Get F2-40 error on sharp ar-5520 Im a newbie in

How are you , this problem occurs when there is very low toner concentration on the unit or low developer.
solution

1. Replace a toner cartridge and make sure it is smoothly running as some come with hardened toner or
2. Replace a new developer which is Sharp Ar 205 dv Check that the toner motor is rotating well

Get f 2 tuner caridge repace or tuner catridge chip replace your reset code below #-int-c-int& entering the commend; core code-home-subcode-home 10 ,tonermotor operation,14 trouble cancel (except for u2) 16 ,u2trouble cancel.20, 01, maintenance counter clear ,24,07drum counter clear,25 ,oi,10 main motor check,42,01developecounter clear

ATC sensor abnarmality