NEED HELP...no start...2000 4.0

2000 4.0

Cranks, no ignition. After turning the key to the on position, after 10-20 seconds I get "no bus" message with Check Engine Light. Checked all fuses, swapped AC relay with Fuel Pump relay as there the same, still no start. Pulled dash, pulled odometer, ensured clean connections, checked for loose/dirty wiring etc... Its been perfectly fine for 171K. Could it be a bad computer?

Bad crank position sensor?

Thanks for the link. After a quick discussion with my mech over the phone, he determined it was most likely the CPS and the symptoms are the same as described in that link, he also said go with OEM...any objections, or is there somewhere else where I know it will be cheaper/just as good?