knock sensor

I have a 1997 villager/quest 140000 mi. It stopped dead in the road while driving and won't start. The OBD 11 flashes 3 long 4 short indicating a problem with the knock sensor. I have voltage at the conector but no change in reading when engine is hit with a hammer. Is it possible for the knock sensor to disable the engine if it goes bad. I understand that it controls the timing. when cranking the engine sounds like it's trying to run for a couple turnes after letting of the starter. Should I be looking at the timing belt? The engine has spark and spraying cleaner into the intake has no effect. I'm trying to find an easy answer before I take the top off the engine to replace the sensor. Thank you in advance for your attention to my problem.