When scanning codes code 0355 keeps coming up. Cant find that code in my book

Possible causes - Faulty Ignition Coil 5 - Ignition Coil 5 harness is open or shorted Ignition - Coil 5 circuit poor electrical connection - Faulty Crankshaft Positioning Sensor (See Comments Below) Faulty Engine Control Module (ECM) What does this mean? Read more: http://www.autocodes.com/p0355_jeep.html