Damaged, chafed or broken wiring in the regulator solenoid supply or control circuit; Corroded, loose or pushed-out pins in the solenoid or control unit connector; Faulty fuel pressure regulator solenoid with an open internal winding; Blown fuse or faulty relay feeding the regulator circuit, where fitted; Low or unstable battery or charging system voltage affecting the supply; Internal driver fault in the engine control unit.

P00C8

Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit/Open.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
C8: FaultThe specific fault in that area

What it means

P00C8 is a generic powertrain code meaning the engine control unit has detected an open circuit in the supply voltage control circuit for fuel pressure regulator A solenoid. The control unit monitors the circuit that powers or switches the regulator solenoid and sets the code when it sees no current flow or a voltage that does not match what it commanded. Exact circuit layout and which component is 'A' depend on the vehicle and engine.

Symptoms

Engine warning light on
Hard starting or long cranking
Rough idle or misfire under load
Loss of power or limp mode
Engine stalling or cutting out
Poor fuel economy

Possible causes

Damaged, chafed or broken wiring in the regulator solenoid supply or control circuitlikely
Corroded, loose or pushed-out pins in the solenoid or control unit connectorlikely
Faulty fuel pressure regulator solenoid with an open internal windinglikely
Blown fuse or faulty relay feeding the regulator circuit, where fittedpossible
Low or unstable battery or charging system voltage affecting the supplypossible
Internal driver fault in the engine control unitrare

How to diagnose

Read all stored codes and freeze frame data, noting engine speed, load, temperature and voltage when the fault set, and check for related fuel pressure codes.
Check battery condition and charging voltage, as low voltage can cause supply faults.
Visually inspect the regulator solenoid wiring and connector for chafing, heat damage, corrosion, water ingress and bent or loose pins.
Check the relevant fuses and relays against the wiring diagram for the specific model and engine.
With the ignition on, test for supply voltage and a good earth or control signal at the solenoid connector, following the manufacturer's procedure.
Perform a continuity and resistance check of the wiring between the solenoid and the control unit, with the connectors disconnected and the power off.
Measure the solenoid winding resistance and compare with the specification for the vehicle.
Use a scan tool's active test, if supported, to command the regulator and watch for a response in fuel pressure data.

How to fix

Repair or replace damaged wiring, ensuring proper joins and routing away from heat and abrasion.
Clean, repair or replace corroded or damaged connector terminals and secure the connector fully.
Replace the fuel pressure regulator solenoid or the assembly it belongs to if its winding is open or out of specification.
Replace the blown fuse or faulty relay after finding out why it failed.
Repair the battery or charging fault if voltage is found to be low or unstable.
Replace or repair the engine control unit only after the wiring and solenoid are proven good and the driver fault is confirmed.

Can I keep driving?

Medium severity

The car may run, but fuel pressure control could be wrong, leading to poor running, stalling or limp mode. Have it checked soon and avoid long journeys or heavy loads until fixed.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.