Upon turning on the thermostat for the first time this fall, the furnace did not start up. I've summarized below what specifically is happening, the error codes I've received and the steps I've attempted. I am not sure what to try next to resolve this. Thanks in advance for your advice/tips.

Details of Problem
HSI lights, gas flows through all 4 burners and ignites, HSI dims and gas shuts off, flame out. After 3 attempts, the red LED light flashes 4 times.

Steps I've taken
Cleaned flame sensor- retested - no fix
Replaced flame sensor with generic part (not an exact match) - retested - no fix
Cleaned all 4 gas burners - retested - no fix
Re-positioned sensor to be fully engulfed in flame - retested - no fix

Details of Furnace and Parts
Olsen H/E gas furnace -G95V060-3 - installed in 2008
Flame sensor (original) ICP model 1380687 (replaced with generic sensor - no product details)
All wiring and connections appear "as installed" with no obvious signs of breaks/disconnections.