[Whysitcold]

Hey guys, just installed an AA catted downpipe on my 21 M440ix and drove it for around 200 miles before I had a CEL appear. Pretty disappointed with that, but I checked the code and I’m showing P0420. Downpipe was purchased used so it’s gone through its break in period and I had a new gasket put on during it’s install.

Can anyone throw a suggestion as to why it’s coming on? Car is driving fine but it’s annoying that I spent the extra money to avoid the CEL in the first place

[GA/\/\/\/\A_CT]

2 things I would recommend

1) carefully go over the install and make sure there are no leaks at the coupling locations

2) if you floored the accelerator before the cats warmed up; try warming up first.

The CEL will go away if it’s something like you did #2 once….

Otherwise, see if AA can advise you.

I’ve had 2 separate units in 2 separate cars and only had the #2 issue once on a very cold day.

[Whysitcold]

Originally Posted by GA/\/\/\/\A_CT

2 things I would recommend

1) carefully go over the install and make sure there are no leaks at the coupling locations

2) if you floored the accelerator before the cats warmed up; try warming up first.

The CEL will go away if it’s something like you did #2 once….

Otherwise, see if AA can advise you.

I’ve had 2 separate units in 2 separate cars and only had the #2 issue once on a very cold day.

Thanks for the recommendations. I checked all the fittings and didn’t find anything loose, went ahead and cleared the code. Let’s hope it doesn’t come back. I’ll contact AA if it does

[1QuikWS6]

I have 2 AA catted DP on my BMWs. 435 and M440. Never a CEl and no issues. Passes insp here in PA every yr.

AA has a great warranty and guaranteed no CEL, but doubt they will be any help since you bought the DP used 2nd hand...

[peelerec]

Originally Posted by Whysitcold

Hey guys, just installed an AA catted downpipe on my 21 M440ix and drove it for around 200 miles before I had a CEL appear. Pretty disappointed with that, but I checked the code and I’m showing P0420. Downpipe was purchased used so it’s gone through its break in period and I had a new gasket put on during it’s install.

Can anyone throw a suggestion as to why it’s coming on? Car is driving fine but it’s annoying that I spent the extra money to avoid the CEL in the first place

Firstly, are you sure it is a authentic AA catted dp? Secondly, don’t be disappointed if purchasing secondhand. You have no idea the condition or circumstances it was used before you acquired. What if the filter is damaged due to user error?
As others have suggested, I would also contact AA for any suggestions they may have.

[prostcfc]

Just checked AA's website, and warranty doesn't transfer owners. Here's what warranty covers for new DPs:

"Covered by 5 Year / 50,000 Mile Warranty (on shell and tube ends) and 2 year / 25,000 Mile Warranty on the Catalytic core"

[mike@x-ph.com]

You should never buy a used active downpipe.

1- you lose the warranty which is the most important part of this downpipe with the CEL

2- you don't know if the downpipe is good. Let me explain.
if a customer gets the active autowerke and it triggers the check engine light, they file a warranty with us or active, and we send them a new downpipe. he might have sold you his original downpipe knowing fully well its defective.

[Whysitcold]

Thanks for the replies guys. Learned my lesson on his one! Light hasn’t returned so I’m hoping it stays that way and was merely caused by me not letting the cat heat up.

[mondayze]

Originally Posted by mike@x-ph.com

You should never buy a used active downpipe.

1- you lose the warranty which is the most important part of this downpipe with the CEL

2- you don't know if the downpipe is good. Let me explain.
if a customer gets the active autowerke and it triggers the check engine light, they file a warranty with us or active, and we send them a new downpipe. he might have sold you his original downpipe knowing fully well its defective.

they get to keep the first downpipe? thats kinda weird, couldnt they fake a CEL?

[Seba77W]

Originally Posted by Whysitcold

Thanks for the replies guys. Learned my lesson on his one! Light hasn’t returned so I’m hoping it stays that way and was merely caused by me not letting the cat heat up.

Sounds good keep us posted if it comes back.

[G22Junkie]

I’ve heard on the AA catted DP that your car can throw a CEL in the first few hundred miles as your car adapts. Your car needs to learn and adapt to the new stuff and I guess there’s a small break in period for that. In the instances I’ve heard about, once you clear the code after then first time it won’t come back. This is the info they were given directly from AA for example if you bought new from them they will tell you this is common and to clear the code and should be good. Then if it still comes back they will exchange it. This is all info I heard from others not something I have dealt with personally so can’t say for sure it’s 100 percent accurate but have heard the same from multiple people so pretty confident it’s accurate. Wait it out, drive her hard and if it comes back I would still give active a call and see what they say. While you might not have the warranty I’m sure they will still be happy to give some suggestions to help.

[mike@x-ph.com]

Originally Posted by G22Junkie

I’ve heard on the AA catted DP that your car can throw a CEL in the first few hundred miles as your car adapts. Your car needs to learn and adapt to the new stuff and I guess there’s a small break in period for that. In the instances I’ve heard about, once you clear the code after then first time it won’t come back. This is the info they were given directly from AA for example if you bought new from them they will tell you this is common and to clear the code and should be good. Then if it still comes back they will exchange it. This is all info I heard from others not something I have dealt with personally so can’t say for sure it’s 100 percent accurate but have heard the same from multiple people so pretty confident it’s accurate. Wait it out, drive her hard and if it comes back I would still give active a call and see what they say. While you might not have the warranty I’m sure they will still be happy to give some suggestions to help.

you are correct that the downpipe will trigger the check engine light during the first 100 miles. but he bought it used, so it has already gone through that cycle.

[G22Junkie]

[QUOTE="mike@x-ph.com;30931418"]you are correct that the downpipe will trigger the check engine light during the first 100 miles. but he bought it used, so it has already gone through that cycle.

Ahhh gotcha…. Appreciate ya. I always thought it was the car itself that had to learn and adapt due to the different air/fuel ratios. The way I was explained was that it’s the computer in the car not the actual downpipe itself that had the break in period. Again, not my field of expertise as I’m just going on what others have told me… good luck to OP I hope CEL stays OFF for him!