Can anyone help my gimbal totates freely but error code 40002

Error code 40002 Gimbal stuck.  Usually prompts pilot to Check whether gimbal cover is removed and ensure gimbal can rotate freely. Happened to me over a year ago and I used DJI Assistant 2 and refreshed firmware and error went away.   

Hi there. Thank you for reaching out and we do apologize for the inconvenience caused. Can you please confirm if the drone experience a hard landing? You may refer to the troubleshooting steps that DowntownRDB provided on post #2 to see if the issue persists? In addition, kindly please check if there is a dusk or debris on the gimbal, clean those and restart the unit then check if there's any changes. Please keep us posted. Thank you.

I haven't crashed.it ..  I've hadn't used it un ages and was fine when I had put it way

I've owned it for about a year and only flew it about 8 times

Cover is removed sometimes, says gimbal overload?

How do I clean it do I just blow it  I does rotate easy as when I switch it on it turns every direction