Passat B8 140tdi DPF help

[Cutch42]

Hi all,

Ive got a late 2018 Passat Alltrack wolfy 140tdi (engine code DFHA) that's done just over 120k kms and long story short I've been told the DPF has failed and requires replacement.

Pricing for a new DPF unit alone from VW is $6k which is untenable so I'm going to give it a crack myself by getting a second hand dpf from a wrecker, I'm just after some help regarding part numbers.

The DPF currently on my car from factory is 04L131673B and VW have told me the replacement part number is 04L131678RX - they said either of those part numbers will fit. My question is does anyone out there know if there are other compatible part numbers? For example I've found one with part number 04L131602N that's off an earlier 2018 tiguan with the same engine code but it's an absolute rabbit hole trying to figure out what superseded/updated part numbers would be compatible.

This is one of my first posts so apologies if I've made any errors but I would seriously appreciate it if anyone in the community could shed some light on this if they know!

Cheers
James

[Guest001]

Suffix letters are usually just newer versions of same thing

[Flipper Dog]

ETKA is listing 04L131678RX as a match for your engine along with 04L131678QX.
04L131673B was dropped for 04L131673BX which was replaced by 04L131678KX and then 04L131678RX.
Not sure if the Tiguan's 04L131602N would fit but this is replaced by 04L131671NX now.

DFHA was used in the following vehicles:
Arteon 2017 - 2020
Passat 2017 - 2024
Tiguan 2016 - 2020
Tiguan allspace 2017 - 2021
Audi Q2 2016 - 2018
Audi Q3 2018 - current
Skoda Karoq 2018 - 2020
Skoda Kodiaq 2016 - current
Skoda Superb 2015 - current

[MIG]

The X in the part number denotes that it's an exchange part, so if doing it via VW, the old DPF needs to be returned as a core.
If shopping around at wreckers the part number won't have the X on it.

[Lucas_R]

Its very very unlikely that your DPF has failed. Extremely unlikely. If you have taken your car to a VW dealership for diagnosis then they will simply say you need to replace the DPF because they will not repair or recondition parts.

What has apparently failed on your DPF? Is the honeycomb structure damaged (eg cracked or melted etc). Is it blocked from ash or soot buildup?

The DPF is almost always the result of something else on the engine being the issue and the DPF cops the punishment and gets clogged. THE DPF is the "last link in the chain" so to speak, so something upstream nearly always is causing a problem, and the DPF is the first thing to show a symptom when it gets clogged.

1) Make sure whatever the root cause of the issue has been fixed (eg leaking injectors/boost leak/failed DPF pressure sensor etc). This is a very important step, and if skipped or not done correctly, your new/reconditioned DPF will fail prematurely as well.
2) Unless your DPF has sustained a lot of damage, the DPF can be removed from the car and professionally cleaned/restored to almost new condition for a fraction of what you have been quoted.

Do a Google search for DPF cleaning Melbourne and you will find shops that specialist in DPF cleaning/reconditioning.

Bear in mind that you will still need to pay for a mechanic to remove/replace the DPF which on a transverse 2.0TDI is not an easy task - so expect probably 6-8 hours of labour charge just for the removal/replace.

As an alternative, if you do need to replace the DPF due to irreversable damage, this European website has multiple in stock to suit the DFHA engine code. Exhaust particle filter for Volkswagen Passat [2015-] - Car partsUsed parts online

[Cutch42]

I really appreciate all your responses so far - thanks.

ETKA is listing 04L131678RX as a match for your engine along with 04L131678QX.
04L131673B was dropped for 04L131673BX which was replaced by 04L131678KX and then 04L131678RX.
Not sure if the Tiguan's 04L131602N would fit but this is replaced by 04L131671NX now.

DFHA was used in the following vehicles:
Arteon 2017 - 2020
Passat 2017 - 2024
Tiguan 2016 - 2020
Tiguan allspace 2017 - 2021
Audi Q2 2016 - 2018
Audi Q3 2018 - current
Skoda Karoq 2018 - 2020
Skoda Kodiaq 2016 - current
Skoda Superb 2015 - current

Really helpful info there flipper thank you. I'd got as far as determing 04L131678RX was the current part match but didn't know about those older ones so will be helpful in my search. I've reached out to VW to see if they know if the tiguan part will fit but don't have high hopes they will even know

The X in the part number denotes that it's an exchange part, so if doing it via VW, the old DPF needs to be returned as a core.
If shopping around at wreckers the part number won't have the X on it.

