DPF Pressure Sensors Melted

Dhillbarn

New member
Joined
Jan 4, 2022
Location
Kentucky
TDI
Facelift
Had the same thing happen. I'm assuming one of the sensors broke while doing the timing belt job allowing hot gasses during Regen and melting every thing. Found 2 new sensors and two pigtails on Amazon for roughly 90$ problem fixed.
 

blakjak

Member
Joined
Jul 22, 2012
Location
Missouri
TDI
2015 Passat TDi SEL Prem, 2014 Jetta TDi, 2011 Golf TDi
Chalk up another melted sensor after a TB change. 2015 Passat CVCA - 126k miles. Maybe 60-80 miles after changing the belt, check engine light came on. P2456 code. Cleared it, drove it again the next day and it came back on after about 30 miles.

Opened up the pouch this evening and found it melted and sooty. Expect it'll be replaced under the extended emissions warranty. I did move the pouch and hard lines while doing the TB service. Not much, but apparently enough to do something.
 

dataiv

Veteran Member
Joined
Feb 12, 2005
Location
Ottawa, ON
TDI
2015 Golf Wagon TDI 6MT
CRUA TB job a couple weeks ago and no melting, but it sounds like it is different than CVCA in layout. I did have to move and disconnect the hard lines in front of the upper TB cover, but did not have to touch the pouch or move those lines much out of the way. At 1000km since and 2 or 3 regens, no problems.
 

dataiv

Veteran Member
Joined
Feb 12, 2005
Location
Ottawa, ON
TDI
2015 Golf Wagon TDI 6MT
Agreed, not a coincidence based on my looking at it while doing my TB change. Easy to knock them a bit too much. In CRUA it was easy to avoid, luckily!
 

r90sKirk

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Joined
Oct 21, 2003
Location
CedarTuckey, Michigan
TDI
All TDI's - No gassers! Luxo-Tourer = 13 Passat (hands down, the nicest car we've ever owned), Most fun = MK4 Golf
Mine also melted shortly after a TB service that I did. It must not take much movement, as those hard lines were not moved that much. Just enough to get the upper TB cover off, and I typically pry/slide the plastic bracket which holds the hard lines in lace to the upper TB cover away first. I don't remove the DEF injector either, only remove the two coolant lines from the injector, and swing those out of the way.
 

Mrrogers1

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Joined
Jun 25, 2006
Location
Omaha NEEEBRASKA
TDI
2011 Golf TDI 6MT, 2011 Jetta TDI DSG, 2015 Golf Sportwagen S TDI DSG
Dang, I helped buddy with tb change maybe a year back, it was pretty sweltering heat and he had this happen the very next day after doing the job. Had no clue what had happened so got a pair of sensors from Amazon and replaced. So crazy but glad to know it wasn't some freak event, even though he paid to replace them.
 

transam7801

New member
Joined
Aug 13, 2022
Location
Kentucky
TDI
2015 Passat TDI SE M6
I'd like to add another data point for this thread.

I just helped a buddy to his timing belt on his 2015 Passat TDI. Shortly after the job, he started getting codes and the car went into limp mode. Upon investigation, he found that the DEF injector was loose after the timing belt job. After tightening the clamp for the DEF injector, he had more codes and issues a few days later. This was when he discovered the differential pressure sensor burned up as others here have mentioned.

We did the timing belt job on my 2015 Passat TDI today, and I wanted to be sure I avoided the same fate. Before doing the timing belt job, I opened the heat protection pouch around the differential pressure sensors (use a screwdriver or else you'll rip it... trust me!). Midway through the job, I inspected the differential pressure sensor and noticed that the sensor on the left had the barb broken off in the hose.

I have two theories as to what happened to my buddies car and/or what's happening here:

Theory 1 (what I think is most likely) - The differential pressure sensor is being damaged during the timing belt change

This is mostly based on the experience mentioned above. I did not feel as if I had gotten rough with the sensor lines while doing the timing belt change, but I still had a failure. When I tried to extract the broken plastic from the rubber hose, it was extremely brittle and came out in small pieces. With this theory, the plastic of the sensor gets damaged during the timing belt change, but goes unnoticed since there are no errors associated with this failure mode (my friend drove his car with the burned up sensors for at least a few days without realizing it). The cracked sensor body allows exhaust gas to fill the protective pouch and instead turns the whole area into a mini oven, cooking the plastic off the sensors. If this were to be true, then it would probably be prudent to change these sensors while doing the timing belt.


