Defective sensors and pumps in the AdBlue system of the Peugeot 2008 diesel regularly trigger warning lights and fault codes. In severe cases these faults even lead to starting problems. They often require replacement of expensive components such as the AdBlue pump or injector head. Repair costs can rise to a maximum of €3,000. Fortunately, there are practical solutions available and some owners are even entitled to compensation.
Why does the AdBlue system generate faults?
The AdBlue system reduces harmful nitrogen oxides in the exhaust gases of modern diesel engines. The system consists of a tank, a dosing pump, an injector head and sensors that measure the fluid level and quality. In the Peugeot 2008 BlueHDi, faults regularly occur due to defective sensors. These sensors report an empty reservoir while the tank is still filled. This leads to unnecessary warnings on the dashboard.
Crystallisation of AdBlue around the injector nozzle (the spray tip of the AdBlue system) is another very common cause. The fluid crystallises when it comes into contact with air. This causes blockages. It disrupts the correct dosing and activates the warning system. In some cases the control unit registers incorrect signals. Fault codes then appear even though there is no real problem.
‘ The cause is that the system keeps incorrectly indicating that the tank is empty. ’
Recognisable symptoms of AdBlue problems
The first signs of an AdBlue fault are usually clearly visible on the dashboard. The warning light comes on and a message about the AdBlue level appears. Normally this happens more than 2,000 kilometres before the level becomes critical. In the case of faults, this warning can also appear without reason.
Fault code P204800 occurs frequently in the Peugeot 2008 diesel. This code indicates problems with the AdBlue injection system. The fault often goes hand in hand with reduced engine performance. The car then switches to a limp-home mode in which the power is limited. In the most extreme scenario, the engine will no longer start at all. This problem can even occur directly after refilling AdBlue. The cause is that the system keeps incorrectly indicating that the tank is empty.
How can you fix AdBlue faults yourself?
For minor faults you can reset the system yourself. You will need an OBD2 diagnostic scanner. This is a device that you connect to the diagnostic port of your car, usually under the dashboard on the driver’s side. Connect the scanner and establish a connection with the engine management unit. Navigate to the menu for the emissions control system (the part that monitors emissions) and select the option to reset the AdBlue system. Then switch off the ignition and wait about thirty seconds before switching it back on.
This method mainly works for warnings that are caused by temporary sensor errors. The warning light usually goes out immediately after the reset. The warning can then return. In that case there is probably a hardware defect. Always check the actual AdBlue level first before assuming that the warning is unjustified.
Do you get a warning while driving that the AdBlue level has reached zero? Then do not switch off the engine straight away. Continue driving to a filling station, garage or home and only top up there. Once switched off, the engine may refuse to restart. The system will then detect a critically low level.
How much does AdBlue system repair cost?
The cost of professional repair of AdBlue faults varies. The defective component determines the price. Replacement of the AdBlue injector head is a common solution. This repair resolves fault code P204800, a fault indicating that the injection system is not working correctly. It often solves crystallisation problems and, including labour, usually costs between €500 and €1,000 at a specialist garage.
Replacement of the complete AdBlue tank with the associated pump unit is the most expensive repair. According to quotations from authorised Peugeot dealers, this job can cost up to €3,000. The tank is often integrated with the pump unit. Both components therefore have to be replaced together. A defective sensor can sometimes be replaced separately for an amount between €200 and €400.
Possible compensation for owners
Stellantis, Peugeot’s parent company, announced in October 2023 that it was prepared to compensate Italian owners. The compensation applies to diesel vehicles with defective AdBlue systems. The compensation covers up to 100 per cent of the replacement costs. The age and mileage of the vehicle determine the amount of compensation. Always keep all maintenance documents and quotations.
Contact an authorised Peugeot dealer. Check whether your car falls under this compensation programme. Ask specifically about service bulletins or recalls relating to the AdBlue system of the Peugeot 2008. Even outside official programmes, goodwill from the manufacturer can sometimes be an option, for example a partial contribution towards costs in the case of known design defects.
