Our 2006 4.2 Supercharged has failed MOT on emissions. Its not too high and the O2 sensors have been replaced.

The garage its been to suspect that it is the catalytic converters failing but dont know which one, so I need to get hold of two Cats for the Car.

I understand that the cats on the 4.2 Supercharged (2006) and the 4.4 V8 (BMW M62) are the same uniyts, so does anyone know on here where I can get hold of them?

Need them ASAP as MOT ends today and we are without a car.

Thanks in advance.

A code should have come up indicating which Cat is defective. Each bank has a separate code number. Have you googled for suppliers of catalysts.

All it shows on the test sheet is that the CO level is at 0.4% at Fast Idle speed and 0.813% at Second fast idle test. Limit is 0.2%
doesnt say which one it is.

Checked on Google and the only ones I can find are at Jaguer Land Rover at £942 each!

You need to put an OBD scanner on to get the data iirc it may say something like L or R bank catalyst is below efficiency. May be a P 1042 but I could be well wrong on that 🤔.

The test data sheet only gives the outcome of the test and not the cause.

Good luck with the quest for the catalysts.

Btw have you tried Keith Gott in Alton for the exhaust bits

Turns out that it wasnt the cat's that were the issue, but the O2 sensors.....

So instead of almost £3000 for new Cats it cost us £500 for two new O2 sensors.

Now passed MOT

Glad it’s sorted was that for sensors in total or just the two down stream? Ironically mine is playing up now as well 😆

The sensors were around £250 each, not sure if they were the upstream or Downstream but it was throwing an intermittent fault with I think the Bank 2 sensor.

We've since heard from 4 different unconnected people that the MOT test station it went to do not like 4x4's and do not like 'old' cars so will fail them on the slightest issue.

On its second MOT Test after the sensors were fitted (sensors fitted & MOT straight away) it failed on being 0.2% and 0.25%.
We took it to another Tester after a bit of a run to get the engine hot and it passed.

👍