joke...