Powertrain, generic (extended)

P20DC Exhaust Aftertreatment Fuel Supply Control Stuck Closed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The valve feeding the exhaust doser does not open when a regeneration starts, so the doser receives no fuel. A Hino patent shows how this is recognized: a pressure sensor between the shutoff valve and the dosing valve reads far below a threshold that depends on engine speed. Volvo and Mack list P20DC00 in AHI guide KC-2157 and tell technicians to look at the fuel supply first, then follow the guided diagnostics; a plugged fuel filter can mimic the fault. The electrical side is fine, which separates it from P20D7, P20D9 and P20DA. Stuck open is P20DB. Hino stores a stuck-closed fuel cut valve under P0005 instead.

Likely causes

Clogged fuel filter or water and dirt in the fuel
Supply valve seized shut
Internal fault in the dosing module

Symptoms

  • Check engine light on
  • Regenerations fail, soot load keeps rising
  • Reduced power in later stages

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,500
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

aftertreatment fuel supply solenoid

Related codes

P20DBP20D0P20D7P20DFP0005

References: static.nhtsa.gov, patents.google.com, law.cornell.edu.