Theory 2 - The loose DPF Injector clamp contributed to the failure

My buddy found this failure on his car before the burned up differential pressure sensors. In this theory, the leaky exhaust connection heated up the pipes that lead to the differential pressure sensors and contributed and/or caused the failure due to heat soak.



I posted some pictures to a blog for review along with the details above

 
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Midash2k

Member
Joined
Jul 12, 2018
Location
Oceanside, CA
TDI
2015 Jetta SEL TDI
Same story here. Took my 2015 EA288 Jetta in for timing belt change at 126K miles. CEL came on afterwards... after about 1 day for driving the sensors were melted.... appears the hoses were moved during the timing belt job and broke the plastic on the sensors.... VW covered under extended emission warranty. no problemo
 

Dhillbarn

New member
Joined
Jan 4, 2022
Location
Kentucky
TDI
Facelift
Just deleted and I must say the car runs way better. Also nice knowing some electronics that could fail are gone.
 

ticaf

Veteran Member
Joined
Nov 15, 2018
Location
US Mid-Atlantic
TDI
Stock 2015 Golf SW S Manual TDI
Just deleted and I must say the car runs way better. Also nice knowing some electronics that could fail are gone.
Cool. Would you mind telling the process you went through to delete.thanks

Also, is the car letting out smoke now?
 

Dhillbarn

New member
Joined
Jan 4, 2022
Location
Kentucky
TDI
Facelift
Cool. Would you mind telling the process you went through to delete.thanks

Also, is the car letting out smoke now?
I would do the timing belt job 10 times over before doing this but the results are worth it all. Removing the DPF/EGR was an absolute nightmare without a lift. 10/10 don't recommend doing without a lift but it can be done. I had roughly 8-10 hours in it. The biggest issues I encountered were coolant lines, house clamps were positioned towards the top when there is no access to them. I had to cut a couple off. I found a kit that is made by darkside but used the rawtech instructions. Delete kit was supplied by tditunes.com but do not recommend them not just because the lack of communication but because they marked the price up on the parts. Malone stage 2 tune. I plan on taking it to a local exhaust shop and getting them to do the bends and delete the factory muffler. 2015 CVCA.
 

okimavich

Veteran Member
Joined
May 20, 2004
Location
Maryland
TDI
`16 Audi A6
Anyone have the pin out for the plug on the passenger side? I need to rebuild it since it completely melted. I assume brown is pin2. Not sure which of the other two go to pins 1 and 3.
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
I'd hold off on doing a full muffler delete, straight pipe from turbo back with no resonator is going to be rather "aggressive", not sure if that's what you're looking for.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
There certainly seems to be a trend for this happening right after a timing belt change. I've so far only done a handful of CVCA t-belt jobs, but I've not had any come back with this issue. I take the whole pressure sensor assembly, with the hoses and pipes, and remove it all from the car, only disturbing the hoses where they go on to the LOWER pipes, down back near the lowest/rearmost spot. And for the DEF injector, I leave it be, I just remove the two coolant hoses from it and position that over to the front of the car.

Silly that VAG puts stuff like this in the way of the timing cover. They could have designed it better, although having just replaced a CVCA engine (M&P belt job by the owner... didn't go well), I can say that engine has a mind boggling overcomplicated cooling system. It is quite ridiculous actually.
 

Victor Huge

Veteran Member
Joined
Apr 18, 2009
Location
Alberta
TDI
Mk7 Golf TDI
Aaaah man, now I'm worried... I broke the nipple off the left most sensor and epoxied it back. Had no idea it was broken till re-assembly... For anyone doing this, I'd recommend removing the sensors with the line attached rather than trying to disconnect the lines...
 

pedroYUL

Veteran Member
Joined
Sep 8, 2011
Location
MI, USA
TDI
2015 Passat CVCA; 2015 GSW CRUA; 2012 wagon CJAA; 2004 wagon BEW
CVCA timing belt I had to get that stuff out of the way. CRUA I found a way to just work around it.

Nothing burned up. Phew!
 

okimavich

Veteran Member
Joined
May 20, 2004
Location
Maryland
TDI
`16 Audi A6
If I had known, I would have removed the sensor assembly.

However, considering how brittle the sensor had become from exposure to the high heat of the regen cycles, this is something that probably should be considered a periodic preventative maintenance item. It seems to be a matter of time before it disintegrates. TB change is a good time to do it since you're already there and moving/removing parts to make space. It's once every 130K miles.

