Adblue System Fault - No Restart 1000km

**Silane** · 29-10-2018,12:32 PM

Hi Folks,

I could use some help, I have what appears to be a pretty serious problem with my car. On the motorway I got a fault, "Adblue System Fault, no restart in 1000km. When I got home I did a scan with an OBDeleven and got the following error code.

01 Engine

System description: R4 2,0L EDC
Software number: 04L906021FE
Software version: 8243
Hardware number: 04L907309
Hardware version: H23
ODX name: EV_ECM20TDI01104L906021FE
ODX version: 002007
Long coding: 0A194012242401080000

Trouble codes:
P204F00 - Reductant System Performance Bank 1
static

I had just put in adblue 2 days before I got the error, but I topped it up again and made sure it was completely full. I reset the error code and drove for 100km. The error code above did not return, but the adblue countdown has continued and is now at 800km. I also tried a hard reset on the reductant control module, the original error was on the engine module, but I wasn't sure if hard resetting that is a good idea.

I'm reading some horror stories about what this error can be, some people have paid upward of 2K to get NOX sensors and other parts replaced. Anybody got any ideas before I get the vaseline and go to the dealership?

**KevTrem** · 29-10-2018,12:50 PM

I have just had this fault on my 2015 A6 Allroad, for me it was the reductant pump that was at fault. It was replaced and problem solved. Cost for the pump was £600 supplied. I was told it could take up to 4 weeks for the pump to be supplied, it took 3 days.

Mine was P208B Implausible Signal

**KevTrem** · 29-10-2018,12:51 PM

There was talk of possible wiring fault, but after testing it was confirmed to be the pump.

**Silane** · 29-10-2018,12:57 PM

Thanks. I find it hard to believe its a part failure just after I topped up the tank, but I know that's what Audi are going to say too.

**KevTrem** · 29-10-2018,01:04 PM

Mine went and I hadn't even topped up the tank, only had the car since August, pump went beginning of October. Is your car still under warranty?

**Silane** · 29-10-2018,01:05 PM

Nope, mine's a 2014, so well out of warranty

**KevTrem** · 29-10-2018,01:14 PM

Do you have a local trusted independent that you could use? It was an indy that sorted mine out.

**Silane** · 29-10-2018,06:42 PM

I do have a good VAG specialist indy I use, I'll call tomorrow, it's a bank holiday weekend here. Typical! It's a 200km round trip to them though, but I might just chance it

**Silane** · 01-11-2018,10:26 AM

I took the car to the Indy I normally use and he said this combination of trouble code and adblue error is a known software glitch, and a SW update on the ECU is the fix, 20mins later the ECU was updated, the error was gone and I was on my way. So far I've done 120km and no re-occurence, so all looks good.

**Diddion** · 08-06-2019,07:00 PM

Hi Silane, I have exactly this fault on my 2014 A6 Avant, and the same error code so your post does suggest the same cause for my car. Could you just update on whether the ECU software update resolved the problem permanently? Thanks!!