P2C04
Fuel Pressure Regulator D Control Circuit High
Voltage on the fuel pressure regulator D control line is above the expected window. Wire shorted to B+ or coil open.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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
Common causes
Ordered by how often each turns out to be the cause.
- Control wire shorted to B+Common
- Open regulator coilPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Fuel Pressure Regulator D
- Wiring Harness
- Fuel Rail
P2C04 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.