What These Codes Mean

Both codes relate to the Selective Catalytic Reduction (SCR) system used to reduce NOx emissions. However, their root causes differ:

• P207F – Reductant Quality Performance: Indicates the ECU has detected poor-quality AdBlue or dosing inconsistency.
• P20EE – SCR NOx Catalyst Efficiency Below Threshold: The SCR catalyst isn’t converting enough NOx, often due to sensor or dosing errors.

In simple terms: P207F blames the fluid, while P20EE blames the system.

Vehicles Commonly Affected

We regularly see these codes on Ford Transit, Mercedes Sprinter, Peugeot Boxer, and Citroën Relay vans—especially those used for short stop-start driving. They’re also common across JLR Ingenium and VW Crafter models using Bosch SCR systems.

Shared Symptoms

• “AdBlue Quality Poor” message or No Start in 500 miles countdown
• Increased AdBlue consumption
• Stored P207F and P20EE together in ECU memory
• Reduced performance or restricted engine torque
• NOx sensor voltage out of range

How P207F Develops

The P207F code means the ECU believes the AdBlue quality is outside the expected range. That can happen when:

• AdBlue has aged or been contaminated with fuel or water
• Temperature or pressure sensors read incorrectly
• The dosing module misfires due to crystallisation in the injector line
• Aftermarket fluid with low urea concentration has been used

In reality, P207F often appears after low battery voltage, jump-starts, or winter freezing—when sensors temporarily lose calibration.

How P20EE Develops

The P20EE code is different. It means the SCR catalyst isn’t reducing NOx levels enough. Common causes include:

• Failed or aged NOx sensor before or after the catalyst
• Blocked injector or dosing malfunction
• Catalyst contamination from engine oil or fuel vapour
• Faulty AdBlue pump pressure regulation

Because the system measures NOx conversion efficiency, a single bad reading from one sensor can trigger P20EE even if the catalyst itself is fine.

Which Code Should You Fix First?

When both appear, always start with P207F. If the system thinks fluid quality is poor, it automatically reduces dosing, which in turn causes the SCR efficiency (P20EE) to drop. Fixing the first code often clears the second automatically.

You can confirm this using live data from a professional diagnostic tool—look for NOx conversion rate (%) and reductant quality readings.

How We Fix P207F & P20EE On-Site

At AdBlue Specialist, we handle both codes through full SCR testing and, where appropriate, software recalibration. Our mobile process includes:

• Checking live NOx readings with both sensors
• Verifying dosing pump pressure and duty cycle
• Performing an AdBlue reset or delete where permitted
• Inspecting the NOx sensor circuit for voltage drift
• Reviewing SCR dosing maps to identify derate triggers

Because we work entirely through the OBD port, there’s no cutting or drilling—just safe, reversible software editing that restores proper dosing control.

How Long Does It Take to Fix?

Most P207F and P20EE faults are diagnosed and cleared in under an hour. Severe crystallisation or failed sensors may require part replacement, but our tools confirm root cause before any component is ordered—saving you money and guesswork.

Real-World Example

Last month, a Peugeot Boxer 2.0 BlueHDi arrived showing both codes. Fluid quality tested fine, but the upstream NOx sensor read 0.1V static. After replacing the sensor and recalibrating the SCR map, both P207F and P20EE cleared—and the countdown disappeared instantly.

Related Faults to Watch

• P20EE – Peugeot SCR Efficiency Fault
• P207F – Ford Transit AdBlue Quality Performance Fix
• NOx Sensor Delete & Bypass Guide
• Mobile AdBlue Removal Stoke-on-Trent

Can You Keep Driving?

Yes, but not for long. Once the system logs both codes, the ECU starts a 500–700 mile countdown to engine lockout. Leaving the fault active can also damage the SCR catalyst due to unburned dosing fluid. It’s best to get it checked as soon as possible.

Prevention Tips

• Use high-quality AdBlue from sealed 10L containers.
• Keep the cap tight to prevent contamination.
• Run the vehicle long enough for the SCR system to heat up fully.
• Have the AdBlue system checked annually, especially before winter.

Mobile Help Wherever You Are

We offer mobile AdBlue repair across Stafford, Crewe, and Newcastle-under-Lyme. No towing, no long waits — we come to you and fix P207F or P20EE faults on-site.

When a Reset Isn’t Enough

In some cases, an AdBlue reset clears the codes temporarily but they come back after a few miles. That usually means the root cause — like a failing NOx sensor or poor dosing rate — hasn’t been fixed. Our software approach checks these values live before applying any reset, ensuring the problem is truly solved.

Need a Same-Day Fix?

If your dashboard shows P207F or P20EE, don’t wait for the countdown to reach zero. Call our mobile team for fast diagnosis and a permanent fix. We’ll get your SCR system back online safely.