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

P0003 Fuel Volume Regulator A Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The fuel volume regulator (also called metering unit or suction control valve) is a solenoid valve on the inlet side of the high-pressure pump, used mainly on common-rail diesel engines. The engine control module pulses it to set how much fuel the pump draws in and delivers to the rail, and in this way controls rail pressure. P0003 means the control module measures a voltage or current below the expected range on the control circuit, typically because of a short to ground. On some output stages an open circuit is also reported as low. A short on the switched ground side can keep the valve permanently energised.

Likely causes

Harness chafed through, short to ground
Shorted turns in the regulator coil (resistance too low)
Water or corrosion in the connector
Output driver in the engine control module faulty

Symptoms

  • Check engine light on
  • Hard starting or stalling
  • Loss of power or limp mode
  • Low rail pressure code possible

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–2,500
Time0.5–3 h

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

Parts involved

fuel volume regulatorhigh pressure fuel pumpfuel volume regulator wiring

Related codes

P0001P0002P0004P2372P0087

References: law.cornell.edu, bosch-mobility.com, denso-am.eu.