What it means
Voltage on the fuel pressure regulator D control line is below the expected window. Wire shorted to ground or coil short.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Fuel pressure regulator D uses an electrically controlled solenoid to help regulate fuel pressure. The control module monitors voltage on its control circuit; P2C03 sets when the circuit voltage is detected below the expected range, such as from a short to ground or a shorted coil.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in regulator coil
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
How to diagnose it
- Review freeze-frame and live fuel-pressure data to see when the low circuit reading occurred and whether pressure control was affected.
- With the ignition off as specified by the manufacturer, inspect regulator D’s connector and harness for corrosion, damaged insulation, or contact with ground.
- Check the connector pins for corrosion or poor contact that could lower the circuit reading.
- Use the wiring diagram to test the regulator D control wire for a short to ground and check its continuity with the circuit powered down.
- If wiring and terminals are sound, test regulator D’s coil for an internal short using the manufacturer’s procedure and specification.
Common fixes
- Clean or repair corroded regulator D connector terminals.
- Repair the control wire shorted to ground.
- Replace regulator D if its coil is internally shorted and the harness is sound.
Can I keep driving?
Hard starting, stalling, or power loss may occur, especially under load; avoid high-speed or high-load driving and stop if the engine stalls. Continued driving can leave the vehicle unable to maintain fuel pressure or restart.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.