GTI Emissions MOT Fail

[maverick1984]

Afternoon,

Car failed its MOT on emissions today. The tester said there is 3 reasons why this could fail - Cat, Lamba sensor and anothere sensor (cant remeber what he said)

First fast idle

CO level = 0.61 %vol  (0.30 maximum allowed)

second fast idle test

CO level = 0.50 %vol (0.30 max allowed)

Can anyone advise what i need to replace from the above results?

[Adam]

Other would be MAF

When was the last service? 

[01664gti]

need to vagcom it matey and see what it shows up

[maverick1984]

Last serviced about 2 weeks ago

[Shady Pioneer]

Does you cat sound noisy? Mine does and on my last MOT I failed 1 emissions test, but passed the other two but it's gotten worse over time, so before MOT time in June I'm getting a new one put on.

[maverick1984]

Yes it does sound noisey when accelerating. i was hoping it would be sensors as cheaper to do

[Shady Pioneer]

Yes it does sound noisey when accelerating. i was hoping it would be sensors as cheaper to do

As said I guess try VAG COM first, but could be your cat, I know that's what my problem is, sounds horrid when idling, especially in the morning.

[Wayne]

I would say your cat has failed or is on the way out.

[Mikester]

Mine collapsed, and sounded like i had no exhaust.

But it still passed the mot.... but that just could be my mot tester. Who knows. lol

[Shady Pioneer]

Might be why my backbox sounds like it's a bit fecked then haha! Need to change cat asap.