Renault trafic won't start

 ThinkingHi have a  low oil pressure light fault on dash had not used vehicle  for a week have tried 2 different obd11 scanners on it but they would not connect have serviced it with new oil and fuel filteroil filter new battery  waiting to fit a new pressure  sensor  as I had not lost any oil not sure where the pressure sensor  is? I am thinking it could be a ecu problem wiring problem not sure what to do next any help would be appreciated 

Is it the traffic that suffered with water ingress to ECU due to where it is located? Have you tried cleaning the ECU pins? 

Is it diesel?  If so are you sure you've got all the air out after changing the fuel filter?

Yes good shout Geoff, I always fill filter case up with some diesel if poss when refitting.