[Corsa C 2000-2006] emissions light

[jamie j]

hi there im new to the group and have just bought a corsa c 1.2 16v sxi ..... just recently had a full service.. all good no probs... but have just had what i believe to be an emissions light come on... so the manual says? now ive contacted the previous owner to ask why this light would of come on... and he said he had a full stainless steel decat system made for the car and had to change it back to cat to pass mot .... now the car was sold to me with cat back on... and he believes this is what triggered the light before? so what am i supposed to do? i been told lambda sensor , ECU, cat manifold alsorts what do i do before putting in garage to get stung again?

[Taurus]

Welcome. There are a number of things that could cause the emissions light to come on. Personally, rather than messing about with so many possible causes I prefer to put the car onto Opcom and monitor the live data. That usually points you in the right direction pretty quickly. If you own a Vauxhall and have a laptop it's a piece of kit that will pay for itself many times over. You can buy on ebay, or I get it from this chap Vauxhall-Saab Op-com Diagnostic Solutions - Home. (Not the cheapest - but if you hit a problem he offers aftersales support which some people have found useful when they struggle to set it up.)

Or if you say where you are there may be someone local who has it and can put it on the car for you.

If it's had the old exhaust & cat put back on it's possible they've used jointing compound which can contaminate the lambda sensors - that can cause the emissions light to trigger. Check the exhaust isn't leaking anywhere - put a damp rag over the tailpipe and check for any signs of blowing.

[jamie j]

thanks for the reply 98% its the lambda sensor its also smelling rich with fuel???

[Taurus]

Over fuelling could be a dud coolant temperature sensor - cheap and easy to replace (they don't always throw a code when they fail) - usually you'll find it struggles to start hot when it's too rich.

[jamie j]

Had the front sensor replaced.... got 5 miles down the road... and the engine light came on again. Drove back to the garage that fitted it and the same error came up on diagnostics catalytic emmisiions below threshold bank1. Now do I change the centre lambda sensor also?

[Taurus]

I doubt that will sort it. Remember that the Lambda system is a feedback system. If the exhaust gases are out of parameter then the Lambda will show a fault - but it's not the sensor itself, it's whatever is causing the gases to be out of parameter. Hence why I suggested reading the live data to see what's going on.