Can't take outdoor shots

Hi, I have borrowed my mates Canon EOS 7D fitted with a Canon EFS 17 - 85mm lens. I have it switched to auto focus but everyan time I try to take a shot outside the error code 01 comes up telling me there is a communication fault between the lens and camera! The weird thing is that I can take shots OK indoors but as soon as I try to take an external photo I get the error code come up! Any help would be appreciated as I have borrowed the camera for a holiday in the Scottish Highlands and not being able to take outdoor shots is not helpful to say the least!