My battery went flat so i Replaced the battery, now I have no dashboard lights and a steering fault Keeps coming up on dash . Nothing happens when I turn the key ? Radio working, Interior lights come on ..
You replaced the battery or auto service place? Auto service place should have known better. A batter tender (minder) is needed. Check with Rennlist Porsche forums, more techies there.
Unfortunately a visit to Porsche dealer might be necessary.