C43 AMG MOT fail on emissions HELP

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Jan 31, 2016
North West
W202 C43 AMG

I had my MOT today on my W202 C43 and failed due to emissions. I have had a stainless exhaust with middle CAT and box delete done about 3 months ago the CATs were past it anyway.

Anybody in similar situation is there any fuel additive or other technique I can use to get through emissions.
What were the readings? Which failed? No2, Co or lambda? You should have got a test result sheet back with the mot fail

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I had the same exhaust mods as you have on my C43 and it would fail the emissions if it hadn't been used regularly. As it was my weekend car, so I just used it for the commute for a week before the MOT and it would pass no problems.
my car is a daily driver so used almost daily
according to MOT certificatedialed due to excessive CO but no reading given
I will add some cataclean and go for a longish drive before retest

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Are the lambda sensors working ok?
Both my pre cat lambdas are faulty and no engine warning light, it's worth getting them checked with a diagnostic machine.
Did the retest failed again due to CO 0.6 should be 0.3 need to check lambda sensors now.

I think going down the CAT delete route these days is potentially going to make things difficult at MOT time
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Are they using a probe to put in the tail pipe? Excessive CO is probably cats as their function is to turn CO to CO2. If you're not getting a check engine light and they are using a probe then there's your problem.

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