I've been fiddling with my car today, replaced the cigarette lighter and have been wiring in a reversing camera. The car is going to a garage on Monday to fix the abs esp sensor issue.

 

I've just been wiring in a relay to power the camera and nothing is connected yet, but it may be relevant.

 

But the car won't start now! I get esp error on the dashboard and a clicking noise from under the bonnet when I turn the key. 

 

Any ideas?

Flat battery?

Yep!