#1: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 4:44 am ---- i have pluged my car in to a diagnostic plug and p0420 came up. Catalyst System Efficiency Below Threshold (Bank 1). i no my car had a new cat back in january. so could it be a possible lamda sensor problem?
#2: Re: p0420 fault code. Author: Big_Rich180, Posted: Thu Sep 15, 2011 4:47 am ---- Lamba sensor would be my guess.
#3: Re: p0420 fault code. Author: MrBSI, Location: What's it to you? ? ?Posted: Thu Sep 15, 2011 4:50 am ---- Is this a new or stored fault code?
Diagnosed correctly when the cat was replaced or was it just the normal parts thrown at it till its fixed routine?
Genuine cat fitted?
#4: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 4:50 am ---- which 1? top or bottom sensor
#5: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 4:54 am ---- the cat was replaced back in january before i purchased the car. the engine managment light came on sunday just gone so new. unsure if the cat is genuine.
#6: Re: p0420 fault code. Author: Deckchair5, Location: Bath UKPosted: Thu Sep 15, 2011 5:09 am ---- P0420 means ECU has spotted that the post cat O2 sensor signal is following too closely the signal from the pre cat O2 sensor so logically it believes the cat isn't doing very much so it fires up a cat efficiency warning. It doesn't mean there is anything wrong with O2 sensors
At steady rpm the pre cat signal should be oscillating and post cat fairly steady so looking at the graph output of both of them would be the first step Last edited by Deckchair5 on Thu Sep 15, 2011 5:18 am; edited 1 time in total
#7: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 5:10 am ---- ok i will give that ago. is there any bits of software you would recommend? i have a usb obd11 reader
#8: Re: p0420 fault code. Author: Deckchair5, Location: Bath UKPosted: Thu Sep 15, 2011 5:20 am ---- If your car is EOBD then there's a bucket load of software available. Ideally you want something with a graphical output so you can compare the two, you can still see what's going on though with the raw figures
#9: Re: p0420 fault code. Author: MrBSI, Location: What's it to you? ? ?Posted: Thu Sep 15, 2011 5:48 am ---- Whats the betting its a cheap / s**te non genuine cat thats been fitted
#10: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 5:56 am ---- just going through the paper work and the cat was £230 . so not that cheap and ive been using easy obd2 software but it keeps coming back with vehicle trouble code not available
#11: Re: p0420 fault code. Author: gazza82, Location: South BucksPosted: Thu Sep 15, 2011 6:05 am ---- What is the year of your car? Petrol post sept 2001?
#12: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 7:33 am ---- petrol 1.1 2003
#13: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Thu Sep 15, 2011 7:33 am ---- petrol 1.1 2003
#14: Re: p0420 fault code. Author: Deckchair5, Location: Bath UKPosted: Thu Sep 15, 2011 7:59 am ---- That'll be EOBD2 then so you're fine
Here's Gendan software and some good looking O2 sensors on tickover
but if the bottom trace was similar to the top one then that shows the cat isn't doing its stuff
#15: Re: p0420 fault code. Author: dumdum0910, Location: letchworthPosted: Sun Oct 16, 2011 11:59 am ---- thought i would bring back up n old topic. this code came up today have worked out its every 3 weeks it seems 2 pop up . ive changed the panel filter back to standard n replaced the ngk plugs for bosch super 4s to see what happens.
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and ive been using easy obd2 software but it keeps coming back with vehicle trouble code not available
have worked out its every 3 weeks it seems 2 pop up . ive changed the panel filter back to standard n replaced the ngk plugs for bosch super 4s to see what happens.
