Powertrain, generic (extended)

P20D0 Exhaust Aftertreatment Fuel Injector A Stuck Closed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The exhaust fuel doser is commanded to inject but no fuel gets through, typically because the nozzle tip is plugged. Detection usually relies on line pressure that fails to drop or on too little heat build-up across the oxidation catalyst. Volvo and Mack list P20D0 in their AHI troubleshooting guide KC-2157; the suggested steps are checking the AHI module and fitting a new nozzle after flushing both supply tubes, and the nozzle there is a maintenance part due at 150,000 miles. CARB demands a fault whenever the injection system can no longer reach regeneration. Without dosing the filter keeps filling with soot. Stuck open is P20CF.

Likely causes

Nozzle tip clogged with carbon
Dosing module or supply valve not passing fuel
Kinked or blocked fuel line to the nozzle

Symptoms

  • Check engine light on
  • Regenerations fail or are requested constantly
  • Soot warning and reduced power

Repair estimate

DifficultyHardWorkshop job
Parts and labour€200–1,500
Time1–3 h

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

Parts involved

aftertreatment fuel injector

Related codes

P20CFP20CCP20DCP20D6P24F7P2463

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.