[kbturbo]

After owning 3 tdi jettas, I picked up a 10 335d and love the car. Currently has 50k on the clock and while on my way to work (I own a repair/dyno tuning facility) the ses light came on. I pulled the code and it was p0401 egr insufficient flow detected. Since it still has the cpo warranty, I made an appt to take it in on Wednesday. My question is, how far can I expect them to dig into the car to remedy carbon buildup under warranty. What should I be asking them to inspect/clean/repair when it's there? Thanks for any input

[335ddd]

as a side question where in PA are you? I have JBD and wanted to dyno HP increases from stock to 100% if that is something your shop does.

also there is a SIB 11 03 14 which can help you with CBU questions.

[kbturbo]

I just saw that tsb. Thanks for the heads up

My shop is 30 miles north of Harrisburg off I81. We would absolutely be willing to do something like that (then I could go for a ride in yours to see what the jbd is like lol)

[335ddd]

Originally Posted by kbturbo

I just saw that tsb. Thanks for the heads up

My shop is 30 miles north of Harrisburg off I81. We would absolutely be willing to do something like that (then I could go for a ride in yours to see what the jbd is like lol)

i think mine has CBU as well. hopefully i get it cleaned as well in a near future.
then i will most likely sell JBD and get a tune.

meanwhile i would like to get idea how much HP i have now so later after the cleaning i can compare the #s.

Better yet i have JBD out so you can test it on your car as well.

[kbturbo]

I would definitely be interested in buying your jbd because my car is still under warranty. You could sell it to me and we could trade delivery for dyno pulls lol

[kbturbo]

Just a little update: the service manager from the dealership called me. They said I didn't have too big of a cbu issue but they are putting a new intake plenum on due to the flaps needing replaced and they aren't available separately. They are also putting a new maf sensor on. They didn't think they would be replacing the egr valve which kind of surprised me. Thoughts?

[kbturbo]

Picking the car up tomorrow. They only put a mass air flow sensor on. Sa said that once they put the maf on, the flaps in the old intake worked. They also kept the old egr valve on. Does this seem like the right fix to that dtc?

[Mik325tds]

That does sound a little bit fishy. Replacing the MAF sensor to fix the EGR incufficient flow I can live with, because the DDE expects less air through the filter (and MAF) when opening the EGR and a defective MAF could cause the DTC to be set. Also, not replacing the EGR valve is fine because that can be cleaned fairly easily.
But the story about the swirl flaps needing replacement and then all of a sudden start working with a new MAF sensor somehow doesn't work for me.
However, being under CPO I wouldn't worry too much if I were you. If you do have a swirl flap issue or excessive CBU other codes will come up and they'll have then to clean it.
Just replacing the intake plenum I'd call a half ass job, though.

[ingenieur]

Originally Posted by kbturbo

Picking the car up tomorrow. They only put a mass air flow sensor on. Sa said that once they put the maf on, the flaps in the old intake worked. They also kept the old egr valve on. Does this seem like the right fix to that dtc?

The HFM is how EGR flow rates are monitored.

[kbturbo]

Ok, thanks guys. Another year left on the cpo warranty so we will see what happens

[iaknown]

Yea, see how it plays out. From a business standpoint it doesn't make sense for them to replace multiple parts on it if they feel just one may fix it. But good thing is you have the warranty so you will know soon enough and be covered if it isn't right.

[mefferso]

I have the same P0401 error code but haven't notice any obvious adverse effects on the engine running wise. So I've been sitting on it, thinking that it is really CBU, I'd like to wait to get that fixed at the end of my CPO warranty.