Tire pressure indicator wont go out after I put a spare on

Yes. The spare tire has no sensor.

The TPMS sensor is in a tire that is still flat. Either the system sees that it is still flat, or it is out of radio range and the system sees (hears over radio) only 3 good tires, not the required 4. So the light stays on.

Or, you could have additional low tires. But the display would not distinguish that case from the above.

 

Do yourself a favor and read the owners manual. You have a better understanding of the car.

 

Correct... in the trunk the TPMS unit is transmitting a pressure reading of about 0 psig and room temperature. But even if you took the flat tire out of the trunk, the light would probably stay on because the car is expecting a reading from that sensor.

 

i've got a related issue. light went on several days ago while the pressure is still decent (36PSI). i didn't check the spare but i understand the spare has no sensor. 6 years and 80,000 miles. does it sound reasonable for a sensor battery going kaput? it lasted for 8 years (IIRC) in my RAV4 with lower miles.

 

Some people say on the 17 in touring wheels the TPMS may experience more bumps and fail earlier. Other than that it sounds too early but it could be an outlier. If you have the Techstream with mininvci you can see the readings. Also you may have the low pressure alarm set too high (use Reset button).

 

I would make sure all the tires are set to the correct pressure and then reset the TPMS using the button. If the light goes out, the wheel sensors are working.

 

i aired the tires a bit and the light went away. the TPMS must have been reset at high values. in retrospect i should have done it before posting. sorry for hijacking the thread.