‘ Those impurities accelerate crystallisation and can damage the pump. ’
How can you prevent AdBlue problems?
Regularly topping up AdBlue helps prevent sensor faults. Top up before the level becomes critical. Always use high-quality AdBlue from reputable brands. Avoid cheap alternatives. These contain impurities. Those impurities accelerate crystallisation and can damage the pump.
When filling up, make sure you do not spill around the filler opening. AdBlue crystallises quickly when exposed to air. The crystals then contaminate sensors and the filler opening. Wipe up any spilled fluid immediately with a damp cloth. Have the AdBlue system checked at every service. Early-stage problems can then be detected in time.
Avoid long periods without using the car. AdBlue can go off over time. This happens especially at temperatures above 25 degrees. Drive the car regularly and make sure the system remains active. If warnings keep appearing without a clear cause, it is wise to have the system read professionally. Special Peugeot diagnostic software is used for this, a computer programme that provides deeper insight into the AdBlue system than an ordinary OBD2 scanner.
When should you go to a garage with AdBlue problems?
The warning light will sometimes keep returning after a reset or after topping up AdBlue. In that case, go to a garage. Reduced engine performance or a limp mode also require immediate professional diagnosis. An authorised Peugeot workshop has specific software to read out the entire AdBlue system. The workshop can then offer targeted solutions.
Preferably choose a garage with experience in diesel engines. Experience with emissions systems (the components that clean and regulate emissions) is also important. Request a quotation in advance for the diagnosis and any repair. Compare prices between authorised dealers and specialised independent garages. Check whether the garage uses original parts. This is important for the service life of the system.
AdBlue faults in the Peugeot 2008 diesel are annoying. These faults are often solvable with the right approach. Act in good time and have regular maintenance carried out. This reduces the risk of expensive repairs and keeps your car reliably on the road.
Frequently asked questions
The most common ‘symptoms’ are an illuminated AdBlue or engine warning light and messages on the dashboard about an AdBlue fault or limited remaining range. Power loss often also occurs, or the car goes into limp mode. In some cases the engine will no longer start after a certain countdown, despite the AdBlue having been topped up. Crystallisation or leakage around the AdBlue injector can also be visible.
If you ignore an AdBlue fault, the car can go into limp mode (reduced performance) and eventually refuse to start once the system thinks the AdBlue tank is “empty”. You can then unexpectedly break down or be unable to restart the engine after switching it off. Driving on for a long time with a genuine system fault can also lead to further damage to parts of the AdBlue/exhaust system, which can mean expensive repairs (up to around several thousand euros). You also run the risk of failing the MOT and potential problems during emissions checks.
Possible repair options for an AdBlue fault include resetting the system with diagnostic equipment, cleaning or replacing the AdBlue injector head and, in more serious cases, replacing the complete AdBlue tank/unit. A simple reset or diagnostic check usually costs from a few tens of euros up to a couple of hundred euros. Replacing only the injector head generally falls roughly in the range of a few hundred euros. Replacing the entire AdBlue tank can, depending on make and model, cost up to around €3,000.
Minor AdBlue faults, such as an error message without a real problem, can sometimes be resolved by topping up AdBlue and resetting the system with an OBD2 diagnostic tool. If the warning keeps returning, you see fault codes such as P204800 or the engine will no longer start, then a visit to the garage is necessary. Serious faults are often related to defective sensors, injector head or tank and require professional repair.
Check and top up the AdBlue reservoir in good time with certified AdBlue and avoid letting the level fall to (almost) zero. Keep the filler opening and surrounding area clean to prevent contamination and crystal formation, and always close the cap properly. Regularly make longer journeys so that the exhaust and AdBlue system get properly up to temperature and crystals have less chance to form. If warnings occur repeatedly, have the AdBlue system read and checked preventively at an authorised Peugeot workshop so that sensors, injector and tank can be replaced or cleaned in good time.