Catalyst System Efficiency Below Threshold (Bank 1)

[curlykevs]

i have removed my cat and ran a thriugh pipe but mil light slill on with 0420 catalyst system efficiency below threshold (bank 1) why i tam i getting this code when dont have a cat thanks x reg 1.6

[mintalkin]

the cat will have pre and post lambarda sensors to measure that the cat is doing its job,with the cat removed the sensors detect this hence the code,also removing the cat is now an MOT fail.

[curlykevs]

thanks i thought getting rid of cat would get rid of code new cat it is then

[artscot79]

sadly it doesnt work that way however it can be any one of the sensors also thats faulty or both and not the cat