I am getting err 40 when I turn on my 7d

[Mykolas]

Hi stefflundstrom!

Thank you for the post.

"Err 40" indicates that a malfuction related to the power source has been detected.  Please follow these steps to attempt to resolve the error:

1. Power down the camera.
   
2. Remove the lens, battery and memory card.
   
3. Let the camera sit for 10 minutes.
   
4. Use a soft microfiber cloth to clean the contacts on the battery and inside the battery compartment.
   
5. Reinstall the battery.
   
6. Power the camera on.
   

If the error still occurs, your camera will need to be serviced.

To start the repair process, you'll need to complete a Repair Request on our website.

[jcllorca]

I get ERR 40. I get it when the camera has been off for a while and it wont turn on. I have tried your suggestion and still gives problem. However, I take out the battery and it works again.
It did the same when It had the grip on.