Is the indoor blower running?
The control board in the furnace only does fault codes for heating, and there are several LED's on the board, only one is for fault codes.
If it is flashing once every 20 seconds or so, it is indicating normal operation with no call for heat.
If the fan is running, and the system has a 5 ton blower, the LED flashing 21 times between pauses may be the CFM indicator.
Turn the system off and call a pro.
If more government is the answer, then it's a really stupid question.