How does "Low Tire" indicator work in Buick Century `99?

I thought there is some sensor connected to the tire that measured the perssure. But there wasn't or maybe it was missing!

This indicator stays on forever. There was a reset button for it in the fuse box, but it did not do anything.

Any idea?How does "Low Tire" indicator work in Buick Century `99?The computer calculates the low tire pressure by the wheel speed sensor. Speed sensors are on each wheel of this model and are also used for antilock brakes. The sensor is mounted in the wheel hub/bearing assembly. It calculates it by counting numbers of wheel rotation. A low tire turns at a different speed(more revolutions) than the others.

If your antilock brake light is on due to a broken circuit in the sensors your tire pressure monitor will not reset.How does "Low Tire" indicator work in Buick Century `99?
I`ve been trying to figure that one out for years.I`ll check back to see if any body else knows.How does "Low Tire" indicator work in Buick Century `99?Did you actually check your tire pressure or did you just try to reset the system?



The system on that car does not measure tire pressure at all. It measures the number of times the wheels rotate using the ABS/Wheel Speed sensors, not a pressure sensor inside the tire and wheel assembly. If one or more tires is over or under-inflated, if you have one or more tires on the car that are the wrong size or if you have tires of mis-matched brands or dramatically different amounts of wear that can set off the system.



Check all your tire pressures when the tires are cold - preferably in the morning and before you do any driving. Make sure the pressures are set to exact what it says on the Vehicle Information Tag inside the drivers door frame (30 psi front and rear), then check to make sure all the tires are the correct size (P205/70R15 95S) and have similar amounts of wear.



Now you can reset the system following the procedures in the owners manual.How does "Low Tire" indicator work in Buick Century `99?
The sensor is inside the tire, it's part of the rim. If it isn't working then it could either be the sensor or the electrical coupling to the rest of the car. Since the tire rotates, there is no wire going to the tire, the sensor transmits a signal either via radio or by a magnetic pickup on the suspension.



The possibilities are the sensor is damaged (by an incompetent mechanic when replacing/rotating the tire), or the pickup is malfunctioning. It's also possible there is a wiring fault somewhere between the wheel and the vehicle computer.How does "Low Tire" indicator work in Buick Century `99?Some cars have the sensor in the valve stem. It reads the tire pressure and sends the signal to the computer. That's why some dealers will tell you that you have to use the same stems if putting on new wheels. Not sure if the Buick works this way.