DEF / AD BLUE Future Problems?

[A1sailor]

2015 Q5 TDI, 200,000 KM, Emissions warranty over.
Is it a matter of When not If that problems will happen with the DEF system?

What type of problems can I expect and any ball park costs expected?

DEF was replaced at 185,000 under warranty, NOx sensor at 189,000 km under warranty.

In southwest Ontario, cold here in winter.
Does DEF system have more issues in cold climate?

DEF heater, pump I hear can be issues.

No current problems, would like to drive vehicle for another 4-5 years, extra 80,000 km.

 

[TurboABA]

No one can predict it for you.

DEF was replaced at 185,000

Why are you saying that the fluid was replaced under warranty?
There are several sensors (quite expensive) on these setups which are a wear item, and can fail at any time, especially at that age\mileage. There's a high probability that you will experience this within the next 5 years. If you don't do your own wrenching, a single sensor replacement will run you $1k. Which NOx sensor was replaced? There's a good chance the other one won't be far behind it.
Track your DPF stats, regen cycles, DEF usage in order to "gauge" how healthy things are.

 

[A1sailor]

Turbo ABA, thank you for your reply. My error, the DPF (not DEF) was replaced under recall warranty "23Z8 oxygen sensor relocate via DPF replacement." I decided to do this at 175,000 km before the emissions warranty expired.

The recent replacement of the NOx sensor was number 2, no indication on paperwork of bank #, it was mentioned as G687 and it was replaced at 190,000 km in Nov 2024. They did mention that the sensor was seized and required extra time and heat.

In addition NOx sensor bank 1, number 2 was replaced prior at 84,000 km in Nov 2018.
The above is the entire emissions warranty work done to the vehicle from Sept 2018 to date, bought it as a CPO.

I have the scan tool, I will need to research how to monitor the readings that you mentioned.
Thanks

 

[TurboABA]

There you go.

So the same NOx #2 has failed twice. If you want to gauge your failure rate on that, you have a frequency.
VCDS readings can be easily taken to show all the data that I mentioned.
I'll give you a sample off my A6 as a guide.

               Address 01: Engine  (4G0 907 401 N)

14:14:08
  IDE00432   Particle filter: time since last regeneration 65328 s
  IDE00433   Particle filter: oil ash volume 0.04 l
  IDE00434   Particle filter: soot mass calculated 16.49 g
  IDE00435   Particle filter: soot mass measured 1.56 g
  IDE00436   Particle filter: kilometers since last regeneration 729586 m
  IDE00584   Distance driven since erasing DTC memory 4784 km
  IDE00603   Number of driving cycles since erasing DTC memory 95 
  IDE01922   Vehicle distance driven 141723 km
  IDE03386   Long-term adaptation of reduction agent dosage 0.98 
  IDE05857   DPF statistics: current measured charging rate 0.0576 g/km
  IDE06983-MAS05392   Diesel emissions re-treatment: status-Average distance between DPF regenerations 343 km
  IDE07197   Average reducing agent since lest filling 0.80 l/1000 km

 

[TurboABA]

I will need to research how to monitor the readings that you mentioned.

Ross-Tech: VCDS Tour - Advanced Measuring Values

 

[ZippyNH]

Question...do you park your car in a garage that's at least passively heated (sharing a wall with living space and insulated on the other walls)?
Living NH...I seemed to do much better with my DEF equipped Jetta, not burning out the in-tank heater that many people had issues with...
Unfortunately VW choose to use an electric heater rather than a coolant loop like most HD trucks....
My suggestion...keep the tank mostly full and hope for the best. The heater WAS available separately...but now it only available as a full assembly with the tank I believe for MOST if not all models

 

[TurboABA]

Both my 3Ls live outside year round.

 

[A1sailor]

TurboABA and ZippyNH,
Thank you for your answers.
I will connect my VCDS to check / monitor readings as suggested.
I will also call Audi about the DEF heater / tank for a cost.
Maybe a weight loss is an option to look at.

 

[TurboABA]

You said you don't have any problems... Why are you calling your dealer for some cost? What am I missing?

 

[A1sailor]

For budgeting purposes. If worst case on the DEF system is that the DEF pump or tha DEF heater fails then I would like to have some idea of cost.

 

[Lightflyer1]

Why not use some of our vendors here on this site? They're generally much cheaper than the dealer in my experience in buying from them. I use ID parts but there are others as well you can find in the vendor threads.

 

[A1sailor]

Good suggestion I will look. Thanks

 

[TurboABA]

You can't budget for anything, as you don't know what will fail or when. A NOx sensor replacement at the dealer will be $2500 (this is was VW invoiced for my Touareg - dieselgate covered). If a DPF fails, you're looking at a $3k part probably, if they can even get it...

If you're this paranoid about having something break on a 10 year old vehicle with 200k on it, unload it or trade it in on a Yota or something.

 

[A1sailor]

A Yota?

 

[Lightflyer1]

Toyota

 

[A1sailor]

Ha, ha, I like your sense of humor.....BTW 2nd vehicle is an RX 350