SQ7 AdBlue fault "reductant quality performance"

[Flobble]

I've had the "AdBlue fault: no restart in X miles" warning come up recently on my SQ7.

My local VAG independent garage (who I trust) found a faulty NOx sensor (replaced) and a faulty AdBlue injector (replaced), but the problem still occurs.

Plugging in to the OBD-II port reveals error 09953 Reductant Quality Performance". I bought this batch of AdBlue from the dealer, it was well within its expiry date, and the garage has confirmed that the Urea levels are in spec.

We think there is a possibility of out of date firmware on the NOx sensor, which may also recalibration and is giving erroneous NOx readings.

Problem is that needs a specific VAG tool (Flash box VAS 601 011) which no-one except the main dealers seem to have - I've called 3 other independents so far with no luck. And none of the local dealers can fit me in for several weeks (when they actually answer the phone... I've tried 4).

Any ideas on where I might get this done? It's a 1 hour process. Or other ideas to check?

My best alternative right now is that I resort to using Vag-Com/VCDS to reset the AdBlue system whenever the error pops up, and hopefully buy myself sufficient miles to make it through to a dealer appointment.

[Steve Q]

You could alternatively get a remap which does an adblue delete? Would cost around £300-500 I think 

[Dean Hill]

Flobble..

Hi, did you get this issue resolved? We have a SQ7 with same issue. After repairs around 50-100 miles the Ad-Blue shut down reactivates where it left off. Most recent warning went straight to Red warning - restart not possible, without any countdown 

[Flobble]

Hard to know. I hadn’t driven the car for ~2.5months until last week (abroad for a quite a while). The batteries were completely flat, so I charged them as best I could and jump started the car. Then, when I took it to the dealer for a hard look and a potential second NOx sensor problem, they found zero faults with the NOx sensors.

Could be the outside temperature having dropped 15 degrees. Could be the battery voltage dropping so low. I don’t really know, and haven’t yet done enough miles to be sure.

[cliffcoggin]

9 hours ago, Flobble said:

 The batteries were completely flat, so I charged them as best I could and jump started the car.

Do you often allow the battery to go flat? That alone might be responsible for the error message.

[Dean Hill]

Thanks Flobble

ive replaced nox sensor 2 as instructed by ODIS, but have since learned nox sensor 1 may be faulty (giving low readings) which causes the diagnostics to believe sensor 2 is reading incorrectly.

currently running tests. Will post update.

for reference this vehicle has no battery issue

[Flobble]

4 hours ago, cliffcoggin said:

Do you often allow the battery to go flat? That alone might be responsible for the error message.

No - that's a one off; I was overseas for a few months.

[Stevey Y]

6 hours ago, Flobble said:

No - that's a one off; I was overseas for a few months.

Hi if you leave any big Audi for a few weeks let alone months the battery will run down as the electronics on these vehicles are vast and many thats why there has been a boom in sales of trickle chargers, it keeps the problem at bay, most vehicle post 2017 suffer this problem.

Steve.