Originally Posted by jimbo5
Traveled from Ft Worth to Lubbock Tx last week. As I arrived at motel in Lubbock, a cold front was moving thru and the temp. dropped very quickly about 35 deg. When I left the motel to have dinner at an old favorite place, I noticed that the TPS light was turned on in the dash cluster. I looked at the tires before having dinner and all four tires looked normal. After dinner went to a Wallmart service center and had the fellow check the tire pressures. All was well with the tire pressures. I summized that the outside air temp drop with the weather front had lowered the tire air temp so fast that the TPS sensers were fooled into indicating a pressure drop. But the dash light did not go off. Next day went to a dealership for my brand of auto and asked the service guys to check the tire pressure once more. Same thing, all four tires were fine pressure wise. Two days later traveled to the north Tx Panhandle area and had a second dealer check for the TPS problem. The tech there said "First thing we will check is your SPARE." Sure enough the spare had only 21# of air pressure. Yes the SPARE tire has a TPS transmitter also.
"Ahhh Shucks" I said to myself.
So if your TPS light comes on....don't forget to check the pressure in the SPARE TIRE.
Jimbo, You didn't state what kind of vehicle you had. Some brands like Toyota and Chrysler have a TPMS sensor in the spare tire, but many other brands do not, so it's not an all inclusive thing.
A good tire shop should know if your particular vehicle was supposed to have it in the spare..