TPMS alarm threshold

[MaverickZ71]

What are the factory-set TPMS alarm thresholds (lower and upper alarms) on a 2009 Silverado crew cab Z71 4x4 with the 18 inch factory wheels and original TPMS sensors?

 

I've never had a TPMS alarm show in the DIC until yesterday, after installing a new PCM tune.

 

The Hypertech Max Energy 2.0 programmer seems to indicate the lower threshold is set at 25 psi. Dunno if that is what the factory setting was, or not. The Hypertech will apparently let me change the lower threshold, but I don't know what the stock setting was.

 

Now I am getting DIC alarms at 38-39 psi, which I never got before. I didn't even know there was an 'upper limit' alarm, and I've seen 42 psi on the DIC readout before, when it is 110F+ degrees in summertime. Because the tires are set at the factory recommended 35 psi cold and after highway driving over the abnormally-warm weekend we just had, they warm up to 39-40 psi. I'm using free air, not nitrogen.

[Coby7]

The factory lower limit varies depending on the tire grade, my ''P'' tires are set 5psi on the lower scale and like you I didn't think there was a high end ( Normally 35PSI ). Maybe I should inflate one of them to find out. ''E'' rated are set at 7psi on my friends truck ( Normally 45PSI ) and he also never had a high alarm. You have me thinking now, I may try that tomorrow....

[MaverickZ71]

The factory lower limit varies depending on the tire grade, my ''P'' tires are set 5psi on the lower scale and like you I didn't think there was a high end. Maybe I should inflate one of them to find out. ''E'' rated are set at 7psi on my friends truck and he also never had a high alarm. You have me thinking now, I may try that tomorrow....

 

Thanks! I have the P265/65R-18 Bridgestone Dueler AT RH-S tires that came on the truck from the factory.

[ChevyTech77]

Roughly 20% is what you have to play with before the system should let you know what's going on.

[Coby7]

I wonder if your moto ''Every screw up is an opportunity not to make another one.'' is GM's moto?