P20E8
PPowertrainReductant (AdBlue) Pressure Too Low
What does this code mean?
Severity : MediumP20E8 indicates that reductant pressure, the AdBlue/DEF supply pressure, is too low. The ECU monitors pressure in the line between the pump and the AdBlue injector and finds that it does not reach the requested value. Without enough pressure, AdBlue cannot be dosed correctly into the exhaust.
Symptoms
- AdBlue or check engine light on.
- Warning message with a countdown before engine start is restricted.
- Higher NOx emissions.
- Possible power reduction depending on the vehicle.
Possible causes
- AdBlue level too low in the tank.
- Frozen or crystallised AdBlue in the lines.
- Faulty AdBlue pump or clogged pump filter.
- Leak at a line or fitting in the system.
- Faulty AdBlue pressure sensor.
Diagnosis and repair
- Check AdBlue level and quality.
- Look for leaks or white crystal deposits along the system.
- Read commanded and actual pressure in live data.
- Test the pump with a diagnostic tool, replace the filter or pump if needed.
- Clear the code and road test.
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Code
P20E8
Category
Powertrain
Prefix
P
Standard
OBD-II / SAE J2012