P38A [P38] MOT Fail - Emissions

Just Japan and USA got 4 o2 sensors. Everyone else made do with 2 I think.

I think (think) the engine is OBD compliant enough to show what the o2 sensors are doing with a bog standard code reader. With the engine running they should show the voltage swinging up and down. If they're not doing that you know there's a problem with the sensors somewhere.... or something is causing the engine to constantly run rich.

I know where you can get some cheap CATs if it is them.....

Just been to the garage - they reckon the cats have been cut out and replaced with straight pipes. Pictures to follow later.
If that's the case - please do share where I can get some replacement ones.

Should the O2 sensors be pre-cat or post-cat?

They should be pre. Just the two of them.

I went to Cats2U for mine…. £156 delivered.

You have to be careful you get the right one though. They changed a bit over the years. Biggest change is GEMS to Thor. The hole and thread size for the o2 sensors is different.

Thanks , I'll take a look.

Here are the pictures, does this support what they're telling me?