Hi, I have a 2019 C4 Grand Spacetourer 1.5 Diesel. The dreaded "Emissions fault: Starting impossible in 700 mi" has come on. A cheap reader showed up an error code of P20EE, I cleared the P20EE code and it's not come back. As I mainly do short journeys I though that the UREA injector might be clogged up as seen on a couple of YouTube videos. I took off the injector and as you can see it was very clogged up. A short clean later and I embarked on the most awkward replacement of the clamp to hold it back in place... maybe carrying this out from above was the wrong idea
Onto my question. From what I've read, the next step would be to use a fancy box of tricks and correct the denox nox adblue fault. Is this correct?
To note: My tank has the fill point alongside the diesel and the cap is vented, so I'm hoping it's not an issue with the tank.
You might have got luck, then again...! If it stays away all well and good, but if not then yes, you need a better scanner to read the live data. That code is pretty much just generic de nox not working, which is not that helpful!!
There may be 2 further digits on the end of this code which if the case, would provide some additional info, however this code P20EE on its own means a guided diagnostic procedure needs to be followed using Diagbox in order to determine the issue.
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Thanks Marc, On the cheap reader it just had that code, no other number/letters. Does it have to be a Diagbox or is this a general term like Hoover? ie is it worth me ringing round some garages rather than go to Citroen?
You will need Diagbox which is the proprietary software used with the VCI (diagnostic tool hardware) by PSA for their vehicles. Generic code readers don't have the capability and not all aftermarket professional tools either - and this also depends on whether the aftermarket garage bothers to pay to update their software for the latest systems and vehicles - so very hit and miss.
With a dealer, they will charge you £125 inc VAT for up to an hour of diagnostics - see their published prices here for confirmation of this:
So that should provide ample time to run the diagnostic and take any action required by the results using the diagnostic tool.
On another note, when you get it sorted, I strongly suggest you introduce an Adblue additive into the UREA tank that can prevent crystallisation and clean the Adblue system. I use the Wynn's personally, but with Wynn's, make sure you buy the correct one as they have one for commercial vehicles and another for passenger vehicles:
Cheers Marc, I'll take it up with Citroen and put some additive in the tank if I keep the car. As I only do 2x 6 miles a day to work it might be best to swap it for a petrol version as I need the seating arrangement. It's a shame that they've stopped making them.
For reference, this guy on YouTube has fixed several vehicles in his videos that have had this problem. Is that a Diagbox hes using?
That's not Diagbox, but he is using a professional level diagnostic (X-431 EURO TAB III) which is about £6k! and he will still need to update the software after 2 years - so as you can see this level of equipment is expensive as they have to keep updating the software to deal with the latest systems.
He's basically checking and cleaning the Urea components after ascertaining that the Adblue tank is actually ok, then resetting the relevant codes and reinitialising the system. So hopefully that's a result.
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There's one of his Vids where he gets a bit off track with the AdBlue diag, but there is some very good diag info in the comments, I'll see if I can find it again.
I think he made reference to that previous vid in the one posted above Richard - says Cats and the later emissions system wasn't really his thing, but has had to move on with the times.
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It's all a bit annoying that the design is such that the car can become undriveable without a costly repair. Mine's only 4 years old. 36k miles, FSH, mainly short trips, but with many longer trips throughout a given month. I guess it's the last diesel I'll own. Time for a call to Citroen on Monday.
For me it's that the injector can become so clogged up with soot. Bad design/not being fit for purpose of the average driver. Ah well, lets see what Citroen have to say.
The fault P20E8 is always temporary unless you read the fault code in the same cycle as it was triggered but because you have cycled the key at least once since the fault has occurred its causing it to not be active. It is enough to cycle the key once after the triggering cycle for it to go temporary therefore drawing the conclusion that P20E8 is a temporary code and you just gotta refill tank and reset the denox system is incorrect.
