Peugeot Partner and Citroën Berlingo AdBlue (DEF) System Faults
AdBlue is a critical component of modern diesel emissions control, introduced alongside the Euro 6 regulations to significantly reduce harmful nitrogen-oxide (NOₓ) output. Both the Peugeot Partner and Citroën Berlingo utilise an AdBlue (Diesel Exhaust Fluid) system that precisely injects the fluid into the exhaust stream to convert NOₓ into harmless nitrogen and water vapour. Proper maintenance of this system is essential to avoid fault warnings, limp-home modes and eventual engine immobilisation.
Common Faults:
- Internal corrosion or water ingress
- Short circuits or internal electrical faults
- Crystallisation of AdBlue fluid around the injector or level sensors
- Faulty temperature, level, or quality sensors within the tank
- P20E9 00 Fault Code – AdBlue/DEF Fluid Pressure: Drift Upwards
Common Faults and Diagnosis
Fault Code P20E9 00: AdBlue/DEF Fluid Pressure Drift Upwards
Fault code P20E9 00 indicates that the AdBlue (DEF) fluid pressure in the dosing system has risen above its specified range. This can be caused by a failing high-pressure pump, a blocked return line, contaminated fluid or a sensor that is no longer accurately reporting pressure levels to the ECU.
How the Pressure Drift Occurs
The Euro 6 SCR system relies on a finely tuned balance: AdBlue must be injected at a precise pressure to ensure complete reaction with NOₓ in the catalyst. If pressure drifts upwards—often due to a sticking check-valve or degraded pump seals—excessive fluid can be forced into the exhaust, leading to over-dosing, injector damage and crystallisation in the dosing module.
Symptoms and Operational Impact
When P20E9 00 is detected, the dashboard will display an “Emission Control Fault” message alongside the engine warning lamp. Initially, the vehicle may run normally, but persistent over-pressure triggers limp-home mode, reducing engine power and, eventually, invoking a mileage countdown. Once the countdown expires, the engine will refuse to restart until the fault is cleared.
Diagnosis and Recommended Action
A full diagnostic scan will confirm P20E9 00 and record related freeze-frame data. Technicians should inspect the high-pressure pump, return lines and pressure sensor for signs of blockage, wear or contamination.
Essex Recons Repair Services
At Essex Recons, we specialise in the reconditioning of Peugeot Partner and Citroën Berlingo AdBlue dosing units. We rebuild each AdBlue system to a high standard. Our service ensures your vehicle’s SCR system is restored quickly, keeping you on the road and compliant with Euro 6 emissions standards.
Part Numbers
9808625280, 9818531680, 9849387080, 9868018531, 9817601880, 16882619780, 1682615280
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Common Questions:
We at Essex Recons strive to exceed your expectations in the quality of our repairs. We aim to complete our repairs in a timely fashion while adhering to all ESD safety measures when working on sensitive equipment.
These units come with a lifetime* warranty.
To pay for the rebuild, simply click the product link(s) above to select the module you require. After that, place your order directly through our website. Once your order is complete, carefully package your unit inside a sturdy box with plenty of protective material. In addition, make sure you include your contact details and order number inside the box. Then, send your package to us using a tracked courier service. As soon as we receive your unit, we will test, rebuild, and return your module, complete with your warranty.
Yes! Once an order has been placed you can drop your unit off at the following address: Unit H, OYO Business Units, Hindmans Way, Dagenham, Essex, RM9 6LN, UK. Quote your order number at the till to ensure a smooth dropoff!