Brother HL-4040CN, HL-4050CDN, HL-4070CDW Service Manual page 41

Error code 81
Calibrate
Calibration failed. See Troubleshooting chapter in User's Guide.
Incorrect density sensor measurement value when implementing calibration from the control
panel.
Error code 82
Calibrate
Calibration failed. Press Go, and try again.
Density patch measurement is not completed normally when implementing calibration from the
control panel.
User Check
- Check if there is a scratch, dirt or the like on the belt unit. If there is, replace the belt unit
with a new one.
- Check if the genuine toner cartridges are installed in the correct order of colors.
Step
1 Density sensor shutter
catching on some position
2 Harness connection failure of
density sensor holder ASSY
3 Density sensor failure
4 Transfer HVPS PCB failure
5 Engine PCB failure
Cause
Correct catching of the density sensor shutter.
Check the harness connection of the density
sensor holder ASSY and reconnect it.
Replace the density sensor holder ASSY.
Replace the transfer HVPS PCB ASSY.
Replace the engine PCB ASSY.
1-24
Remedy
Confidential