P00C9
Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit Low
Supply voltage to fuel pressure regulator A solenoid below expected range — fuse, relay or wiring fault.
- 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.
- Supply fuse blown or relay failedCommon
- Connector pins corroded - high contact resistanceLess likely
- Harness chafing through insulationLess likely
Parts involved
- Regulator Supply
- Fuse
- Relay
P00C9 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.