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DTC codes / P2Cxx · Hybrid propulsion / P2C03

P2C03Fuel Pressure Regulator D Control Circuit Low

P2C03 indicates that the powertrain control module has detected a low-voltage condition on the control circuit for the fuel pressure regulator labeled D, which is a solenoid or actuator used to manage fuel pressure. The circuit is considered low when the voltage falls below the expected range, often due to a short to ground, an open circuit, or a faulty regulator.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Rough idle or stumbling during acceleration due to incorrect fuel pressure
  • Reduced engine power or limp mode in some vehicles
  • Poor fuel economy or rich/lean fuel mixture codes
  • Hard starting or extended cranking times

Common causes, most likely first

  1. Faulty fuel pressure regulator D solenoid or actuator
  2. Damaged or corroded wiring in the control circuit (short to ground or open)
  3. Loose or corroded electrical connector at the regulator
  4. Failed powertrain control module driver for the circuit
  5. Blown fuse or relay supplying power to the regulator circuit

How to diagnose and fix it

  1. Inspect the wiring harness and connector at the fuel pressure regulator for damage, corrosion, or looseness
  2. Check the fuse and relay that supply power to the regulator circuit
  3. Measure resistance of the regulator solenoid and compare to manufacturer specifications
  4. Test the control circuit for a short to ground or open using a multimeter and wiring diagram
  5. If the circuit is intact, substitute a known-good regulator to see if the code clears
  6. Repair or replace damaged wiring or connectors as needed
  7. Clear the code and verify the repair with a test drive

Don't overlook the wiring harness

  • A common cause of P2C03 is a chafed wire in the harness near the fuel pressure regulator, which can short to ground intermittently and set the code only under certain conditions.
  • The code does not always mean the regulator itself has failed; the control circuit can be affected by a faulty ground connection elsewhere on the engine.
  • Some vehicles use a fuel pressure control module that can fail and cause this code, even though the regulator is functioning correctly.
  • A low voltage code can be set by a weak battery or charging system issue, so always check battery voltage and connections before replacing parts.

Can I keep driving with P2C03?

You can usually drive with this code, but avoid heavy acceleration or towing until it is repaired, as incorrect fuel pressure may cause poor performance or increased emissions.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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