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Old 07-29-2018, 11:48 PM
disillusioned disillusioned is offline
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Location: Tempe, Arizona
Join Date: Jan 2011
Posts: 15
Mein Auto: 2007 335i
DPF "needs replaced"... for $5,900... at 65k miles

Hi all! I've been digging into various DPF threads here, and collecting from the mash of info, and just wanted to see if I'm missing anything before going into the weeds here.

My wife's car (which was recently driven over 100 miles at constant highway speed) has thrown a number of diesel/emissions system errors while it was still during mfg warranty and then CPO warranty, usually related to the DEF system, but I don't have the paperwork in front of me. This includes one final time a month before the CPO warranty ended, in which I made them swear up and down that the emissions system wasn't going to come back to bite me.

Imagine my surprise when my wife gets an "incorrect exhaust fluid" error... on a car we've never (personally) touched the exhaust fluid on. (We've always had the dealer do oil changes, including the most recent one in April.)

The dealer tells me they're having some trouble diagnosing, then gets back to me and explains that it appears to be a "bad diesel particulate filter" and that it will need to be replaced, for $5,900. I tell him to sharpen his pencil and figure out a way to make that number NOT that number, because I was assured that we had gotten all the emissions issues out of the woodwork.

I'm waiting to hear back on that, but obviously I'm expecting them to tell me to go pound sand. This dealership, as a general rule, gives zero ****s. (The only reason I took it here was because of the trail of previous DEF issues, and seeing if I could lever that into a goodwill fix from them.)

The specific notes on the estimate state "found DPF clogged, performed regen, still clogged", but the advisor had made it sound like a) they weren't able to get it to perform the regen, and b) they're sure it's not the NOX or thermostat... which sounds like bull**** to me.

My questions:

1) I feel like replacing the DPF should be the very very last action we take, right?
2) Why would a "clogged" DPF throw a "wrong exhaust fluid" message instead of what appears to be the typical case of something specific to the DPF or limp-home mode?
3) I had a local shop quote me $1,500 to clean the DPF... should I start with a cleaning fluid first? Or trying to trigger a regen myself from Carly?
4) It sounds like I need to truly diagnose that the NOX and thermos aren't actually bad... the dealer maintains that they don't think they are, but I have no idea how they tested them, or if they really did.
5) Can I clear or reset the 200 mile warning with Carly or something similar? At least while I figure out a plan of action?

My plan of action:
1) Get the dealer to give me the error codes they're seeing, and the telemetry on backpressures and ash levels on the DPF, as well as last regen times
2) Get the dealer to confirm as best they can that NOX sensors and thermo are still good. Push for a NOX sensor fix anyway, since that's now under extended LW
3) See if they can clear the code/extend the time for now, while I figure things out
4) If they won't fix, try Carly manual regen, Carly manual exhaust temp diagnosis
5) If that doesn't work... try a DPF cleaner fluid?
6) If all that fails, have the local shop do the actual cleaning?
7) Curse myself for not living in California, since DPF is covered by a separate extended warranty there for 7 years

Any additional insight would be greatly appreciated, or if I'm missing something obvious, or any other questions to push on the dealer.


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