No error codes. Only code 11. I've run all the suggested tests I could find. The inducer motor runs. The igniter ignites. The blower runs. My furnace does have something I've haven't seen discussed anywhere. When it was installed they couldn't get a liner in the chimney so they power vented it out of the side of the house. There is a wire that runs from the power vent motor and ties in with the thermostat wires. I'm not getting any power through the thermostat wires, even right at the control board. I'm wondering if the vent must power up before power is sent to the thermostat so to keep the furnace from starting if the power vent is not operating.