Tire Pressure Monitor icon keeps going off

[soupcxan]

I bought a new 2011 HL V6 SE in June this year. Now have 1800 miles on it. A month ago, on the first "cool" day (e.g. 70 instead of 100, this is Texas) my TPMS icon appeared when I started the car in the morning. I checked all the tires and they were a couple of psi under 30, so I inflated them all to 35 psi. Monitor icon went away. The door sticker for my tire says 30 psi is the recommended pressure.

A month later (today) was another relatively cool day (70 instead of 90). When I started the car in the morning, the TPMS icon was back on. I checked the tires and they were all between 33 and 35 psi. Drove ~10 miles and the TPMS icon is still on.

Does anyone know why this is happening? Thanks for any info.

[summerwind]

Probably the spare. Unless something is different from 2008 all five tires are monitored
Lower it and check the pressure (it is also a good time to find out how to do it if you are caught with a flat).

If it is to spec that a dealer trip you should go.

Also here is a thread on how to find the TPMS reset button on an 2008 HL.
Assume it is in the same location for 2011

http://mojavetrail.webng.com/TPMSreset.pdf

[thenebula873]

Yup...drop the spare and reinflate it. Happened to me once...inflated all 4 tires to 35-37 psi but still had a warning till I dropped the spare and put 37 in it.

[DavidHB]

if it is the spare why did the monitor light go out the first time?

[TrailDust]

Originally Posted by DavidHB

if it is the spare why did the monitor light go out the first time?

Could be the spare is right at the TPMS threshold, so when the temperature increased later that day the light went out as tire pressure increased as well due to the temperature rise. Rule of thumb is tire pressure changes about 1 PSI for every 10 degree change in temperature, and tire pressure changes 0.5 PSI for every 1,000 feet change in altitude.

[soupcxan]

Thanks for the advice - it was the spare that was low.