Need Advice - Nissan Xtrail 2010 NT31 #2 Oxygen Sensor Issue

[rara+6164]

Hi,
I replaced the #2 (bank2) oxygen sensor after diagnostic test three times, however the check light keeps coming on, indicating the same issue???

[Dave]

Wiring between sensor and ECU if a new one was installed
Condition of cat? Damaged cat can also cause this if too much exhaust passes the secondary unit.

[rara+6164]

Wiring was checked by electrican, said its good??