Possible Cat Replacement?

[boomerbang2006]

Ive had a engine management light on the dash for a week,so i bought a code reader as i was fed up with paying x amount everytime i went to the garage.Plugged it in and got the code "PO420" and according to the book it says "catalyst system efficiency below threshold.....bank 1.

Please can someone confirm for me that its the cat,i had a new lambda fitted 2 months ago(number 1).Thanks.

 

[jenic]

If you search P0420 there are quite a few threads on this.

Could be a lambda sensor, or could be the CAT.

Maybe swap the lambdas around for a short period and see if the code changes?

 

[boomerbang2006]

That sounds easy enough to do,ok,thanks.

 

[MartinR]

I had this code pop up the day before i changed the plugs,ht leads and coil pack.it has never come back on in 6 months!! plugs etc sorted it out

Tbh though get some diagnostics done as it can be many things causing it!

 

[boomerbang2006]

I did drive to ross-on-wye the weekend and my mpg dropped....only .1 but it did drop,factor maybe?

 

[Yellow Dave]

the 2nd down stream lambda sensor is the one that actually alters the fuelling and identifies if the CAT is not working efficiently so I'd be looking at that 1st

 

[bengtt5]

the 2nd down stream lambda sensor is the one that actually alters the fuelling and identifies if the CAT is not working efficiently so I'd be looking at that 1st

dont you mean the second one checks the cat is working and the first alters the fueling