After having the time chain gasket changed on a 3.3L '95 Intrepid the engine is completely dead. Testing produced Code 11 below. 11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. Can cause the engine to stop working entirely with no limp-home mode. What do I have to do, to get the engine running again? All advise gratefully received. Amos PS what is 'Hall effect'?