Diesel Exhaust Fluid module

224092 · Apr 14, 2020

My Touareg back in VW Service again and still carrying warranty so I don’t know what DEF module does do? It been since month now. Is something relate to computer control of AdBlue?

My computer on dashboard kept alert that AdBlue is low (100 miles left until engine turn off) but I checked my AdBlue tank level is full. Do you think DEF module need replace?

I just want know what’s does do with it?

chewblekka · Apr 15, 2020

Sounds like an issue with the DEF level sensor or the control module. Enjoy the fact that you have extended warranty.

224092 · Apr 15, 2020

They mentioned already replaced DEF level sensor so hopefully it’s DEF control module if not then I don’t know what else could be.

When I bought used Touareg and it was already engine light came on which was N0X sensor and other relate emission issues and AdBlue injection line filled of crystallized (sit at auction or dealership for long periods) so Huntsville (Hiley) VW Service didn’t their job in four months even don’t have diesel mechanic certification. I went other VW Service where provide diesel parts and they discovered Hiley VW Service doing dirty business.

chewblekka · Apr 15, 2020

Glad I got a tune to disable all that emissions bollocks.

nickyt · Apr 15, 2020

I hope the dealer checked the wires between the def sensor and the def module. Otherwise, you might be hearing that the new def module did not fix it.

224092 · Apr 16, 2020

Hopefully, able fix it and back on road again.

Also I noticed people delete their AdBlue system on Touareg I don’t know how it can affect? Does will make more poison in my Touareg?

chewblekka · Apr 16, 2020

I’m not sure I understand - what poison are you talking about?
If you delete/disable the adblue system with a tune and DPF removal, obviously some more emissions will exit the tail pipe.

224092 · Apr 17, 2020

Sorry my grammar not clearly but understood maybe one day I will do after warranty expires

ToolmanJohn · Apr 17, 2020

When my 2013 was only a baby. I had the AdBlue low level come on, about a week after a service visit. Odd. Brought it back, and they filled it, and cleared the code. Drove away from the dealership, and 2 miles away, LOW AdBlue level comes on again. I took it back, and they had it for three days, and it required a reflash of the ECU with support from Germany to get it sorted, I never had a problem with the level sensor since. But I did have the AdBlue tank heater replaced twice. All under the warranty.

nickyt · Apr 17, 2020

^^Yes. VW had to reflash the controllers. The early software was buggy.

Also, the early adblue heaters were defective. The adblue was corrosive and slowly destroyed the heater. After the court order that added the extended emissions warranty, VW commissioned a new heater, one that does not self destruct.

Vkvanoort · Aug 11, 2021

when was this? We have a 2013 and I thought everything was replaced and now my heater is going out and needs to be replaced on my $. thanks
Kay

224092 · Apr 17, 2020

That’s what I thought.

224092 · Apr 21, 2020

I just got my Touareg back yesterday. ToolmanJohn and Nickyt just exact what you mentioned. They had to replaced DEF Module and AdBlue heater after all just working again. I am glad they know what they are doing.

VW2015DM · Jan 14, 2021

Hi, i have a 2015 tdi Touareg and its been to the shop for the def system having issues. After we add def fluid and drive it a ways the engine light comes on then the def system light comes on. They have changed the nox twice and now rhey are telling me its that we are not buying vw exhaust fluid is the cause. Anyone else have that isuue? Thinking about doing a delete kit because it has cause so many issues.

Black Grouse · Jan 14, 2021

It's BS about not using VW Adblue/DEF - it's an international standard and widely available.

ToolmanJohn · Jan 14, 2021

It's not the DEF fluid. My 2013 was less than 2 years old and the DEF warning light would not shut off. This was just after 20000 mile servicing too, the day after!! They had filled the DEF tank, but the service light came on the following day. I took it back, and they reset it, said it was fixed. I picked it up, again, and a few miles from the dealership, again the DEF warning comes on. Took it back the following day, they had it for 3 days. It got re-flashed to fix the problem, and it never happened again.
Maybe your service department is swapping components hoping the problem goes away.

volkswagens-for-life · Jan 14, 2021

I've heard of many issues from not using Volkswagen def and using crap crap instead

TurboABA · Jan 15, 2021

I have never heard of this. Got any examples?
As others have said, DEF is a "standard" formulation.... it can be old but that's about it.
Unless you're buying it on a street corner from a crack head in a 2L bottle, I can't see how the "brand" is a factor.

