P0421 & P0431 for years...
#1
P0421 & P0431 for years...
Hello,
I have a 2003 A4 Q 3.0 that has been throwing these two "Catalytic converter" codes for YEARS. They started well before the odo hit 100k and now that it has 144k, I'm trying to see if it's worth fixing.
Because I'm getting BOTH codes, is that indicative that one or both converters is shot or could it be an O2 sensor?
Any advice is appreciated!
\\Brew
I have a 2003 A4 Q 3.0 that has been throwing these two "Catalytic converter" codes for YEARS. They started well before the odo hit 100k and now that it has 144k, I'm trying to see if it's worth fixing.
Because I'm getting BOTH codes, is that indicative that one or both converters is shot or could it be an O2 sensor?
Any advice is appreciated!
\\Brew
#3
I would like to know what this means: upgrade to hfc with a spacer??
Got any DIY type links for me please?
//Brew
#4
Hello,
I have a 2003 A4 Q 3.0 that has been throwing these two "Catalytic converter" codes for YEARS. They started well before the odo hit 100k and now that it has 144k, I'm trying to see if it's worth fixing.
Because I'm getting BOTH codes, is that indicative that one or both converters is shot or could it be an O2 sensor?
Any advice is appreciated!
\\Brew
I have a 2003 A4 Q 3.0 that has been throwing these two "Catalytic converter" codes for YEARS. They started well before the odo hit 100k and now that it has 144k, I'm trying to see if it's worth fixing.
Because I'm getting BOTH codes, is that indicative that one or both converters is shot or could it be an O2 sensor?
Any advice is appreciated!
\\Brew
I think because the CEL is on, I'm getting terrible gas mileage..
//Brew
#6
I'd first check your plugs to see if they're fouled and replace if they are. If plugs are badly fouled they won't spark properly giving an incomplete burn which leads to premature failure of o2 sensors and cat.
After plugs I'd replace the pre cat sensors and drive for a week and see if fuel economy improved then replace the cats and post cat sensors which would eliminate the engine light.
The reason for leaving the cat and post cat sensors for last are that they don't affect how the car runs. The post cat sensor checks that the cat is filtering properly and don't affect air/fuel ratio; the cat is just a filter protecting the birds and the bees.
After plugs I'd replace the pre cat sensors and drive for a week and see if fuel economy improved then replace the cats and post cat sensors which would eliminate the engine light.
The reason for leaving the cat and post cat sensors for last are that they don't affect how the car runs. The post cat sensor checks that the cat is filtering properly and don't affect air/fuel ratio; the cat is just a filter protecting the birds and the bees.
#7
I'd first check your plugs to see if they're fouled and replace if they are. If plugs are badly fouled they won't spark properly giving an incomplete burn which leads to premature failure of o2 sensors and cat.
After plugs I'd replace the pre cat sensors and drive for a week and see if fuel economy improved then replace the cats and post cat sensors which would eliminate the engine light.
The reason for leaving the cat and post cat sensors for last are that they don't affect how the car runs. The post cat sensor checks that the cat is filtering properly and don't affect air/fuel ratio; the cat is just a filter protecting the birds and the bees.
After plugs I'd replace the pre cat sensors and drive for a week and see if fuel economy improved then replace the cats and post cat sensors which would eliminate the engine light.
The reason for leaving the cat and post cat sensors for last are that they don't affect how the car runs. The post cat sensor checks that the cat is filtering properly and don't affect air/fuel ratio; the cat is just a filter protecting the birds and the bees.
Those sensors are responsible for telling the ecm how well the cats are working , thus responsible for the fault codes that are present.
#10
Edit: yeah I was wrong, my logic made sense at the time. Replacing all 4 o2 sensors and cats will rid the fault and should return both power and fuel economy.
Last edited by jtblue; 11-19-2013 at 06:58 PM.