Powertrain, generic (extended)

P20DF Exhaust Aftertreatment Fuel Pressure Sensor Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The signal of the doser feed pressure sensor sits below its lower limit. Electrically that suggests a grounded signal line or a missing reference voltage. Hino describes its P20DF as the line pressure sensor reading too low and shows that real pressure loss can trigger it too: a fuel cut valve that hangs, or dirty fuel restricting the filter ahead of the dosing injector. Hino also changed the detection threshold by software on 2013–2016 cab-over trucks and corrected the measuring point in its workshop manual. So the check should cover both the sensor circuit and the fuel supply. High signal is P20E0, the generic circuit fault P20DD.

Likely causes

Real low pressure from a restricted filter or contaminated fuel
Signal wire shorted to ground or reference voltage lost
Fuel cut valve sticking
Outdated detection threshold, fixed by a software update

Symptoms

  • Check engine light on
  • Regeneration blocked

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–800
Time0.5–2.5 h

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

Parts involved

aftertreatment fuel pressure sensor

Related codes

P20DDP20DEP20E0P20E1P20DC

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.