P204F00 error code please help

[Staciew1985]

Hello, looking for some advice if possible because my Audi A4 seems to just be giving me problem after problem at the minute. Back story for context - Had mutiple issues over the last two years with the DPF. It’s has two regens done and recently it came up with DPF error again so this time I decided to go an actual DPF cleaner company. The man came out cleared the fault code and cleaned dpf but within 10 miles of driving my eml pinged back on. I called back and asked him to look at it again which he did. He told me that the fault was infact my ad blue had crystallised (don’t know how true that is) he said he had cleaned it now and he would only charge me a call out fee. The car drove lovely for about a week and then ping a new message saying ad blue fault with the EML which hadn’t appeared previously. I have taken it to a basic garage today who plugged it in and the code they are getting is P204F00 but he said they couldn’t get any more info and I’m better going to Audi specialist for it as not really their area of work. Just wondering if anyone could shed any light on this and does it all sound legit in regards to the clean I had to then have caused this issue. Any help much appreciated
Thanks

 

[Dav-Tec]

Couple of things it could be but hard to diagnose without an autoscan giving me more information.

A simple ECU software update may fix this, had it a lot on the transporters the emissions system software was plagued with bugs.

May need the adblue tank cleaning as it could of crystallised in the tank.

Yes dpf issues can cause adblue not to work but we've also seen it where adblue issues can be misdiagnosed as a dpf fault.

 

[Staciew1985]

Thanks for the reply - I’ve recently had the DPF cleaned and engine light came back on after the clean. The cleaner guy then said my ad blue was crystallised so he cleaned that also. Worked ok for week and drove lovely now this new code up as in post. Before the dpf clean it was code P2020 so completely diff and that one is now gone