Tire light issue
 

I put new wheels and tires on my 2013 FR-S a while back and have been fighting tire light issues ever since. Just to be sure at the time, I put all new sensors in it (figured at 10 years old they were on borrowed time anyway).

I kept getting a blinking light at startup that resulted in a solid light. I checked all of the pressures and took it back to the tire place who ran around the car with some tool and said "must be something you did when you modified the car." Which is probably the dumbest reply I've ever heard.

Can anyone point me to a good place to start troubleshooting the issue? It's annoying to have the light on in the dash. Can I re-learn them somehow?

When you replaced the sensors, did you get them programed to the car?

You could have two reasons for the light to blink - low pressure and no sensors detected.
The case of no sensors detected you need around 20 miles of driving to start the blinking light that then turns solid and remain on until you turn off the car. Then it might start flashing immediately after the next startup or not, I never managed to figure out the pattern (this is when driving with a set of wheels and tires without sensors).
A low pressure warning should start blinking as it detects low pressure, including immediately on startup (had this happen on a cold morning that dropped the PSI enough to trigger that) and should stay on until some miles have passed with the correct pressure.

If either of the above descriptions are similar to what you experience, that might help narrow down the problem.

I'm pretty sure the new sensors were never programmed to the car correctly at this point. Is this a DIY? I don't mind buying a tool, but the ones I've seen are 200-300 bucks.

I think you need an expensive tool (or a dealer visit) for the OEM sensors, but there are cheaper tools for aftermarket sensors. There are some good threads floating around, but I never done anything with the sensors.

You can program them pretty affordably at home with a generic Bluetooth OBD reader ($20 on Amazon) and an app that can communicate with CAN and access TPMS section (Carista is one example, pay a $15 fee for 1-mo subscription)

The only problem is you need to know the TMPS ID# for each sensor, which is something you needed to have written down or provided to you.
-- They are printed on the body of the sensor themselves, so you would have to go to a tire shop and have them deflate and pull the tire away to read it.
-- If you're already at the store, you can just ask them to scan it with a TPMS radio tool and write down the ID for you. You can buy a TPMS radio scan tool, but that's just more $$

Honestly, this should be an easy job for any competent tire tech, but most of the time they aren't or just can't be bothered to help you fix it. Just life