Based on the pricing for the parts, VW seems to passively see it as a periodic maintenance part. A single sensor is $128.92. The entire assembly (2x sensors, bracket, 4x hoses, 2x metal pipes, clamps, clips and head shield) was $146.40. That's less than a $20 difference. Someone explain that one to me.

Plus, I would prefer to avoid having to rebuild the wiring because it all melted away or got damaged. Replacing the 2 connectors equates to 2x 3 pin connectors ($11.53 each) and 3x repair wires ($31.32 each). That's an extra $117.02 plus shipping and taxes I had to spend. Plus obligatory "shop supplies" (solder, shrink tube, tape, bandaids, neosporin, mumbled curses, etc).

Prices are from ID Parts.

Replacing the assembly on it's own wasn't too hard. It's just a little tight. Having long reach needle nose pliers, hose clamp pliers, hose pliers and a small ratchet w/ short T30 bit is helpful.
 

okimavich

Veteran Member
Joined
May 20, 2004
Location
Maryland
TDI
`16 Audi A6
Silly that VAG puts stuff like this in the way of the timing cover. They could have designed it better, although having just replaced a CVCA engine (M&P belt job by the owner... didn't go well), I can say that engine has a mind boggling overcomplicated cooling system. It is quite ridiculous actually.
My guess is that being on the outside of the TB cover provides the most convenient "coolest" location in the engine bay for those metal pipes. They created that routing with the intermediate metal hoses for a reason. I'm guessing it's to provide some amount of sinking for the exhaust heat before it hits the sensors. That all goes out the window if the sensor becomes an active escape path for the exhaust.

But I agree. It does seem overly complicated. Perhaps due in part to how they are bounded by manufacturing regulations from multiple jurisdictions.
 

Floader

Member
Joined
Oct 29, 2013
Location
Vermont
TDI
2014 Jetta DSG
This exact thing happed to me this weekend. Finished up the timing belt job and all was well, first regen its throwing the P2456 code. I never touched the stuff in the little pouch, just disconnected the lines down by the front of the cover, but I bet that was enough to break it. Guess its off the dealer and see if they will fix it under warranty. 2015 Jetta with 115K
 

cpinde

Active member
Joined
Sep 24, 2012
Location
Slower Lower Delaware
TDI
05 VW Passat, 04 Jetta, 06 BRM Jetta, sold 15 Golf current
This exact thing happed to me this weekend. Finished up the timing belt job and all was well, first regen its throwing the P2456 code. I never touched the stuff in the little pouch, just disconnected the lines down by the front of the cover, but I bet that was enough to break it. Guess its off the dealer and see if they will fix it under warranty. 2015 Jetta with 115K
Dealer will fix.
 

Victor Huge

Veteran Member
Joined
Apr 18, 2009
Location
Alberta
TDI
Mk7 Golf TDI
Even with the user being the cause? Dealer could argue that it's whoever did the timing belt's fault no?
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
they could try, but how would they know the TB was recently replaced?
 

Victor Huge

Veteran Member
Joined
Apr 18, 2009
Location
Alberta
TDI
Mk7 Golf TDI
Sooooo... I broke my left most sensor when I did the timing belt and epoxied it together, no issues thus far. I think what's happening is they get cracked during timing belt change and go unnoticed.

I'm curious, is the wiring to the sensor melting as well, when they fix it do they have to splice in wiring?

Oooooh I looked it up and the wiring is part of the ecu harness, don't let it melt!
 
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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
vw techs are good at making proper crimped splices in a pinch, i wouldn't worry much.

A crack in the sensor will allow EGT flow up and melt the wiring. The sensor is closed system to allow it to only measure pressure, not flow or temp.

my cjaa unit had a sensor fail but it was internal signal side, not a crack so no damage was done to wiring. Still have the failed unit in the garage.
 

jwood10

Member
Joined
Feb 18, 2022
Location
Ozarks
TDI
2015 Jetta TDI
Had the same thing happen. I'm assuming one of the sensors broke while doing the timing belt job allowing hot gasses during Regen and melting every thing. Found 2 new sensors and two pigtails on Amazon for roughly 90$ problem fixed.
I have this issue with the melted sensors and connectors. Could you provide the sensors and pigtails you got from Amazon? The local dealership could not help me out with the sensors and connectors.
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
I have this issue with the melted sensors and connectors. Could you provide the sensors and pigtails you got from Amazon? The local dealership could not help me out with the sensors and connectors.
If you want to support a vendor who supports this site: OE DPF Pressure sensor set
 
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