P0420 check emissions error

[col85]

Anybody know much about this error?

Keep getting the error message, and engine light coming on when doing 60-70 on the motorway using cruise control

Ive seen the other thread on this but was wondering if anyone has been to a garage with this error?

Im looking at replacing the post cat o2 sensor but before i do just wanted to see if anyone else has advice on it?

cheers

 

[deadmau5]

Is your exhaust and are all the cats standard?

 

[col85]

yeah sorry totally standard. using vpower too if that makes a diff

 

[deadmau5]

I would guess it would be a faulty O2/Lambda sensor then. Maybe try swapping around some of the sensors and seeing it that makes a difference before you buy a new one.

 

[col85]

what about putting in a decat, therefore getting rid of the sensor alltogether?

 

[Foxspeed]

what about putting in a decat, therefore getting rid of the sensor alltogether?

a de-cat gets rid of the "cat" not the sensor....no sensor = emissions light on all the time = mot fail.....

the 197 has 2 co2 sensors and both are different

 

[col85]

so if you decat you have a constant engine light on?

 

[Foxspeed]

so if you decat you have a constant engine light on?

no - as a de-cat pipe keeps the sensor(s) and the 197 has 2 cats as such so for the majority of the time the light stays off...

the whole point of the sensors is to monitor air/fuel ratio so when at the right conditions the injection can be adjusted to produce as low as possible tailpipe emissions - the second sensor sort of monitiors the first one to make sure its making the cat work in its most "efficent" range

 

[col85]

ah i see.

So if it is the cat thats the issue decat is an option rather than replacing the cat

 

[Foxspeed]

ah i see.

So if it is the cat thats the issue decat is an option rather than replacing the cat

it is but a sensor is cheaper than a cat....so you need to find out why its putting the fault on and then go from there

 

[col85]

it is but a sensor is cheaper than a cat....so you need to find out why its putting the fault on and then go from there

yeah ok

its itermittant atm, went 2 weeks without it, came back on for a few hours then cleared itself. week later its back on :@