How is fault code P20EE fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Top up the AdBlue tank to full, this clears a meaningful percentage of P20EE codes if the tank was just low 2. Check live data on AdBlue dosing rate and NOx sensor readings 3. If it's winter and the car has been parked outside for days, the AdBlue may be frozen, the heater should clear it once the engine warms up 4. Inspect the AdBlue tank for contamination, if anything other than clear, slightly straw-coloured fluid, drain and refill 5. Check for software updates with the dealer, several manufacturers have published TSBs for this code specifically 6. If everything else is clean, the dosing pump or NOx sensor is the next suspect, both workshop diagnostics

SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1

Jump to the fix

Severity

Low

Can I keep driving?

Usually drivable; have it fixed at the first opportunity.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Top up the AdBlue tank to full, this clears a meaningful percentage of P20EE codes if the tank was just low 2. Check live data on AdBlue dosing rate and NOx sensor readings 3.

PPowertrain
2Generic code
0Fuel / Air
EESequence number

What does it mean?

P20EE is a Powertrain (engine, transmission, fuel system) fault code. It indicates: SCR NOx Catalyst Efficiency Below Threshold Bank 1 . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

Symptoms

Likely causes

How to fix it

Codes From the Same System

All Fault Codes

Related Similar Codes

This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.