Cat inefficiency warning light

[bertieg]

about 6 months ago i had the EML come on. fairly certain it was code p0420, which is catalyst system efficiency below threshold (

i turned the light off, and it has not come on again since. is it likely to be a worn cat, or just a false reading? i would have expected the code to come back if the cat was knackered?

my MOT is due fairly soon, so it would be nice to know whether it is probably okay, or if the cat is definitely knackered and its just not flashing the light up

 

[Beasley Clio182]

6 months ago? I wouldn't worry if it hasn't come back ! Put it In for MOT before you go spending any money !

 

[Zeitgeist0190]

false reading from dodgy sensor perhaps?

 

[Bainzy93]

If it comes back on every few months it'll probably be the Lambda Sensor on its way out mate. If not, then don't worry about it