P207F: Reductant Quality Performance
The AdBlue (DEF) quality is not within limits.
High risk
Many cars will block restarting after a countdown. Fix it soon.
Short answer · Can I keep driving with P207F?
Yes, for now, but follow the countdown. Many cars stop restarting once it ends. Have the fluid checked soon.
What does P207F mean?
Code P207F means the reductant (AdBlue/DEF) quality sensor or the NOx readings show the fluid is not effective. Diluted or old fluid is common.
AdBlue that is diluted, contaminated or very old does not reduce NOx enough. A faulty quality sensor can also set the code.
Fluid quality is checked with a refractometer: correct AdBlue has a urea content of 32.5 %. If the tank was filled with a wrong liquid, the whole system usually needs flushing and some parts may need replacing.
What the car does when the code is set
The AdBlue warning and check engine light come on. Many cars show a countdown in kilometres or starts; when it ends, the engine will not restart until the fault is fixed.
How the system works
Selective catalytic reduction (SCR) cuts nitrogen oxide emissions from diesel engines. A dosing unit sprays AdBlue (also called DEF, a 32.5 % urea solution in water) into the exhaust before a special catalyst, where it turns into ammonia and converts NOx into nitrogen and water. A quality sensor in the tank or the NOx sensors after the catalyst tell the engine control unit whether the fluid has the right concentration. If not, the system cannot meet emission limits and the law in many regions requires a warning and eventually a restart block.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Diluted or contaminated AdBlue (DEF)Water or other liquids in the tank.
- Old AdBlueAdBlue degrades with heat and age.
- Faulty quality sensorThe sensor in the tank fails.
- Dosing problemsA blocked injector reduces dosing so NOx stays high.
How it is diagnosed
- Check the fluidUse only fluid meeting ISO 22241. A workshop can measure the urea concentration.
- Drain and refill if contaminatedContaminated fluid must be removed, not diluted.
- Check the dosing systemTest the injector and pump.
- Check the countdownMany cars show how many starts or kilometres remain before a restart block.Never put fuel or water in the AdBlue tank. It can destroy the system.
Questions about P207F
Can I mix AdBlue brands?
Yes, as long as each meets ISO 22241. Never dilute it with water.
Will my car stop starting?
In many markets, after a warning period, the car will not restart until the fault is fixed. Follow the countdown shown on the dashboard.
Where can I buy AdBlue?
At most petrol stations, in bottles or at the pump. Buy fluid marked ISO 22241.