Thanks MIG yes I just found out that the other day

Its very very unlikely that your DPF has failed. Extremely unlikely. If you have taken your car to a VW dealership for diagnosis then they will simply say you need to replace the DPF because they will not repair or recondition parts.

What has apparently failed on your DPF? Is the honeycomb structure damaged (eg cracked or melted etc). Is it blocked from ash or soot buildup?

The DPF is almost always the result of something else on the engine being the issue and the DPF cops the punishment and gets clogged. THE DPF is the "last link in the chain" so to speak, so something upstream nearly always is causing a problem, and the DPF is the first thing to show a symptom when it gets clogged.

1) Make sure whatever the root cause of the issue has been fixed (eg leaking injectors/boost leak/failed DPF pressure sensor etc). This is a very important step, and if skipped or not done correctly, your new/reconditioned DPF will fail prematurely as well.
2) Unless your DPF has sustained a lot of damage, the DPF can be removed from the car and professionally cleaned/restored to almost new condition for a fraction of what you have been quoted.

Do a Google search for DPF cleaning Melbourne and you will find shops that specialist in DPF cleaning/reconditioning.

Bear in mind that you will still need to pay for a mechanic to remove/replace the DPF which on a transverse 2.0TDI is not an easy task - so expect probably 6-8 hours of labour charge just for the removal/replace.

As an alternative, if you do need to replace the DPF due to irreversable damage, this European website has multiple in stock to suit the DFHA engine code. Exhaust particle filter for Volkswagen Passat [2015-] - Car partsUsed parts online

Really awesome points you've made Lucas thank you. So one day driving along and I go to accelerate and the revs would go all jerky like it was trying to find a gear (that's what it felt like to me) - revs would go up and down up and down and the car would jerk and then it stalled. No immediate CELs or anything. I restarted the car and same issue, but eventually EPC light on and car into limp mode and I could get it home. Scanned via VCDS and found P0401 EGR system insufficient flow and P0402 EGR excessive flow codes. The next day I drove the car and it was fine, no issues but booked it in to a local reputable euro garage as car is out of warranty so didn't go to VW (maybe an error I'm not sure). They sent me through quite a detailed report of which I'll include in the next post but essentially said the DPF is failing (didn't specify how) and it's clogging the low pressure EGR system. They said they've seen this only on one other car (audi with similar engine).

I'm pretty handy, have taken out gearboxes and subframes etc before so while it looks like a massive PITA job I reckon I can handle it.

Would there be a way for me to determine via VCDS or otherwise if something upstream has caused this issue?

Cheers
James

[Cutch42]

Report from garage:

"Carried out fault scan and found faults logged for " Exhaust Gas Recirculation Insufficient & Excessive Flow Detected " Cleared faults and carried out road test and was unable to replicate the customers driveability concerns. Checked electrical and mechanical operation of both EGR valves. Confirm integrity of sensors related to the EGR operation ( Differential Pressure Sensor, Air Flow Meter, Exhaust Temperature, Manifold Pressure ). During road test monitored exhaust gas pressures, found soot level in exhaust to be reading 0 grams ( Suspect fault appeared for customer during diesel particulate filter passive regeneration ) Carried out guided test plan for EGR operation VIA Volkswagen diagnostic system ( ODIS ), at time of test both high and low pressure EGRs operated within specification and flowed the correct air mass. Removed airbox, boost pipe and turbo mouth to gain visual access to low pressure EGR system. Removed and inspected output pipe from low pressure EGR and found a build up of soot in pipe and on control flap for the low pressure EGR. During the low pressure EGR being located AFTER the diesel particulate filter, there should be no carbon deposits ( Soot ) in the low pressure EGR system. This is an indication that the diesel particulate filter is failing and exhaust gasses are passing through unfiltered which correlates with the low exhaust gas measurements, and are now clogging the low pressure EGR system. Checked exhaust tail pipe and found traces of soot in the exhaust tips. Referred to available technical studies which are attached with photos, these confirm our findings that the diesel particulate filter is failing and has caused damage to the low pressure EGR system. To ensure a complete repair, replacement of the exhaust emission module ( Diesel particulate Filter & AdBlue Catalyst Unit, Low Pressure EGR Collector) as well as the low pressure EGR assembly will be required. The fault appears to be in the early stages and it is unknown how long until reoccurrence or worsening of symptoms appear."

