Co2 emission too high.

[Meldrew]

My 1.9 has emission of C02 too high at O.4, and should be max 0.2, all other emissions ok and running very well.
Garage advised it may be the ECU mixture control , or possibly catalytic converter, how can I determine which?
Would a BMW garage be able to plug in and determine the fault, if so can the ECU be 'adjusted' ?

 

[t-tony]

Are there any engine management lights lit ? You need to get a code reader connected to the car to see if there are stored fault codes which may give a clue. The test centre should have given you a print out of the emission test results. If they didn’t go back and ask for a copy. The test machine stores all results and they can do a reprint. Take a picture and post it on here so we can see exactly what the readings were and IF they bothered to take the engine oil temperature or not.
The ECU cannot be adjusted. It is most likely the Catalytic Converter which has failed (very common on the 1.9 models) or possibly O2 sensor failed.

Tony.

 

[colb]

As @t-tony posted good code reader needed on it that can also read live data. Take a look at the fuel trims in live data high readings would indicate its running rich to counteract a lean condition the exhaust sensors are picking up as extra air may be getting in from split or holed intake boot or any of the rubber and plastic vaccum pipers across the engine. Important to check for leaks and put any found right by replacing any faulty parts. Failed Cat also a possibility if you are really unlucky. As stated earlier there is no way of adjusting the ecu its all done by the computer and the readings it gets from the sensors. Live data should allow you to view the pre and post Cat sensors so you can see what they are doing or even working.