Adblue tank repair details

[dsgoody]

Yes, I actually had the P20F6 fault around 250km (apologies, car is currently set in km due to being in France) before the P20E8 fault. I've cleared both, and only P20F6 has returned for now.

The description for P20F6 was something generic along the lines of 'Engine Fault, Repair Needed' along with the engine management light being illuminated. Apologies, I can't remember the exact wording.

What I really need to do is get it connected to Diagbox and have a look at the output of the pressure sensor to see if it's reading anything at all, and manually check the operation of the pump. Of course, I can't do either of these until I get home.

[Paul-R]

The description for P20F6 was something generic along the lines of 'Engine Fault, Repair Needed' along with the engine management light being illuminated. Apologies, I can't remember the exact wording.

No, I meant the description from your code reader. That's what displays on the screen in the car.

[dsgoody]

Apologies.

P20F6 - DeNox system circuit - Leak detection
P20E8 - Pressure of the urea fluid - Urea fluid pressure too low

I topped the tank up only 1000 miles ago, so I'm not low on fluid.

[dsgoody]

I've ordered the cheapest second hand tank I could find as a quick fix for now.

If anyone has any of the pressure sensors to sell let me know, otherwise once I've confirmed that is the fault with my tank, I'll probably order 10 of them, sell the other 9 and fix my original tank.

[Paul-R]

Before ordering new pressure sensors and once you have your old tank off the car you should check the pump is still working and putting out sufficient pressure. There is information in this thread on how to do this.

[Gambit]

Hi

Similar problem what do I need from Amazon to make up DiagBox I ve got Android 10 tablet or windows 8.1 or 11 laptops.
I can get a tank at an afordable price but will need to activate the pump after instalation - my only OBD device is Carley

Regards

Pete

[Frankla 72]

Hi

Is OK to put wynn's crystal clean and protect in the adblue tank to prevent crystallization forming.
Thanks in advance
Paul

[Trickiedickie]

Hi

Is OK to put wynn's crystal clean and protect in the adblue tank to prevent crystallization forming.
Thanks in advance
Paul

It's more than ok it's really a must. So yes do it. Then every time you top up with say 10 litres of adblue pour in a 125ml bottle.

[Frankla 72]

Just to mention I bought a 2016 peugeot partner tepee ex motability wav I don't think it's been driving much since may last year because that's when the tax expired, the car is running great I'm just worried there might be a build up of crystallization so was wanting to use wynns with more adblue, the low warning adblue hasn't come yet so I don't know how much adblue is in it, I bought 5 litres of adblue was thinking of adding 1/2 of the wynn's bottle to the 5 litre of adblue then pour it in the car to see weather it take all 5 litres or not

[roslinde]

@roslinde
A couple of things...........
I have also seen/had the P20E9 error combined with the P20E8. P20E9 means high pressure which is often caused by crystals forming in the adblue tank etc and forming partial blockages, just as I mentioned in the post above. Also removing and cleaning the adblue injector is a good idea. Draining and refilling with fresh adblue and the additive is important.

With diagbox you must make sure all the error codes are deleted as some are 'temporary' and others are 'permanent'

Yes, I was thinking that too, that leftover crystals were causing blockages. It also sounds likely, considering the error disappears, then no issues for 100-200 km then it briefly reappears, then disappears again after a couple of drives. So perhaps the anti-crystal liquid is working its way through the system?
An alternative cause could be that I never purged the pump or tank when reinstalling it. Could it be that there are air pockets in the hoses?

I did not know there was an option to tell the car that the tank has been replaced. Perhaps to initiate purging of the system? Since the tank was completely empty, maybe there are air pockets?

After changing the pressure sensor, P20A9 00 occurred but also a different error P20A2 00 at alternating intervals. P20A8 has not occurred since replacing the pressure sensor as far as I can see in the log.
Neither P20A9 nor P20A2 occurred before changing the pressure sensor.

It is not clear to me what this P20A2 error is related to.

When the error disappears, check engine light, SERVICE and urea indicators disappear and car drives as usual for maybe 100-300 km. Then they may reappear, usually within 15 minutes after starting the car. If the countdown starts, it rarely counts down more than 50 km before the error disappears again. I have never had to manually reset the countdown, as it disappears on its own.

I checked the ad blue injector and it is clean as a whistle. When I originally changed the pressure sensor, I emptied refilled with fresh adblue + additive as recommended.
I did receive a new pressure sensor (4-7bar) but I have yet to change it but it seems this would be the next step, assuming that the sensor I installed is wrong.

Sometimes when observing the live measurements using the DiagBox, the urea temp sometimes shows 0 degrees. Could this be one of the causes of the periodic fault?

I guess the next step is to install the "correct" pressure sensor and perhaps verify that the pump is in fact working as it should. But I would be surprised if it isn't, otherwise I doubt the error would disappear for several hundred km. Unless it is on its last legs?

Final resort would be to swap the tank, as it is easy and the tanks are relatively easy to buy brand new. But it would be a shame to give up this far into the project.

[dsgoody]

A quick update on the outcome of my AdBlue tank issues. I made it back from France using FAPLite to clear the codes every 200 to 300 miles, resetting the countdown. My cheap replacement tank was also faulty, throwing our low pressure and circuit board codes even after being coded to the car using DiagBox (viewtopic.php?p=842147).

I decided to order one of the Chinese sensors for my original tank, and despite testing my pump by throwing 12v at it, this also didn't resolve the issue. I ended up ordering another second hand tank, this one finally works! I suspect most of the issues with these tanks, if not the pressure sensor, are PCB related.

[Paul-R]

I suspect most of the issues with these tanks, if not the pressure sensor, are PCB related.

This is something that Tom309 put forward a few years ago.

[Martin Cheney]

Following a low adblue pressure fault on our C4 Picasso I had a chance this weekend to investigate the issue. Having removed the tank and opening up the pump unit I was able to do some basic checks to confirm if my issue was in fact a faulty pressure sensor. I hooked up a pressure gauge to the pump outlet and using a nominal 14volt bench power supply I powered the solenoid and pump and was able to observe 8 to 9 bar on my gauge proving the pump was OK.

I then powered the pressure sensor with a separate bench power supply (set at 5v) and under pressure the output was 0.4V so faulty.
I didn't have a replacement unit to install immediately and was thinking could the sensor itself have become blocked with adblue crystals, with nothing to loose I removed the sensor and gave it a really good soaking in hot running tap water. The result ended up with the sensor coming back to life...outputting about 4 volts at approx 6-7bar.

Unit is fitted back on the car now and everything is running fine with no faults....... How long this will last I'm unsure but I will run it and see.

Hope this may help someone else if they get stuck and have the equipment to electrically test the unit.

[CitroJim]

Hope this may help someone else if they get stuck and have the equipment to electrically test the unit.

Thanks Martin That is very good to know and follows my principle of 'when it's broke it's always worth looking for any way possible to fix it...'

Another most useful contribution to what is now the AdBlue Tank bible

[Martin Cheney]

Update on the flushed out pressure sensor.... it has stopped working after 4 days.

Will now be fitting a replacement, if anyone did by a few spares and are looking to sell on then please let me know.
In the mean time I'll will search for replacements on line for both the internal original replacement but also external third party sensor method of OP.