EML, Catalytic converter, what to do?

phil675

phil675

phil675

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Hello there,

So my MG ZS 1.6's EML appeared a while ago, read the code and it is to do with the cat. Using torque on my phone, the first oxygen sensor reports 0.7v and the second reports 5-7v, usually sticking to around 7. I've read that the second should be around 3v, and these values are what causes the error. Driving and fuel consumption are not changed.

Now I'm not sure what to do. replacing the sensor is something lots of people do but I'm guessing its reporting correctly as it matches up with conditions for the error message. It isn't that cheap either (~£60 for part) and I don't want to pay out only for the light to come on again. If I need a new cat, that isn't too cheap either (~£200) and I'm not sure if I could fit it myself, can't be too difficult but you never know.

Some people get rid of the cat altogether but does this make MOTs difficult? And I'm guessing the light will be permanently on then :p But that seems to be the cheapest option and removes something to go wrong in the future.

I would rather spend the money on new tyres so I don't want to get in to a part swapping game with a garage. What would OCUK do?
 
You haven't got much choice really. Sensor would always be my first port of call, you've checked and it's giving incorrect values so seems a good place to start to me.

If you want to be sure, get an emissions test done (£10 tops) - if it's within range the cat will be fine. If it's only your post cat lambda and you know the cat is fine you don't really need to change it if money is particularly tight. Just get it sorted when funds allow and keep checking the codes as it can hide some serious issues when the CEL is on all the time
 
Hmm ok. I'm not too bothered about it, just don't want the MOT in April to be a failure and then be under pressure to get it sorted. An emissions test sounds like a good idea, now to find a decent garage.. :p
 
phil675 said:
Some people get rid of the cat altogether but does this make MOTs difficult? And I'm guessing the light will be permanently on then :p But that seems to be the cheapest option and removes something to go wrong in the future.
Click to expand...

as of july this year if the car came out that factory with a cat fitted it has to have it on at the time of the MOT, even if the car would still pass the emissions test with it removed.
list of changes to the MOT for 2012
http://www.theaa.com/motoring_advice/car-servicing-repair/mot-changes-2012.html
 
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If that's anything like what i'm thinking, the first sensor is the one that affects fuelling, the second is purely there to detect emissions and flags up an error if it's out of range.

Tried a new sensor? The ST's have problems with them now and again when replacing decat pipes and such like, people just end up putting spacers on them if they're running decats.
 
Think I would re check those figures, they don't sound right. The first sensor shouldn't give a static reading, it should be scanning up and down. Depends on the type of sensor but it's usually 0 to 1. The second sensor should be more or less static, that means the cat is working. It will go up and down but not to the same degree as the first.
 
Yes I reset it, twice :)

I'll plug the OBD whatsit in later or tomorrow and see what the readings are like, perhaps I've got them mixed up.
 
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