Hi all,

The engine management light has come on on my 2019 smax diesel. I've run a forscan test and it's come back with error code P20EE (see attached).

 

I searched online and this seems to be linked to NOx sensor or adblue issues. 

 

Could this be linked to the cracked DPF recall? See my other post here 

https://www.fordownersclub.com/forums/topic/160142-2019-s-max-recall/#comment-1102398

Anyone got any ideas?

DOC-20250922-WA0001..txt

I cleared the error and it's stayed off for now 

Good to see it cleared, but It probably will return.

This won't be anything to do with the DPF.  That just collects soot.  It has no effect on NOx.

Could be a clogged ad blue injector.

The ad blue crystallises and clogs the injector, happened on my Focus 2.0 ecoblue.

That's if you have ad blue.

A bit like using Archoil as a fuel additive (for multiple benefits) I'd use the stuff that you add to AdBlue to prevent crystallisation:
https://www.amazon.co.uk/Wynns-Crystal-Preventative-Crystallisation-Additive/dp/B0BV7BNHDT/
I don't have any experience of it but if I had Euro 6, I'd use it.

 

2 hours ago, Shearers said:

A bit like using Archoil as a fuel additive (for multiple benefits) I'd use the stuff that you add to AdBlue to prevent crystallisation:
https://www.amazon.co.uk/Wynns-Crystal-Preventative-Crystallisation-Additive/dp/B0BV7BNHDT/
I don't have any experience of it but if I had Euro 6, I'd use it.

 

I acually used this but still had the problem of injector clogging up.

29 minutes ago, MarkRS9 said:

I acually used this but still had the problem of injector clogging up.

Sorry to hear that so wonder if it's the specific additive package or it doesn't work at all or it was a more serious or different problem?

13 hours ago, MarkRS9 said:

I acually used this but still had the problem of injector clogging up.

What symptoms did you get out of interest?

I've got a 5 year old/40k diesel (non-Ford) that hasn't been driven for about 3 years.  Adblue not been topped up in that time either, counter still shows something like 6000 miles worth.  I've been concerned about it crystalising but there are no fault warnings and it's just passed MOT as well, with no issues on the short drive each way.

I do get a lot of water from the exhaust when running it on the drive.  Have wondered whether this is Adblue as I've never seen it this badly with any other car from condensation alone.  Coolant level hasn't dropped so it isn't coolant.

I slopped the whole 10L container in when refilling recently even though the dash reminder said to refill "3 - 9 litres", as I perhaps wrongly assumed it would cut off automatically. So maybe it overflowed and crystallised with oxygen in the air on the injector. I will try the additive if my light comes on again.

3 minutes ago, dave189h said:

I slopped the whole 10L container in when refilling recently even though the dash reminder said to refill "3 - 9 litres", as I perhaps wrongly assumed it would cut off automatically.

What would cut it off?  There's no mechanism inside a bottle like there is a forecourt pump.