pitokhato — You've already been given excellent advice. There's nothing wrong with your TCH! Low temperatures have a huge negative effect on the fuel efficiency of all cars. Just some comments about ECO mode. There's an electric heater that can get switched on to provide cabin heat before the ICE is up to temperature, if you switch ECO off. This of course takes a lot of energy from the 12-volt battery, and replenishing this energy will use more gasoline, and make the ICE run for longer periods during cold warm-ups. Switching ECO off also uses more aggressive air-conditioning, which draws power from the high-voltage battery, and recharging it also uses more gasoline. So, ECO mode saves gas both summer and winter.

Stan