My '15 XLT tire pressures are all over the scale, and change almost every day. I adjust them using a calibrated tire pressure gauge to exactly 35 PSI, and the next morning they will vary as much as 3 or 4 PSI per tire. On some mornings, a tire that read low will be higher and vice versa. The truck is garaged nightly. Is this a sign of failing TPMS sensors or some other problem? Thanks in advance, John

 

Are you reading them after start-up or when you've driven a few miles? They need to move after starting to update.

 

After driving a couple of miles, the air pressure will go up around 1 or 2 PSI. I filled them all last evening after I put the truck in the garage, all were at 35PSI. This morning prior to driving, the tires were at LF-32, RF- 34, LR- 32 and RR-33. They will maintain these pressures when I check them weekly. I can understand that if filled on a warm day, the pressures will be somewhat lower in the cool mornings, but why are they all different after filling them all to the exact same pressure?

 

Have you checked the TPMS pressures immediately after checking the tires with your gauge?

 

This is what I do:

Pull in garage and add air until they all read above 40 psi. Next morning (6 - 7 am) I use a quality air gauge and bring all four tires down to 35 psi. This is “35 psi cold”, as stated on door sticker.

Once you start driving each tire will change psi depending on turns (left or right) as well as which tires are in the sun more. If you check the next morning, before driving all should be at 35 psi cold again.


I see front tires gain 1 psi simply because of turning and driver side gained 2psi because sun was on that side.

When TPMS go bad you will not get a reading on that tire.