03 micra failed mot on high co readings

craig, May 2010

Another option which is well worth while and, after the airfilter quite likely, is the Lamda sensor (or O2 sensor). If you go to a company called Partco (lots of stores), it's around £30. I normally find it makes quite a difference to performance and fuel economy. This makes sense as it tells the computer that manages the mixture of fuel going in the engine what's coming out the other end. As the main sensor is located in the exhaust manifold (nice and accesible) it gets clogged up with carbon from the exhaust. Probably need a 17 & 12 mm spanner, and might need to unbolt the heat shield on the manifold (easy). The sensor sticks out. Unscrew & unplug, then fit new one (be very gentle with it). Read the instructions for tightening the new one before fitting. Needs a certain number of turns usually. Cheers Mark

Mark, November 2010

check ur airfilter is not blocked you may need to get diagnostic check on engine ecu to check oxgyen/temperaure sensors

mo, May 2010

if the emissions are only just over the maximum permitted level, you could try adding catclean or wynns clean burn to the tank & give it a good blast up the local bypass just before the re-test. also make sure the engine is up to full operating tempreture, when it's re-tested

des, May 2010