EML light

27th April 2012, 20:25

hi, ive got Another eml problem, bought a new manifold for my mk 2 vtr it came with a lambda sensor in it i left the lambda in and fitted the manifold, then a roughly 2 weeks later the light came on then scanned it with my odb2 and came back with the code P0420 (Catalyst System Efficiency Below Threshold Bank 1), i changed the green lambda sensor with a brand new one, now roughly every 50 or so miles the light keeps coming on and flashing the same code up,

the blue lambda is new practically brand new and both are pretty clean. and the cat is only 2 and a half years old

anyone know whats causing the light to keep coming on? or sugest anything
thanx

27th April 2012, 20:44

Did you clear the code from the ecu?

27th April 2012, 20:56

yes cleared, then came back on with the same code, done this a couple times

27th April 2012, 21:04

It's telling you the cat is foo-foo'd, it might only be two and half years old but if it's a crap cat then it's likely its gone.

27th April 2012, 21:37

just keep clearing it and ignore it mate. the post cat lambda will flag up the cat being below efficency even if it's only running at 95% efficency.

take it to a garage and ask them to do an emmissions check on it. if it passes ignore it.

mine comes up every no and again with that code but it's gone through emissions without problems. infact it went through it's last test just after i rebuilt the engine. so there were oil all over places that don't normally get oiled.

28th April 2012, 21:15

If you have a decat pipe on this will cause the problem as well

29th April 2012, 20:26

did have a de-cat on but went back to the cat for the mot been like that since