Powertrain, generic · Fuel and air metering, auxiliary emission controls

P009E Fuel Pressure Relief Control Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The fuel pressure relief control is an electrically controlled valve on the fuel rail that the engine control module opens to reduce rail pressure deliberately, for example on overrun, on load drops or when the engine is switched off. It differs from the purely mechanical pressure relief valve, which opens passively at overpressure, and from the pressure regulator, which controls pressure continuously. Manufacturer documents show this code mainly on heavy-duty diesel engines. P009E means that rail pressure does not drop as expected when the valve is commanded open, i.e. the valve does not open or opens too little. On some trucks the manufacturer has corrected false detections by a software update, so other fuel codes and real symptoms should be checked first.

Likely causes

False detection by engine control software (updates exist for some trucks)
Valve sticking closed, e.g. from contamination
Rail pressure sensor inaccurate

Symptoms

  • Check engine light on
  • Reduced power possible
  • Sometimes no further symptoms

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–900
Time0.5–4 h

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

Parts involved

fuel pressure relief control valvefuel pressure relief valve wiringfuel rail

Related codes

P009FP009BP0088P0089P000F

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