2019 honda accord sport 1.5 6 speed manual low tire pressure warning lite on checked all tires and spare. Is it possible battery is dead all ready?
Yes and they are more trouble than they're worth. If still under warranty, take it back. If not, spend the $400 to get it fixed or put a piece of black tape over the light and get a tire gauge at Walmart.
checked all tires and sp are.
Did you check just the air pressure, or did you trigger the sensors with a tpms tool to make sure they were transmitting and operational? It could just be 1 sensor that is bad. Should not be bad after only 4 years. Hopefully you can get it fixed under warranty.
If not and you decide to replace the sensor(s) don't get the cheapy aftermarket sensors. Honda's and Toyota's don't like the aftermarket ones. for my Lexus, I got 4 factory Denso's from Amazon for $180, and another $80 to get them installed and programmed at discount tire.
Have you tried resetting it? https://www.dillvalves.com/wp-content/uploads/TPMS-PDFs/Relearns/RL-I037.pdf
What was the pressure in the tires?
What is the recommended tire pressure on the sticker in your door jamb?
It's unlikely for the batteries to be dead already.
Is this a good product to use? I thought it was a bad idea to have something plugged into the obd port all the time.