my 2.0 petrol bug engine managment lights on, i plugged a mates obd2 reader in and it comes up with po135 and po134, number 1 O2 sensor faults, i have reset them but they come back on, how do i know which sensor is number 1. can the sensors be checked?

 

It is the one before the converter.

 

found it, i had the cat replaced recently and looks like they may have disturbed it as it was almost hanging out. removed it and it was filthy, gave it a wipe and sprayed some evaporating solvent into it gave it a blow to dry it and hay ho, all good, fault code not come back after a 5 mile test drive.
thanks for the reply.