I have been getting an engine warning light come up on my dash a few times this year (2006 Accord Euro manual).

I took the car to Honda and they said it was the cat converter and they reset the code.

3 months later it came up again and got it reset with the same code.

1 month after that it came up again and got it reset by a different auto electrician. He showed me the reader and it said Catalyst bank 2 degraded.

I then took the car to an exhaust place and he said that the cat looked fine and I am not experiencing any of the effects of a dead cat (power loss, rattling etc). He said that he couldn't replace the cat anyway as a standard one wouldn't fit (or something like that) and he couldn't source one that would fit (tried his suppliers but no luck).

The engine warning light has just come on again (I'm assuming for the same reason) but I don't want to just take it to honda to get replaced (they want $1200 or so to change it).

Is there any way I can see if it is just an O2 sensor that is playing up? Or is there something else that I can do?