I just bought a mag wheel to match the 4 on the truck so I can do 5 tire rotations. 2015 F-150. The truck has a full size tire on a steel wheel. Do I need to buy a TPMS module for the new wheel or is there one in the spare already?

 

There is no sensor in the spare. If you add one, you'll have to reprogram the sensors each time you rotate. Unless you have luck with not needing to reporgam, but assume you'll have to.

 

 

A thought (no actual experience) ... Having a TPMS sensor in the spare may (?) throw-off / confuse the system.

e.g. Know for storing, resetting, etc. wheels they need to be separated by at least 10'.

But then ... It may just mean that when swapping-in the spare, the sensors have to be re-trained.
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If you program the wheels for each tire, it should ignore the others around it.

 

I was under the impression they go into "sleep mode" when they have not been spinning for a set period of time. I have not had to make any adjustments after 4 wheel tire rotations and when I recently picked up a slow leak the sensor correctly identified the correct tire. If I have to re-calibrate after rotation I don't see that as a big deal. My last truck I flipped the spare so the valve stem was down & I could check the pressure occasionally. I never did a 5 tire like I should have because then I had snow tires on extra wheels. It was 18 years before I needed the spare due to a belt separation 200 miles from home on a Saturday afternoon. I could not get a new tire and was worried all the way home about that old spare. That is one of the big reasons I bought the spare mag wheel. I want too keep all the tires in use so they can be replaced regularly.