P204F: Reductant (AdBlue) system performance (bank 1)
The AdBlue system is not dosing as it should, so nitrogen oxide reduction is not as expected. Usually the injector, the pump or the lines.
| Code | P204F |
|---|---|
| System | Engine and transmission |
| Group | P20xx, Emissions: catalysts and AdBlue |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P204F means
The AdBlue system pumps fluid from its tank and sprays it into the exhaust through an injector so the SCR catalyst can remove nitrogen oxides. The ECU has found that the system is underperforming: it cannot reach the requested pressure or quantity, or the NOx sensors do not show the expected result.
Most common causes
- Low AdBlue level or poor quality AdBlue
- AdBlue injector blocked with urea crystals
- Worn AdBlue pump or blocked pump filter
- AdBlue lines blocked, kinked or leaking
- NOx sensor or AdBlue pressure sensor reading wrongly
Symptoms
- Engine warning light on
- AdBlue or emissions warning on the dashboard
- Possible countdown before the engine is prevented from starting
- White crystal deposits near the injector or exhaust
Can you drive with P204F?
With care You can drive, but get to a garage soon. On many cars, if the fault persists, a dashboard message counts down the distance left before the engine will not restart.
Open the bonnetthe in-depth explanation
How to check it
First check the AdBlue level and top up if needed with fluid that meets ISO 22241. If you can see white crusty deposits around the injector on the exhaust, tell the garage: it points to a blocked or leaking injector.
How to read and clear P204F with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P204F with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P204B The AdBlue pressure sensor gives readings outside the normal range
- P204C The AdBlue pressure sensor gives a lower signal than normal
- P204D The AdBlue pressure sensor gives a higher signal than normal
- P204E The AdBlue pressure sensor fails now and then
- P2050 The AdBlue injector 1 on bank 2 has an open circuit
- P2051 The circuit signal of AdBlue injector 1 on bank 2 is low
- P2052 The circuit signal of AdBlue injector 1 on bank 2 is high
- P2053 The AdBlue injector 2 on bank 1 has an open circuit
- P2002 Diesel particulate filter efficiency below threshold (bank 1)
- P2003 Diesel particulate filter efficiency below threshold (bank 2)
- P2004 Intake manifold runner control stuck open (bank 1)
- P2005 Intake manifold runner control stuck open (bank 2)
What does code P204F mean?
The AdBlue system pumps fluid from its tank and sprays it into the exhaust through an injector so the SCR catalyst can remove nitrogen oxides. The ECU has found that the system is underperforming: it cannot reach the requested pressure or quantity, or the NOx sensors do not show the expected result.
Can you drive with P204F?
You can drive, but get to a garage soon. On many cars, if the fault persists, a dashboard message counts down the distance left before the engine will not restart.
How do you clear P204F?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P204F comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
