spare tire pressure reading

Took Jeep to get air in spare tire, sensors said was low, after got back computer inside is saying sensor or stem is damaged or missing. Could they have forgotten to connect something or damaged valve sensor? Is there someplace to check this instead of taking back. Thank you!

TPMS(Tire Pressure Monitoring Systems) can be funky at times. The systems I've had were not supposed to detect the spare's pressure. But check the pressure on your spare tire, make sure it's inflated according to the pressure on the sidewall. If you have the compact spare tire, it's inflation pressure will probably be higher than the regular tires that are on the vehicle.

(I once had a vehicle with TPMS, got a full sized wheel and tire to replace the donut, and the TPMS went crazy....turned out the new tire had to be synched up with the existing system)

I can't suggest how to test it yourself, except to check all 5 tires' pressures and have a read in your owner's manual.

If that doesn't solve your issue, my course of action would be to take it back to where you bought it and get them to handle it...especially if you're still under warranty. It might be something as simple as a bad valve stem.

I work in an automotive shop & can say that the workers "snap" off pressure stems all the time. If your getting a "bad stem" reading, i can garauntee somebody nicked the stem when mounting/unmounting the tire from the rim. I have done it also...sometimes it is unavoidable....pressure stems are a true pain in the ass! Just my 2 cents on the issue & that I'm giving it wayy later than I should be.