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P20E8 Powertrain

Reductant Pressure Too Low

Pressure in the AdBlue/DEF supply line is below the target. Usually a failing reductant pump, a clogged filter, frozen lines, or a leak in the pressurised circuit.

Affected components

  • Adblue pump
  • Adblue filter
  • Adblue lines

Common causes

  • High likelihood: Reductant pump weak or failed
  • Medium likelihood: Reductant filter clogged with crystals
  • Medium likelihood: Leak in pressurised reductant line

Possible symptoms

  • Check engine light or NOx warning on
  • AdBlue/DEF level or quality warning
  • Possible no-start countdown after ignore period
  • Failed emissions inspection (NOx)

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • This code can affect emissions
  • A drive cycle may be required after repair
  • Reduced-power or limp mode may occur

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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