American standard Heat doesnt kick in, Air intake partial block.?

[logsplitter]

Hey folks,
 Furnace Model AUH2BO6OA9V3VAB At 1st It lit up the blue flame but beyond that didnt heat up, I checked the continuity on Ignitor, flame sensor they werent open. I turned off breaker to reset everything, did clean the sensor with steel wool. Without closing the little door (that has the eye window) i turned it ON, It started working. I sense that closing that little door causes it to lack for intake of air & hence doesnt run. I have hence closed that little door but let the eye hole open by removing the round glass. The machine is anyway covered by the outside panel. Am i right in saying that the Intake is kinda clogging at some point of the pipe causing it lack of intake air.? Or is it something else.
CODES : Green light flashes fast (i believe its normal)
           Red light flashes twice at the start and then flashes once every 30 sec or so.   
(I hv experienced same situation in an other Carrier furnace, upon removing that same little door its been working fine for last 2 seasons.) Appreciate any inputs.

[Admin]

It sounds like you got it figured out.  Find the intake pipe outside and clear out the snow or ice.  Then you can put the burner box door back on and everything should work again.