What's the most common Rheem furnace error?

What's the most common Rheem furnace error based on technician reports and owner forums for models like R96V and R98V is error code 201 or 3 flashes indicating flame failure or pressure switch failure, and igniter failure causing error 201. Most common error is flame sense failure where furnace lights then shuts off after 5 seconds, showing error code with 2 flashes or 201 on control board LED visible through small window in lower panel, caused by dirty flame sensor that is metal rod in front of burner that detects flame, gets coated with carbon and oxidation after 1 to 2 years, preventing detection, fix by cleaning flame sensor with fine sandpaper or dollar bill and reinstalling, costing 0 if DIY or 75 to 150 dollars for technician. Second most common error is pressure switch failure showing 3 flashes or error 45, where pressure switch does not close due to blocked vent, clogged condensate drain for high efficiency furnace, or failed inducer motor, causing furnace not to start ignition sequence, fix by clearing vent and drain. Third is igniter failure showing error with 1 flash or 201, where hot surface igniter cracked after 5 to 8 years does not glow orange, causing furnace not lighting, replace igniter at 100 to 200 dollars. Fourth is high limit tripped due to dirty filter causing overheating. Always check filter first, then flame sensor, then pressure switch.