tomseeley

I may just as well have posted this on any section of this forum, but I have a 2009 Sierra 2500HD duramax, so I'll put it here. I got a "check left rear tire pressure" message today. I had not driven the truck in a few days so the tires were all cold. I went around to check all four and found all four at 60-65 psi. The Owners' Manual specifies 60 front/80 rear, so 60-65 was ok in front but low in both rear tires. I have 2 questions: 1. What's the set point for the pressure monitor on any tire? Is the rear set for 80 psi because the manual says I'm supposed to keep the rear tires at 80 psi, for example? I'm trying to find out what pressure the monitor considers low and sends me the message. 2. Why would I get the message for the left rear but not the right rear when both tires were at the same pressure, within a psi or two?