Common AdBlue Trouble Codes

See any of the codes below, give us a call for a permanent fix!

Our AdBlue, also known as diesel exhaust fluid (DEF), delete will be able to permanently resolve and fix any AdBlue related faults.

Most drivers will first notice an issue when seeing a warning on their instrument cluster panel. While it is not identical on all cars, Mercedes drivers for example, will often see light on accompanied by a message such as “engine start not possible” despite filling up the AdBlue tank. 

Further investigation will bring up a diagnostic trouble code (DTC). While there is not a single universal list of all AdBlue DTC’s, also known as fault codes, we have compiled a list of the the most common  that we have encountered and helped fix.

If your vehicle is showing any of the trouble codes below or even AdBlue fault codes which we are yet to encounter, please get in touch for a permanent fix.

Common fault codes:

  • P20E8 Reductant Pressure Too Low: DEF pump failure, clogged DEF filter, low DEF level.
  • P20E9 Reductant Pressure Too High: Blocked DEF injector, faulty DEF pressure sensor.
  • P20EE SCR NOx Catalyst Efficiency Below Threshold: SCR catalyst failure, poor quality DEF, NOx sensor fault.
  • P204F Reductant System Performance: DEF quality issues, DEF injection system problems, SCR catalyst issues.
  • P207F Reductant Quality Performance: Contaminated DEF, improper DEF concentration, sensor issues.
  • P203B Reductant Level Sensor Circuit Range/Performance: Faulty DEF level sensor, wiring issues, low DEF level.
  • P203C Reductant Level Sensor Circuit Low: DEF level sensor failure, wiring problems, low DEF level.
  • P203D Reductant Level Sensor Circuit High: DEF level sensor issues, wiring or connector problems.
  • P2047 Reductant Injection Air Pressure Sensor Circuit: Faulty air pressure sensor, wiring issues, air supply problems.
  • P2048 Reductant Injection Air Pressure Sensor Circuit Low: Sensor failure, wiring issues, air supply problems.
  • P2049 Reductant Injection Air Pressure Sensor Circuit High: Sensor failure, wiring issues, air supply problems.
  • P205B Reductant Tank Temperature Sensor Circuit Range/Performance: Faulty temperature sensor, wiring issues, sensor malfunction.
  • P205C Reductant Tank Temperature Sensor Circuit Low: Temperature sensor issues, wiring or connector problems.
  • P205D Reductant Tank Temperature Sensor Circuit High: Possible Causes: Sensor issues, wiring or connector problems.
  • P206A Reductant Quality Sensor Circuit: Faulty DEF quality sensor, wiring issues, contaminated DEF.
  • P206B Reductant Quality Sensor Circuit Range/Performance: DEF quality sensor failure, wiring or connector problems.
  • P206C Reductant Quality Sensor Circuit Low: DEF quality sensor issues, wiring or connector problems.
  • P206D Reductant Quality Sensor Circuit High: DEF quality sensor issues, wiring or connector problems.

Audi

Most Audi’s feature the codes under the most common codes listed above. Audi specific dashboard warnings can include: 

  • “AdBlue system malfunction” message with code: This could be a generic warning indicating various issues within the system.
  • “Refill AdBlue” light with code: This signifies low AdBlue fluid level.
  • Code PXXXX (specific code): This could point to a more specific problem like a faulty sensor, pump, or heating element within the AdBlue system.

Bentley:

Most Bentley’s feature the codes under the most common codes listed above. Bentley specific dashboard warnings can include: 

  • “AdBlue Warning Light” with a message: The message might specify a reason like “Refill AdBlue” or “AdBlue System Malfunction.”

BMW:

Most BMW’s feature the codes under the most common codes listed above. BMW specific dashboard warnings can include: 

  • “Engine Start Not Permitted (AdBlue Empty)” message: This signifies critically low AdBlue fluid level.
  • “AdBlue Fehlbefullung” message: This translates to “AdBlue Incorrect Filling” and could indicate using improper fluid in the AdBlue tank.

Citroen:

Most Citroen’s feature the codes under the most common codes listed above. Citroen specific dashboard warnings can include: 

  • “Defective AdBlue Level Sensor” message: This signifies a problem with the sensor that monitors the AdBlue fluid level.
  • “Refill AdBlue” light: This indicates low AdBlue fluid level.

Ford

Most Ford’s feature the codes under the most common codes listed above. Ford specific dashboard warnings can include: 

  • “AdBlue System Malfunction” message on the dashboard: This is a generic warning indicating a problem within the AdBlue system.
  • “AdBlue Warning Light” with a message: The message might specify a reason like “Refill AdBlue” or “Service AdBlue System.”

Land Rover

Most Land Rover’s feature the codes under the most common codes listed above. Land Rover specific dashboard warnings can include: 

  • “AdBlue Warning Light” with a message: The message might specify a reason like “Refill AdBlue” or “AdBlue System Fault.”
  • “AdBlue System Malfunction” message on the dashboard: This is a generic warning indicating a problem within the AdBlue system.
  • Code PXXXX (specific code): This could point to a more specific problem within the AdBlue system. Some codes you might encounter include:
    • P2000: Diesel Particulate Filter (DPF) problem (might be related to AdBlue system functionality)
    • P242F: AdBlue injection system malfunction
    • P2ADB: Incorrect DPF Fluid Level (DPF fluid is often referred to as AdBlue in some resources)

Mercedes-Benz:

Most Mercedes feature the codes under the most common codes listed above. Mercedes specific dashboard warnings can include: 

  • P13DF AdBlue Reductant Metering Unit Malfunction: Faulty reductant metering unit, wiring issues, connector problems.
  • P13E0 AdBlue System Malfunction – Check Component N118/5 (Pressure Line Heater 1): Faulty pressure line heater, wiring issues, heater malfunction.
  • P13E1 AdBlue System Malfunction – Check Component N118/5 (Pressure Line Heater 2): Faulty pressure line heater, wiring issues, heater malfunction.
  • P13E2 AdBlue System Malfunction – Check Component N118/5 (Return Line Heater): Faulty return line heater, wiring issues, heater malfunction.
  • P13E3 AdBlue System Malfunction – Check Component N118/5 (Heater Circuit): Faulty heater circuit, wiring issues, connector problems.
  • P13E4 AdBlue System Malfunction – Check Component N118/5 (Reductant Pump): Faulty reductant pump, wiring issues, connector problems.
  • P13E5 AdBlue System Malfunction – Check Component N118/5 (Reductant Injector): Faulty reductant injector, wiring issues, injector malfunction.
  • P13E6 AdBlue System Malfunction – Check Component N118/5 (Temperature Sensor): Faulty temperature sensor, wiring issues, sensor malfunction.

Volkswagen

Most VW’s feature the codes under the most common codes listed above. VW specific dashboard warnings can include: 

  • “AdBlue System Malfunction” message: This is a generic warning indicating a problem within the system.
  • A red recharge AdBlue light: This means you should stop the car as soon as it’s safe: A restart will not possible without refilling the AdBlue system.