Tire pressures round 2

rjgvt · March 7

A while back I set my tire pressures to 55 psi front and rear. Door sticker is 60 psi Front and 70 psi Rear. I recently had my truck weighed and decided to set them to 51 psi for all 4 tires with a little leeway if the temp dropped. After I got done and started up the truck, I got an email and text from Onstar to add air to my rear tires. I ignored it as the TPMS sensor error has not come on yet. It's been 3 days since I adjusted the pressures, no TPMS error. If the tires are warmed up and the rear pressures are 55 psi or more, no Onstar alerts.

The myGMC app shows orange if the front tires are under 55 psi and the rears under 60 or 65 psi. Not sure what it takes to get the TPMS error to come on but not going to lower the pressures any lower than 50 psi. The ride is good but as the average temps rise, I will watch the tire pressures and not make any adjustments until it gets over 55 psi.

bruceb58 · March 7

It's too bad GM doesn't have something like Ford's Forscan to change the limits. This would be an easy change with Forscan.

rjgvt · March 8

I can change the parameters through the OBD II with an Autel TS508 but haven’t done it yet since I don’t get a TPMS error on the DIC. When I did do a “read” with the Autel, it read -17 psi for both front and rear. I was expecting to see actual pressure readings like 60 and 70 psi. Not sure if it’s looking for -17 psi for the TPMS error. One day I’ll change the parameters and see what happens.

bruceb58 · March 8

I have the Kingbolen K10 scanner. When my truck actually arrives, I may play with it.

rjgvt · March 9

Got my Autel TS508 out today and attempted to change the tire pressure placard values to 60 front and 60 rear using the OBD II cable. I chose one of the 2023 GMC Sierras. It forces to do both. It said it was a success but when I "read" the parameters with the Autel, it still read -17 psi for front and rear.

Decided to do an update to the Autel, there were several. Before the update,it only showed GMC Sierras made in 2023 or before. After the update, it now shows 2024 GMC Sierras but they don't show the tire placard option. I went back out to my truck did the read function again and it read 60 psi front/60 psi rear. myGMC app updated to Front 60 psi / Rear 60 psi. The tire pressures on the app were orange as three of the values were less than 55 psi.

Changed the tire pressure placard values to 55 psi. Was able to read the values with the Autel right away. The update did the trick. Drove my truck down my driveway and back in the garage. myGMC app updated and no more orange tire pressure values.

EDIT: Autel's website says that all vehicles do not support the tire pressure placard value change function. Glad mine worked.