Three days ago, the TPM came on notifying me that the front left tire pressure was low. I then drove to the nearest gas station to check the tires and it was at around 25psi and around 26psi on the right front. Don't know why, but I did not fill it back up to 29psi per the manual.

Anyhow, yesterday, the TPM came on again so back to the neares gas station. Right before I put the car into park, the warning icon on the dash and the message on the I-drive screen went away. I then proceeded to fill the front tires to 30psi but I did not have to reset the TPM. Now, I am totally confused as to why the TPM came on. I did a visual check of the tire (had the wife back the car out slowly while I looked at the tire) and found no nails/punctures.

Questions are:

1. Is there a minimum tire pressure before the TPM goes off, say below 25psi?
2. Why did the TPM reset itself?

 

Not that I've used the newer TPM system but my suspicion is that the pressures went up due to the tires getting warmer from driving around.

All tire pressures should be taken "cold" for accuracy. Once you drive around a bit, the tires get warm (due to friction) which heats the air inside them and results in the tire's air pressure rising (due to physics).

 

Stock rims?