Adblue tank repair details

[earlsgate]

The pump doesn't work if all conditions are not met, so with the default zero value urea temp it won't cut in even when other conditions are achieved

[toader02]

Hi everyone. I have a 2015 Peugeot 308 T9 1.6HDi 88 kW with this awful low UREA pressure error.

I removed the tank and replaced the temperature sensor as it showed around 200ohms. The heater thermistor was faulty, so I replaced it with an A/C thermistor. Everything else seemed fine (the pump and solenoid valve operate at 12V, etc.), but due to lack of time, I didn't check the internal heater circuits (pump, accumulator, solenoid valve, output) or the pressure sensor (also because i didn't have a gauge on hand). The fuel level sensor shows OK in the diagnostics, so I assume it's working.

I added about 10 liters of AdBlue (maybe a little less), but the error persisted. I believe I can hear the pump when I turn the key but can't tell over the diesel pump. However, a few times (but not always), after I turn the (warm) engine off, I can hear a click and the pump for a few seconds near the back right wheel.

I don't have Diagbox, only Delphi/AutoCom, but I can read all the CAN values. Over on the elektroda forum, people are saying that after the UREA warning light is displayed, the temperature should drop to 0, indicating the UREA computer is turned off by the ECU.
The pressure is a constant 4 bar no matter what I try (as expected), but the temperature is always correctly reported and close to the ambient temperature, so I assume it's fine. So the computer doesn't shut down even though something's broken, as others are suggesting? Is it a good assumption that if I hear the pump when turning the engine off, the system is getting activated?

After the repair, a new error code also appeared: D200. I have no idea what it is, and I haven't found anything on the internet, might be an autocom issue. Could it be an actual fault?

What do you think? My next plan is to change the pressure sensor with a new one before the MOT. Could it be those small heating circuits I haven't checked? Strange that I can still read the correct temperature even though other colleagues couldn't when they had errors, after 30 seconds...

[Tpereira]

Hi everyone, got a P20E8 00 code, already change the whole tank but can't code it, diagbox says iddle too high.

Pressure stays at 4bar, any ideas?

[Paul-R]

What version of Diagbox are you using? Is the VCI full chip?

When you do a scan for errors, what results do you get?

[Tpereira]

I'm using the latest version available, also tried a launch tester but it just don't let me reset the tank.

When I scan for failure everything comes with no faults.

Iddle is at 810-50.

[perfidus]

Hi, you said that you got P20E8 00 before changing AdBlue tank. Now you have no fault. What makes you think the tank isn't coded after all? Is it something that I did not follow in what you describe? Or did you mean no OTHER fault besides P20E8 00?
You have engine idle at 810-850 RPM after coolant is up to temperature (80 degrees)?

[pnovy]

Hello,
I encountered the same issue in my Peugeot Boxer 2.0 (campervan) - P20E8 error.
I removed the tank and measured all heating circuits and sensors. I found a fault in the thermistor on the heating plate (yellow wires). I cut off the faulty thermistor and added a new one.
I reinstalled the tank, but unfortunately after clearing the fault, it still comes back after a few kilometers of driving. The only thing that confirms that my partial repair was successful is that now the correct temperature is displayed instead of 0°C.
I monitored the parameters with a Launch scanner - the pressure is 4 bar.

While removing the tank, I also measured the AdBlue line (to injector) heater and it turned out to be broken (open circuit).
Does anyone know if the AdBlue tank should operate normally with a faulty line heater, and could this cause the P20E8 error?

[perfidus]

Hi, the heaters are monitored and an open circuit on one of them will shut down the pump control and give you that error. Check the pipe for visible damage in the lower part near the injector. Maybe you can fix it if you see the damage.

[pnovy]

Hi, thank you. I’ve ordered a new pipe and I’m going to replace it. I hope there won’t be any more issues

[pnovy]

After replacing the AdBlue hose, it started working
Thanks.

Two tips that might be useful. Right after replacing the cable and turning the key, I immediately noticed that the ‘Check AdBlue system’ message disappeared. The only thing left was the ‘Check engine’ light, which I later cleared. Another thing is that I believe the thermistor failed in autumn in my case. I left the car for the winter, and since the system wasn’t working properly, it didn’t drain the urea from the system. This caused the fluid to freeze in the hose and damaged the heater.

[Paul-R]

Thank you for letting us know.

[altisimo]

Hello. First of all, thanks you for your ideas. I'm hoping you can help me out. My car is a 2020 1.5 BlueHDi, 6.2. It's giving me fault codes P20E8, P208E, and sometimes P20A2. I've replaced the injector, drained the AdBlue tank, refilled it with fresh AdBlue and added anti-crystallizing agent. I have tested the amount of adblue injected using Diagbox, and the result is right but on the road It doesn't work properly. On the first start of the day, it doesn't build up pressure, only 4 bar. If I turn the engine off and restart it, it reaches 6 bar, but as it injects AdBlue, the pressure drops to 4 bar and doesn't recover. I don't hear the system trying to increase the pressure. Do you think it's a sensor issue?

[Trickiedickie]

Sensor issue, yes very likely. You could try using a second hand replacement sensor if you have access to another.

Do you have Diagbox? If you do I would try to re-initialise the adblue pump/tank unit.

Also, go back and check the adblue injector just in case it has become blocked with crystals.

[altisimo]

Thanks for your answer. The injector is fine. I have Diagbox and will try to re-initialise the adblue pump-tank unit. I have also ordered a pressure sensor. I'll let you know if it works when I receive It and install It. Thanks again!!

[01484]

Hi guys i am new to this forum. After doing hours of research I think this maybe the solution for me too. I have a Peugeot 2008 bluehdi 2015 diesel. I am getting urea light service light and engine management light too. After plugging in diagun x431 launch tool I can see low pressure fault code. I haven't taken the tank off yet will do tomorrow. On the diagnostic it's 4 bar and doesn't move. I am suspecting the pressure sensor. How can I test the pump? By attaching 12v car battery to it? I can do the mods to the tank that are shown at the start of the forum but I'm struggling to understand and follow it. If I buy a pressure sensor and fit that and delete the fault codes will that fix it? Or do I need to modify and add pipes etc to fix it? Thanks for your help and time any help is very much appreciated, been stressing from this fault for 2 days now . Was going to order a 2nd hand tank tomorrow but think I can save that money and try this.