Alright so heres my problem: i bought 2 new front tires for my 03 monte ss (225/60/16) the tires are goodyear eagle ultra grip GW-2's for the winter weather because they had low tread and took my old front tires and put them in the back (basically took the fronts and put them in the back and got new tires on the rims that were in the back and put those up front) in case it snows. I bought them and had them installed and balanced and i reset the light. Now i drive 60 miles to school and 60 back. Well i had the tires on for a day and my tire went flat (small nail in the edge) but the "low tire pressure" light didnt come on. so i brought the tire back and had it fixed for free. Well while i was on the spare comming home the "Low Tire Pressure" light came on. I figured this was normal since it was the spare. Well yesterday it came on again with the normal tires on. So i got home and checked the pressures and the right front was at 40, the left front was at 36 and the back 2 were at 32. So i checked the spec and brought them all down to 32-33psi-ish and reset the light again. Well the light came on again today. My question is why? Does my car have a tpms sensor that might be broken? If it does whats the part number? And if not does anyone know how this system works and why the light is comming on?

 

First I know it doesn't make sense but it is better in the winter to have the new tires on the rear of the car. You have the full weight of the engine and drivetrain on the front tires so they will stay better planted in the bad weather. You do not want the rear end to get loose and come around on you because you have absolutely zero control of that.

For the tire pressure, if your pressures are now fine and you are still getting the light, then you might have a poor speed sensor going bad. Those unfortunately can't be changed and are built into the wheel hub assembly.

The 2000-2005 uses the speed sensor to determine how many times a tire is spinning, if one tire is spinning a little less than the others, then it assumes it's because of the PSI difference and illuminates that light.

 

One other thing to throw out there that I've dealt with on my '04.... If you make a change in tire pressure (and the check pressure light was not active), the car may trip the light sensing something changed. Consider re-checking the tires, make sure they are properly inflated, reset the light and see if it comes back.

If it does come back, then next step is to see if the ABS wheel speed sensors are failing.