tire pressure light comes on
Silly question but have you actually checked the tire pressure? If it’s okay in all the tires, including the spare, you probably have a pressure sensor that needs a new battery.
Battery’s in tire pressure sensors are not serviceable.
If the battery dies, the senor has to be replaced.
Yep, I paid about $85 a month or so ago for a new one. Two more to go. For me though if the system reads “----” instead of a figure, it means the sensor cannot be read.