[benough]

If the DPF was cactus, you would know before it backed up into the EGR.

I don't have enough knowledge and experience DPFs directly, but I have experience with EGR in VW and other Diesels, and it always goes first.

My suggestion is to take the EGR out and cleaned/diagnosed first. Also, it will be significantly cheaper than a new DPF.

What kind of driving do you do? i.e. do you get it up to temp on longer drivers rather than short ones? My DPF is at 315,000km b/c I flog the car at every oppurtunity.

[Cutch42]

If the DPF was cactus, you would know before it backed up into the EGR.

I don't have enough knowledge and experience DPFs directly, but I have experience with EGR in VW and other Diesels, and it always goes first.

My suggestion is to take the EGR out and cleaned/diagnosed first. Also, it will be significantly cheaper than a new DPF.

What kind of driving do you do? i.e. do you get it up to temp on longer drivers rather than short ones? My DPF is at 315,000km b/c I flog the car at every oppurtunity.

Thanks Benough. Yeah my original thoughts were to take both the DPF and EGR components off and get them cleaned, especially cos I wasn't getting specific DPF codes only the EGR codes I mentioned above. Only issue is if that doesn't work then I'll have to do the whole job again and can't really afford to have the car off the road long as I need it for work.

My driving is about 50/50 short (<20km) and long (>50km) trips so it definitely gets up to temp regularly

[h100vw]

You could have the DPF cleaned out and perform static regen. Liqui moly produce products I have used for this that worked. The fluids cost you but there's not much getting your hands dirty. Pro-Line Diesel Particulate Filter Cleaner | LIQUI MOLY

[Cutch42]

After doing a bit more research and guided by your answers I decided against replacing the DPF for now and instead doing a full clean out of that and the EGR module.


I downloaded VAG DPF (fantastic app!) and it showed ash levels at 40g (~50%) and differential pressure around 12-17hpa at idle, so a little high but not too bad



For the DPF clean (oreilys autos on youtube has heaps of vids on this) I used JLM's DPF cleaner and flush kit with a fluid transfer pump into the DPF pressure sensor hose (they make a gun style tool specifically for this but the fluid pumped worked just fine)


First step was pumping in the cleaner, letting it sit for a few minutes, then running the engine at 1.5k rpm for 5 mins. I unplugged the MAF sensor before starting to ensure the EGR valve stayed closed. Half the flushing fluid was then pumped in with the engine running and revs up, given time to clear out and then repeated with the other half. Momentarily I had the world's most expensive bubble machine


After letting it clear out for a bit longer I took it for a test drive and instantly the car felt more responsive. After resetting the ash level via VCDS I took it for a longer drive until a regen was completed and now the differential pressure as around 4hpa at idle - seems to have worked pretty well I think


The next step was to take the EGR cooler off and give that a clean as the original fault codes were relating to EGR flow. This was a prick of a job due to access, so first I removed the air intake components, charge pipe, battery and moved some other lines out of the way to clear space up top


Most of the job was then done from underneath - removed the undertray and front section of the exhaust so I could start pulling hoses off the EGR from below. Basically every hose had welded itself on to its pipe due to all the heat back there so a selection of picks, patience, swearing and a heat gun were needed. I didn't take any photos from underneath because I wasn't planning on this post at the time so apologies. Finally I could snake out the EGR from up top and it had definitely collected some soot


So I gave that a good clean, got everything back together and the car is running great - fingers crossed it stays that way.

Thanks again for your help guys and hopefully I've avoided paying the $9k originally quoted... all up this job cost me about $500 (DPF cleaner, remote hose clamp tool (essential), new seals/gaskets/clamps from VW) so at minimum buys me some time but pretty happy with how it all went

[Lucas_R]

Great result - funny you mention O'Reilly autos on Youtube as I watch his videos too. I went looking on his channel the other day to see if I could find a similar issue to yours but couldnt find one.

[Cutch42]

Great result - funny you mention O'Reilly autos on Youtube as I watch his videos too. I went looking on his channel the other day to see if I could find a similar issue to yours but couldnt find one.

Yeah he's great, no nonsense and knows his **** when it comes to DPFs. I found one he did on a skoda octavia with a similar enough engine to mine (both EA288's) so that helped heaps

[benough]

Mad respect!