LexRexBlue

It's frigid outside and the 400h is fine when the engine is cold. After a few minutes warm air comes out of the vents. Then, when the engine is warmed up it only sends out COLD air. It doesn't matter what the temperature is set on. It's going to send me to my IS to drive in the cold. Brr-r-r

rcy

Could be a few things - faulty engine thermostat (does your temp gauge move as the vehicle heats up?)

Could also be the associated bits and pieces in the dash (blend door, motors etc. that are supposed to allow a certain amount of outside air to mix with the hot air from the heater to give you warm air.

Might also be a sensor of some sort. Is your outside temp display showing the right temp? If it's not working right and the system thinks it's 80f out it's not going to give you any heat, assuming the climate control system uses the outside temp gauge for data. There is also a temp sensor in the dash (look just below where you insert the key and you'll see the little grill to allow air to flow over the sensor). If this sensor is not working it may also mess things up.

Lots to consider. Hopefully something easy and cheap for you though.

I know the dealer can pull codes from the climate control system that might tell them if a sensor is bad.

LexRexBlue

Thanks much. When its warmer I'll bring it into the dealer and let them check it. Meanwhile I'll stay warm in the IS. It's amazing how quickly the little car warms up and stays warm!