Canon3100 with code e000020-01a9 and -02a9 and -03a9, turned off. checked drum, fuser seems ok help

E020 Drum/Developer-related error
XX=01:Y XX=02:M XX=03:C XX=04:K XX=00:Any color
XX10 In INIT control of the initial setting,
SGNL is less than 62. Clean the ATR sensor window, Check on attachment of the developing unit, Check on a break
in the ATR sensor, Replace the ATR sensor
XX11 In INIT control of the initial setting,
REF is less than 62. Check on a break in the ATR sensor, Replace the ATR sensor
XX12 In INIT control of the initial setting,
SGNL is 960 or more. Check on a break in the ATR sensor, Check on operation of the shutter, Replace the ATR sensor
XX13 In INIT control of the initial setting,
REF is 960 or more. Check on a break in the ATR sensor, Replace the ATR sensor
XX50 When density data is computed using
SGNL value and REF value in ATR
control, REF becomes 0 due to backup
data corruption.
Clean the ATR sensor window, Check on
attachment of the developing unit, Check on a break
in the ATR sensor, Replace the ATR sensor,
Replace the DC controller PCB
XX51 When density data is computed using
SGNL value and REF value in ATR
control, the sensitivity coefficient
becomes 0 due to backup data
corruption.
Replace the DC controller PCB
XX81 P-SENS-P is less than 255 when a base
(drum face) of patch detection is read
out.
Clean the patch image reading sensor window
XX90 A computation result of patch reading in
patch detection is less than 16. Check on attachment of the developing unit, Replace the patch image reading sensor, Replace
the developing unit
XX91 A computation result of patch reading in
patch detection is 1008 or more. Check on toner leak from toner buffer in the developing unit, Replace the patch image reading
sensor
XX92 A computation result of patch reading in
patch detection is less than 42 for Y/M/
C and less than 73 for Bk 3 times in
succession.
Check on attachment of the developing unit,
Replace the patch image reading sensor, Replace
the developing unit
XX93 A computation result of patch reading in
patch detection is 522 or more for Y/M/
C and 543 or more for Bk 3 times in
succession.
Check on toner leak from toner buffer in the
developing unit, Replace the patch image reading
sensor
XXA0 In ATR control, SGNL is less than 62. Clean the ATR sensor window, Check on
attachment of the developing unit, Check on a break
in the ATR sensor, Replace the ATR sensor
XXA1 In ATR control, REF is less than 62. Check on a break in the ATR sensor, Replace the
ATR sensor
XXA2 In ATR control, SGNL is 960 or more. Check on a break in the ATR sensor, Check on
operation of the shutter, Replace the ATR sensor
XXA3 In ATR control, REF is 960 or more. Check on a break in the ATR sensor, Replace the
ATR sensor
XXA8 In ATR control, the detected T/D ratio is
upper than its upper limit (13%) 10
times in succession.
Check on toner leak from toner buffer in the
developing unit, Replace the ATR sensor
XXA9 In ATR control, the detected T/D ratio is
lower than its lower limit (3%) 3 times
in succession.
Check on attachment of the developing unit,
Replace the ATR sensor


BUT FIRST: Check the ATR SENSOR, left from the developing rotor you have an "rail" with atr sensor - vacume it!!!!! Vacum all dev units, and copier