What does no motor error code mean?

Are you saying you used to see a code light and it is not longer seen? I would start by confirming that there is power to the control board. Which furnace do you have?

Thanks for response, there is a green light on, the red light is off. If I shut off power then restore power, both green and red light are on, furnace starts to cycle then about 15 seconds in red light goes out, motor shuts down, only green light remains on. The error code (one green constant light) means "no motor". It is a Kelvinator furnace installed last summer

Is the motor you refer to the inducer motor that circulates combustion gases through the furnace or the blower motor that circulates heated air through the house?

"installed last summer" so its still on warranty, right?

Make sure you have the gas on going to the system.