Megane 1.6 W Reg Emiissions problem (Lambda?)

[Glyn1959]

My Megane failed MOT on emissions yesterday. Garage suggested lambda may need replacing. I priced this. I was told there are 2 one in manifold and one in cat. Each approx £100 each. Anyone any experience of this to which is it likely to be?
The emission reading at fast idle was 2.32% against legal max of 0.3%
The emission reading at natural idle was 1.66% against legal max of 0.5%
I don't want to spend unnecessarily ... who does?
Any ideas or experience of this problem?
Comments appreciated

 

[Gary_M]

Hi,

Does your 'engine warning' light come on? Normally it will if there is a lambda sensor failure.

I am not sure how to test which one may be at fault, but it is worth checing that there wiring connections are ok.

Don't rule out other possible causes of high emmissions. Some of the more simple ones to check are: spark plugs and air filter. Oh, and poor quality fuel may also contribute to high readings.

Good luck,

Gary

 

[Glyn1959]

Thanks Gary, I will check for a light warning light .. not noticed one

 

[chris punnett]

My three year old Megane failed its first MoT test at the supplying Renault dealer because the emissions were too high, due they said to the coils being faulty. After some pressure Renault replaced them free of charge as they said that there had been a faulty batch!!