Last thursday we had a check engine light came on my wifr was taking the car in then also the low tire oressure warning light came on. She took it to the dealer, they told her to bring it in next week they had no time to check it but asked if we had spun our tires in the ice and snow of course we did. They told us that set the code and there would be no problem driving it. As for the low tire pressure warning light it came on again and i checked the pressure 15 in one and 20 in the others. This morning i went and put air in the tires up to 50 like the side of the tire says. (The tires are are 20 inch nittos on aftermarket wheels i don't know the exact size on the top of my head car is still at shop) The car is readydid not have time to pick it up. The dealer called and told me the tires were over inflated and the placard on the door says 35 so that is what is seting off the warning light not low pressure. ( i also hate when people talk down to me concerning cars as my uncles were all mechanics and i was a parts tech for 5 years as well as a shade tree with some computer knowledge, and i also sold tires and mounted them.) i am wondering if this is true about the light coming on with high tire pressure(never heard this before) but when i fill the tires up light goes off. It also rides better at 50 psi than 35 . I think he's full of BS

 

Go to Nittos web site (here)and look at the sizes and specs link.All the 20"tires maxpsi is 50, so your within their specs.

IMHO If you like to ride at max that's cool, your tires might last longer if you bump it down5 psi of max.

 

The 50 PSI printed on the side of the tire is simply the MAX the tire is designed to be inflated to, not the pressure recommended for your car. Your tires are DEFINATLY overinflated at 50 PSI, and will wear faster in the center...Proper inflation pressure will vary due to factors like the weight of the car and the size of the tires. Using stock size tires you should use the pressure printed on the car's door sill. If you change the size of the tires, you need to change the inflation pressure. Here is one way to find the proper inflation pressure.

Fine a large, smooth, empty parking lot. Get some chalk, the big fatkind kids use to write on the sidewalk is best but any will work. First, drive around for a while to get your tires up to normal driving pressure. then go to the parking lot and park at one end, scribe several thick lines across your tread in various spots on each tire. Get in and drive in a straight line for about 100 feet, then get out and check the chalk lines. If the lines are more worn at the edges than in the middle, your tires are under inflated. If the lines are more worn in the middle than the edges, your tires are overinflated. If the lines are evenly worn, your tires are at the proper pressure.

 

I think everyone here is right - you're over inflated. Low pressure will cause the light to come on. Remember, if you're in a cold climate, the colder air temps will cause the pressure in your tires to be lower, too. The caddy I had (my dad left it to me when he passed on) had a GREAT tire pressure system. Not only would it light up if the pressures were not within spec, it would tell you the pressure of each individual tire - all at the same time (had a little lighted picture of the four corners of the car and their respective tire). On the highway, after a prolonged period of driving in summer time temps, the warning light/picture would come on, along with the pressure in the tires. So, I think your dealer is correct. Your pressures are too high.

dave

 

The sensors trigger on low and high tire pressures. I've run 50 PSI in my pickup tires when I had a load of gravel or fire wood but I bled them back to 35 when I got done. The extra pressure puts extra stresses on the tire carcass and shortens the life of the tire. It also transmits more road shock to the suspension components (and the fillings in your teeth) affecting their longevity.

Scamp, sounds like your Caddy had a system similar to my wife's 300m. I can go thru the menu on the EVIC and get a readout of the pressure in all of the tires mounted. If one goes below 25 PSI it chimes and automatically goes to the Tire Pressure Screen. Picked up a nail and it warned us with enought time to safely pull off and change the tire. It also monitors the spare and chimes and gives a message if it gets below 25 PSI. Wish I had it in my R/T. I think that the SRT8's used this system in 06 rather than the "idiot light" approach. I'm not sure if they still do.

Redbeard