right. Under your rear bench is where the sensors plug into the loom....swap them left to right, clear codes, get it to fault, check again if it still says the same side, as before then its ecu...if the fault follows, ie swaps side ...left sensor is dead. If so there are 2 types (where it plugs into the loom) square or round. Prob square as looking at your vagcom you got the later abs 96/97?