Rickard1982

It's a diesel scooter

dls91

Light seems to be coming on a bit more now is this a case of just replacing the primary sensor on the cat?

Rickard1982

Yep

BenRNBP

Technically, it's the secondary sensor on the cat but yes the one on the cat. But before you do that might be worth an ECU reset, a check for exhaust leaks (doughnut seal on downpipe to cat) and possibly an investigation into why it might be over/under fuelling - e.g. maybe a duff injector ?

I find logging and looking at the long term and short term fuel trim values can give you a clue as to what's going on. I use the Android Torque app and an eBay BlueTooth ELM327 that looks like this one http://www.ecutool.com/Bluetooth-ELM327_3542.html

Here's a couple of articles on fuel trim diagnosis;
http://www.underhoodservice.com/fuel...r-performance/
http://www.easterncatalytic.com/educ...agnostic-tool/

dls91

well everything was fine before fitting the berk high flow cat. now it seems like both sensors have given up after fitting