Code Definition

P0004 — Fuel Volume Regulator Control Circuit High

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0004

P0004 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0004 is stored, the module has detected a signal or supply voltage higher than the expected operating range.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0004 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The Fuel Volume Regulator, also called the Fuel Metering Valve or MPROP on Bosch CP3 and CP4 common rail systems, is a Pulse Width Modulated solenoid mounted on the high pressure pump that meters low pressure fuel into the pumping chambers and therefore controls common rail pressure. The Engine Control Module commands the regulator through a high side or low side driver and monitors the control leg voltage to confirm that the commanded state is actually being reached. DTC P0004 is set when the ECM sees the control circuit voltage stuck too high for the commanded duty cycle, which typically ind...

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