What is the Er001 message

[Canongirl]

I went to use my camera the other day and got this message: Er001 lense can not communicate with camera. Clean lense. I took off the lense and cleaned it and tried it again, camera took 2 pictures and did the exact same thing. What is causing this? How do I fix it? I should mention it is a Canon 7D camera

 

[basroil]

If you cleaned the lens contacts (about a half dozen small gold rectangles) and mount contacts (about a half dozen small gold pins) with alcohol and it still has issues, it could mean lens or camera damage.

If it indeed is damaged, your first step will be to determine if the issue is with the lens or camera (easy if you have multiple lenses and cameras, if not ask a friend or visit your local camera store), and send it in for repairs. I would not suggest you try to fix it yourself unless you are very comfortable with reverse engineering.