You already told us the TPMS warning light functions because you see it light up when you start the car. Have the Tire Shop scan your wheel sensors before they start any work. Would be interesting to learn if the Tire Shop finds any wheel sensors defective. If so, the TPMS warning light should be lit. For the TPMSs warning light to be out, all the wheel sensors should be functioning properly. And since the TPMS wheel sensors are the original OEM versions, the TPMS Module would not have to "re-learn" a wheel sensor if a defective one mysteriously restarted sending a signal. I am not aware of anything else that would trigger this situation. (Note: There is the possibility that low tire pressure in any one tire would trigger the warning light. But it would amaze me if you had a tire with low air pressure for 3 years!)

Your follow-up on this will be interesting to hear for many of us. Later,