Please can anybody help iv got HDC fault on dash it's a fl2 07 & won't start if I put a new battery on will this help the fix many thanks Mick

The HDC fault is almost certainly a symptom of whatever is causing the non-start, rather than the cause itself.

Since you mention the battery I assume the non-start symptoms are consistent with a flat battery? If so charging the battery, or a jump start, should get the car going. If not, please tell us more about the symptoms you are experiencing.

Assuming it is the battery it doesn't necessarily mean that it's dead. There have been cases where something hasn't shut down properly, and has drained the battery overnight. Once re-started the car has been fine.

HDC fault messages are a common symptom of a low battery, and are seldom the real cause of the problem.

I had this problem as have several others and the answer may be as simple as adding an extra earthing cable.
Have a look through here
http://www.freel2.com/forum/topic16694.html

I wouldn't bump start!
It could do a lot of damage.

Better to jump start to fault find or buy a new battery if it's no good.

Ok so had new battery fitted & so far so good but if it's still ok after the weekend I'll be happy because then ill no it's not the alternater so thanks for all the advise many thanks mick

On starting, it's a major drain on the battery, a weak battery will be worse, the Haldex is linked to the electrics obviously so you get the message, same as you would with the Headlights, you don't get a message but they go dim on cranking.