TommiT · Jan 15, 2021

It's wee not crap.

volkswagens-for-life · Jan 15, 2021

I've just seen all kinds of threads all over the internet when it comes to German diesel engines being more finicky about not using OEM stuff. I know it's all urea and super simple but I've seen too many threads online where they had issues and the issues were stemmed from using an off-brand, like peak, where I just stick to OEM in this instance

TurboABA · Jan 15, 2021

Strongly disagree.
Just because users fail to diagnose a problem correctly and jump on the "non VAG branded DEF killed my [insert component like heater \ injector \ pump here]" and I've only used VW DEF since, doesn't make it a fact.

If you personally get piece of mind using VAG DEF, that's fine and I can understand that.... but I'm raising the BS flag on these folktales!

Does VAG have a proprietary specification for DEF which they either manufacture to themselves or have a dedicated supplier make for them?

volkswagens-for-life · Jan 15, 2021

Like I said I don't have any hard reasoning other than I've heard of too many failures that have been blamed on using El cheapo DEF. I've never personally compared the chemicals as I don't really care to since Volkswagen gives me free stuff. I'll be deleting that system shortly anyhow.

Black Grouse · Jan 15, 2021

I've not heard any such issues with the fluid in the UK - making Adblue/DEF to the standard specification isn't rocket science and it's used in large quantities by diesel trucks in Europe.

The biggest cause of issues with Touareg's Adblue/DEF system seems to be the heater circuits in colder climates plus the stupidly located filler under the boot/trunk floor.

TurboABA · Jan 15, 2021

But you're only using VAG def because it's free.... Not because it's the only one that works... That's a significant detail in my view. You're misleading the OP by not disclosing that!

volkswagens-for-life · Jan 15, 2021

That's not quite accurate, even if I had to pay for it I would probably still be buying the VAG DEF just because of things I've read online of other people having issues using knock-off stuff. And like I said I might be completely unfounded in my belief but better to play it safe than sorry.

chewblekka · Jan 15, 2021

What’s a DPF/DEF system?

TommiT · Jan 16, 2021

Not quite sure how one could really bugger up the production of a liquid that is 67.5% deionised water and 32.5% urea!

Vkvanoort · Aug 11, 2021

So I have a 2013 VW Touareg diesel . The heater (def) add blue stopped working and getting replaced to the tune of $1000! We are over 120.000 miles. Is this highway robbery or about right . Love this car but. ..gulp

volkswagens-for-life · Aug 11, 2021

that is on par with what I would expect for the heater replacement. No more emissions warranty?

C-ya · Aug 11, 2021

When was the dieselgate fix done? There is a 4 year/48,000 mile warranty for the engine and all emissions items under the settlement. Check your VIN here: VW Emissions Modification Lookup

Vkvanoort · Aug 11, 2021

C-ya said:
When was the dieselgate fix done? There is a 4 year/48,000 mile warranty for the engine and all emissions items under the settlement. Check your VIN here: VW Emissions Modification Lookup

Thank you for this link. I did and I am out of warranty but not by much. Oh well I tried.

Vkvanoort · Aug 11, 2021

attitude huh. What I read is 10 years or 120,000 miles and we are over 120,000 miles. Was just asking not complaining about the $.

volkswagens-for-life · Aug 11, 2021

That's the powertrain. Not emissions. Regardless c-ya already gave you a solid answer.

$1k for adblue heater is on par.

MonsterHooligan · Nov 1, 2024

224092 said:
My Touareg back in VW Service again and still carrying warranty so I don’t know what DEF module does do? It been since month now. Is something relate to computer control of AdBlue?

My computer on dashboard kept alert that AdBlue is low (100 miles left until engine turn off) but I checked my AdBlue tank level is full. Do you think DEF module need replace?

I just want know what’s does do with it?

diesel exhaust fluid

Surprised not to find any A6 P204B threads or posts. For my 2014 3.0 TDI I called my dealer to check if I had the right part number & revision for the main DEF pump but when he put the code into his internal system (forgot the 3 letter name) he came up with G686 which translates to the Diesel Exhaust Fluid Injector 4H0131113A. Does anyone know where it's located on the exhaust system, do any of the cover panels need to be removed to see it?

chewblekka · Nov 1, 2024

I can tell you without looking into it further that G686 is not the injector, it’s a sensor. Sensors start with “G”, actuators start with “N”.

G686 is the redundant pressure sensor, which is part of the pump.

The DEF injector is basically directly under the drivers seat, not covered by anything.

Diesel Exhaust Fluid module

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