2005 Buick LeSabre "Check Tire pressure" light is on, all pressures equal and normal

Years ago, I put two new tires on my wife’s 86 Dodge Colt. Same size, different brand. At speeds of 35-40 mph, the car started shaking badly. Once I was home, I could seen the difference in size between the tire brands. Four matching tires solved the problem.

After that, if I had to replace a tire, I always got the same brand.

Ed B.