Did you have a paper jam prior to this occurring ?
i did indeed
It's a quirk of this printer that if you turn the power off and on again with a paper jam still present it will give a back door open error when you turn it on again.
That indicates the printer thinks you have a paper jam still in the fuser area of the printer.
If you open the front of the printer and remove the drum etc and make sure it is clear of any paper and then go to the rear and open the door. To the right of the fuser you should see a tab that you can pull to open the fuser cover. (see pic)
Check for anything caught in the fuser area and if found remove it.
Then put everything back and check the status of the printer. (may require a power off to fully clear)
All being well it will be back up and running.
thanks, XXXXX XXXXX done all that, and it is still saying the same thing. i'll try again.
There is a jam sensor on the fuser that if dislodged will continually give this error.
Brother have since updated the part to improve it's reliability.
i can only describe it as a long thin piece of plastic that runs from the center of the fuser to the right side.
On that bar is a lever which hits the paper as it feeds through to tell the printer paper is present. If that is broken or dislodged then you will get a solid jam or door error.
You're a star - I found that little thing, and it had come out of its place, put it back and away we go.
Many thanks for your help.
Hope it behaves itself now.
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