having these new codes coming up p0420 and p0430 saying catalyst below efficency on bank 1 and bank 2 . but cant see how both could go at the same time any ideas
codes p0420 and p0430 on my a4 2.4 v6
- Thread starter scanny1
- Start date
id do some close looking at the pre and post lambda sensor signals on both banks if i were you.
check supply/signal voltages etc. create an air leak on the inlet somewhere. see if the signal voltages change?
check supply/signal voltages etc. create an air leak on the inlet somewhere. see if the signal voltages change?
how do you check the pre and post lambda sensor do i need live data or some sort to do that
has it just got 4 wire lambda sensors both pre and post?
if it has, as a basic guide.... if you look at the live data at the signal voltages both pre and post. the pre sensor should be switching between .2v and .8v....... if the cats healthy the post lambda voltage signal should be pretty steady (.4-.6v). if thats switching up and down too, as much as the pre sensor is, then it suggests the cat isnt working as well as it should be. as the post lambda is having to further correct the mixture to keep the emissions down trying to make up for the cat being inefficient.
if the car has 6 wire (broadband/wideband) pre sensors then they are more complicated and really you need them testing with a scope or diagnostically with the vas5052 or similar (a sensor ageing test its called).
if it has, as a basic guide.... if you look at the live data at the signal voltages both pre and post. the pre sensor should be switching between .2v and .8v....... if the cats healthy the post lambda voltage signal should be pretty steady (.4-.6v). if thats switching up and down too, as much as the pre sensor is, then it suggests the cat isnt working as well as it should be. as the post lambda is having to further correct the mixture to keep the emissions down trying to make up for the cat being inefficient.
if the car has 6 wire (broadband/wideband) pre sensors then they are more complicated and really you need them testing with a scope or diagnostically with the vas5052 or similar (a sensor ageing test its called).
