So I'm about 3 weeks into owning this 04 Sierra, and earlier this week I bled some air off the tires because my son had aired them up to about 45 by our gauge, which turned out to be 50 according to the truck. So I dropped it down to about 35 on our gauge, (new one) and the truck was reading them at 33-34 cold.

Tonight after work I get to the truck and get a warning for my right rear and the truck says it's at 32. Truck said the right front was at 31, but it's not highlighted like the right rear. Checked the tire and gave it a good trucker thump, and it's fine, drove home, shut down the truck a few min and restarted, same result, tire pressures were up a bit after the drive, right rear at 33, right front at 32, but it's giving a warning for the right rear. Both left tires indicated at 33 or 34 I don't remember.

Anyone been thru anything like this before? Know what gives? I'll prolly add a couple lbs of air tomorrow, to see what that does, but I'm certainly scratching my head on this one.

 

Curious what does your manual say pressures should be? System would likely be set to those specs. Still stock wheels/tires?

 

Recommended pressures are printed on a sticker in the door jamb.

 

Stock rims tires are 275-60 r20 come stock with 275-55 r20.

Door jam sticker says 32. Bumped the pressure up to about 45, no more light/add air warning. This morning it started giving the same warning for the left rear if I remember right, and showed a reading of 32-33... I'm scratching my head as to why it would pick out 1 tire to warn on when others were the same or lower.

Sidewall says cold air pressure 65....

 

Strange indeed. It shouldn't complain about being 1lb off. BTW, sometimes there are different pressures stated for front & rear axles.

Anyway, perhaps the TPMS is calibrated for a heavier truck.

Sidewall states the tire MAXimum pressure rating. 65psi would feel pretty rough, and the tires probably wouldn't wear evenly.