(T) 2008 1.2 petrol - replacement catalytic converter?

Well, I got some interesting news from the garage. According to them, there are no OEM catalytic converters available in Europe, which I find incredible. Are there really none? According to them, the ones being sold are not compatible with the 2008 1.2 petrol, though didn't say how.

According to 7zap, the OE number is 51846634, and I can find those for sale in a couple of places. But is it really not compatible? I could of course try a used cat from a scrapped car, but there would be no guarantees it will work (reduce emissions).


The car is failing the inspection due to emissions, and if I can't get a working cat for it, it would basically have to be scrapped just because of emissions, which is very silly as otherwise the car is in fairly good shape.

According to trodo.fi , that oe number is compatible with 1.4 (199AXB11, 199AXB1A, 199BXB1A, 199AXL1A). You could aswell send them your VIN code and let them decide which is the right part for you.

Beware that it might not fix long term emission issues, if the catalyst was damaged by poor engine condition. Catalytic failure at such low mileage is a result, not the actual cause. Also remember to buy exhaust manifold studs and gasket.


It may very well be that the garage uses original parts only which start to be limited on cars over 13 years of age.

Edit: Some people with poor cats just do italian tuneup and put either fuel system cleaner additive into the tank or fill the tank partly with E85. I don't know how much of E85 would be too much (maybe 1/4 of a tank??) but certainly it's undetectable in the test and has improved emissions. Just google if you find topics on how ethanol fuel can infact make your car pass the test. You'd need to drive around for awhile though.

Definitely work running a good fuel system cleaner with a low rank of fuel and giving a good hard run




What part of the emissions test is the car failing on?


For example if like UK mot they do a lamba test this is unlikely to be caused by a failed cat w

BM Catalysts claim to be able to provide them. For example: Link

Personally as above I would make sure the engine is running well and perhaps replace the lambda sensors too

If you don't already it's worth getting MES or AlfaOBD

CO % at "high" rpm (I think they use 3000 rpm) was at 0,36 and the max allowed is 0,2

The other measurements:

CO2: 14,2
HC ppm: 43
O2: 0,54
Lambda: 1,014

As suggested in another thread, the O2 value is a bit high, but this car also failed the same CO% emissions check last year, where all the other values were normal. A second attempt passed though. I ran the cat really hot each time (~20 minutes on the highway on 3rd gear @ ~4000 rpm before the tests).

I do have AlfaOBD, but no warnings/codes have appeared (it's also part of the inspection here). Is there something non-warning-like I could check. The lambda voltage was mentioned in another thread - anything else?

Question - what temperature is your engine running at?

What I'm wondering is whether your engine is running at a low temperature (bad stat or something like that) which affects your CO readings and a good high speed run would help

During the inspection, they get the engine hot before starting the test. I presume at least to operating temperature. The engine also runs at normal temperature in normal driving, ie. doesn't run cold or hot - the meter always stays in the normal position, but I can check with AlfaOBD next time if I can get the actual temperature reading.

I had alarming co 0,1 and minor air leak with some broken manifold studs and leaky exhaust manifold gasket. Somehow it may fool the O2 sensor to enrich the mixture. Check fuel trims and under the heat shield for broken studs and leaks.

I swear by cataclean, put a bottle of cataclean in and give the vehicle a good hard drive.

I'm intrigued by this stuff.
Can you explain how it gets through the normal combustion process without burning up, so is then able to do whatever it does to the catalyst? I've not found any explanation on their, or any similar product's websites.

Aye, it’s an additive, a questionable potion at that.

Sorry mate I aint got a clue how it works, but I was worried about my Mrs 1.2 8v GP emissions because they just about passed on Dec 2019 MOT,

On Dec 2020 MOT I added a bottle of cataclean and the readings were a lot lower.

OK, its questionable, does it work, doesn't it work. The reviews are really good for this stuff. Im skeptical myself with these types of additives but this does work.

I think it's less to do with cleaning the catalyst but more they the acetonee and xylene burns cleaner


That being said I bet acetonee will burn hotter then petrol so may have s effect to help clean the catalyst

Well, the car (just barely) passed the emissions test on a retry. Had a chat with the mechanic and based on the live values he was watching on the emission tester, he was quite sure it is due to broken/worn-out lambda sensors (only 143k driven - according to Fiat the replacement interval is 160k!), and because the CO % did drop to very low values (even down to zero after 4200 rpm -> 2400 rpm), he was quite sure the catalytic converter should still be OK.

So I will replace the lambdas, and we'll see how the car performs. The next inspection won't be until next year though.