As mentioned, the manufactures don't want back yard mechanics playing under the bonnet of their cars when the dealers can charge what ever they wish to do the job. I'm glad I got out of panelbeating when I did as I remember trying to replace a blown headlight bulb on a Jappa and thinking it would of been easier to start at the rear bumper and smash my way forward to the headlight. In the workshop manual for my BMW it reads that the owner should only check items with a yellow handle, dipstick for oil, trans dipstick, powersteering dipstick, radiator overflow tank and windscreen washer tank. Every thing else refer to a credited BMW service garage. Oh and because of those three letters take a second and maybe a third mortgage out on your home please on the way to the BMW Garage.