However sometimes although very rarely it is truly caused by low fluid but then the car will warn you well in advance (2400km) before that you have to refill so most customers are well aware whether low fluid level has a play in the fault or not. You can check this in Denox 2 parameters, the tank only measures up to 6.1L so if the parameter says above 6.1L then you are good. You can also see in the fault code freeze frame data whether the level was low at the time of setting the code
Sometimes it is easy to confirm whether it is the tank by going into Denox 2 parameters and checking for Adblue temperature and fluid level, if any of those are 0 (default value) when they clearly shouldn't be, the tank has an internal fault and should be replaced. The fault code P20E8 is easy to misunderstand if you take it literally, there is an absence of pressure but it is only the indirect reason for triggering the fault code. If the Adblue-system senses a fault within the tank (temperature, level, heater, continuity, integrity or software fault) the whole system shuts down and sets the fault code P20E8 - Low pressure but a better fault code definition would be fault detected within the Adblue tank causing the system to shut down the tank assembly, as I said sometimes you can see the fault yourself by looking at urea temp and urea level but sometimes those two values are real and working and something else is wrong within the tank which you can't see, if that is the case then check power and grounds to the tank, check adblue injector, check for Adblue leaks and check for NOx sensor correct NOx data during driving just to make sure you are not missing anything, if all seems OK the only thing left is the tank itself. The pressure and level btw you find in Denox 2.
We / I diagnose and replace literally 100s per year working at the Peugeot dealer.
Also for your information you seemed to be confused about Adblue / urea vs PAT / Eolys / Additive. All PSA diesel cars since long and even to this present day with the cars rolling of the factory floor still have the additive / pat / eolys fluid and since 2013 also come equipped with the Adblue system side by side with the eolys, one as a fuel additive and the other as an exhaust aftertreatment as was the case for the car you had which had both Adblue and Eolys and the replacement action you did with the scanner was for the Eolys tank and not the Adblue tank but it seemed to have reset the Adblue system as well which is not supposed to happen and is weird, seems the scanner isn't quite adequate for PSA diesels.
The thermal ageing of the denox converter is a value that starts at 100 for a new one and starts counting down to 0 as the computer calculates its aging / degradation. The calculation is based off of theoretical NOx generated (because there is only 1 post sensor on these unlike the new ones which have 1 pre and 1 post) calculated from a table in the ECU and comparing it to the post cat NOx value and seeing how effective it is in comparison to what it is expecting. As I said this value is counting down to 0, when they get to around 25 they are usually junk despite having 25 counts left.
More than likely this customer will continue having trouble with the code coming and going until the tank is replaced and nothing you did really helped the P20E8 fault code itself considering that it means internal tank fault. However regening the DPF and cleaning the injector is a good thing in general so it's not all wasted time and money.
Replacing the Adblue tank with a used one is not worth gambling with considering they may develop the same fault quite quickly, it's better to buy a new tank however it is ridiculously expensive and not logical to replace unless you can get warranty or the insurance company to pay for it leading to most people just doing Adblue OFF reprogramming when this fault occurs and not being able to pay for the proper repair.
And
Btw 4 bar adblue pressure in Denox 1 is a replacement / placeholder value and means the system has not yet activated and currently has 0 bar of pressure because 4 bar is the lowest the sensor can read and a working system ALWAYS starts at 6 bar and drops to around 5.5bar during use because of slow bleeding of pressure through Adblue injection but is then triggering the pump to build pressure again back to 6 bar. Therefor 4 bar = 0 bar.
Also you filling the Adbluetank was not necessary for the sake of fault finding or diagnosing because the tank already had sufficient fluid level to work as you can see in the Denox 1 parameter you are reading at 2:03 where volume of fluid measured in the reservoir is 6.1 which means it's at 6.1L or above because the level sensor only measures a max of 6.1L, so if you see 6.1 its sufficient for system to activate. That being said ofc filling the tank is a good thing to do anyways just a bit sour for the customer if the fault returns and having paid for the Adblue and ending up doing Adblue OFF
The pressure building does not take place until all the right conditions are met, you can see when they are met by looking in Denox 2 at 2 parameters, 1 being Authorization of pressure based on temperature and the other being authorization of pressure based on pressure, only when both of these turn to 1 / ON / YES does the system start and build pressure and start injecting, as long as any of them are NO the system is not turned on.
Authorization of temperature turns to YES when the exhaust temp reaches 200C.
Authorization of pressure turns to YES when all internal tank parameters are correct such as temperature, heating pad circuit and feedback loop, continuity, software, Adblue quality etc.
