P20EE on Peugeot: How to Diagnose & Fix
SCR NOx Catalyst Efficiency Below Threshold
2 Peugeot models · 2 documented issues · 2 critical · $300-$1,800 repair
P20EE on Peugeot by model: symptoms, diagnosis and fix
The AdBlue (SCR) system on BlueHDi engines triggers fault warnings and countdown timers to engine disable. The AdBlue tank/pump module (supplied as one unit) is the most common failure point, with the NOx sensor and AdBlue injector, often clogged by crystallized fluid, also failing.
Common Symptoms
- AdBlue warning light
- Engine start countdown
- NOx sensor fault
- Reduced power
How to Fix
Replace the failed part, most often the AdBlue tank/pump module (supplied as one unit) or the NOx sensor, and clean the AdBlue injector. Flush the AdBlue tank if crystallization is present. Reset the SCR system counters with diagnostic equipment.
Sources for this issue (2)
BlueHDi diesel 208s suffer chronic AdBlue (SCR) system failures: the urea injection pump and its control electronics are integrated into the AdBlue tank, and pump seizure, urea crystallisation, faulty level sensors and (on pre-2018 cars) a non-vented filler cap that pulls a vacuum in the tank all kill urea delivery. The ECU then logs faults such as P20E8 (reductant pressure too low) or P20EE, lights the UREA/engine warning and starts a countdown (typically 1,100 km) after which the engine is prevented from starting. Peugeot's official fix is a complete new AdBlue tank assembly with ECU coding, quoted around GBP 1,100-1,300 at UK dealers.
Common Symptoms
- UREA or AdBlue warning light with 'Engine fault: Repair needed' message
- Start-prevention countdown in km shown on the dash
- AdBlue level reads empty or incorrect despite being filled
- Engine refuses to start once the countdown reaches zero
- Repeated NOx sensor or anti-pollution faults that return after replacement
How to Fix
Diagnose which SCR component failed — NOx sensors and the AdBlue injector should be checked first, but a dead in-tank pump means a replacement AdBlue tank assembly that must be coded and primed to the car. Independent specialists and aftermarket repair kits can substantially undercut dealer pricing; do not ignore the countdown, as the car will refuse to restart at zero.
Sources for this issue (4)
- Adblue tank replacing and updating the ECU to accept the new tank and electrical components | Peugeot 208 Forums (208ownersclub)forum
- Peugeot & Citroen AdBlue failure fix (lists 208; P20E8/P20EE, urea light, countdown) — Torx Tuningarticle
- Peugeot AdBlue Fault Fixed (208 BlueHDi listed; P20E8, pump/PCB failure, non-start) — Fastlane Performancearticle
- AdBlue: l'UFC-Que Choisir saisit la DGCCRF et la Commission europeenne (Peugeot/Citroen most affected, 1,731 testimonies, ~EUR 1,000 avg repair)article
P20EE code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P20EE mean on a Peugeot?
P20EE stands for "SCR NOx Catalyst Efficiency Below Threshold." This is a diesel emissions code meaning the Selective Catalytic Reduction (SCR) catalyst on Bank 1 is not cleaning up exhaust as well as it should. The SCR system sprays Diesel Exhaust Fluid (DEF) into the hot exhaust to convert harmful nitrogen oxides (NOx) into harmless nitrogen and water; NOx sensors before and after the catalyst tell the computer how well it is working. When the measured efficiency falls below the required threshold, this code sets. Because it is an emissions-protection code, it often triggers warning lights and can lead to reduced power or a speed limit (a 'derate') if left unfixed. On Peugeot it is documented across 2 models: 308, 208.
What are the most common causes of P20EE?
The most common causes of P20EE are: Poor quality, contaminated, or wrong DEF fluid, Faulty or clogged DEF injector/dosing valve, Failed upstream or downstream NOx sensor, Degraded or failed SCR catalyst, Exhaust gas temperature sensor fault affecting dosing, Exhaust or DEF line leak, DEF line/heater problems (crystallization or freezing). The specific cause varies by vehicle.
How much does it cost to fix P20EE on a Peugeot?
Published repair estimates on Peugeot range from $300 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.