P00C8

Code

Generic P — Powertrain

Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 27 EN: 57 RU: 49

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Page language: EN

Causes

Open or high-resistance wiring in solenoid supply or control circuit
Corroded, loose or damaged connector at solenoid or wiring harness
Failed fuel pressure regulator solenoid coil
Blown fuse or faulty power/ignition relay supplying the circuit
Short to voltage or ground in the control wiring
PCM/output driver fault or poor PCM ground

Symptoms

Check Engine Light (MIL) illuminated
Hard starting, extended crank time or no start in severe cases
Reduced engine power or limp-home mode
Erratic idle, stalling or stumbling
Poor fuel economy
Fuel rail pressure out of expected range (high or low)

What to check

Read stored DTCs and freeze frame/fuel rail pressure data with a scan tool
Visually inspect wiring and connector at fuel pressure regulator/solenoid and fuel module for damage, corrosion, contamination or loose terminals
Check fuses and relays for the fuel system/powertrain circuits
Back-probe the solenoid connector with key ON (engine OFF) to verify battery supply and control signal
Measure solenoid coil resistance with ohmmeter (engine off, connector disconnected)
With engine running, check for PWM or switching at control circuit using a scope or multimeter capable of duty-cycle/readout

Signal parameters

Supply voltage (key ON, engine OFF): battery voltage (~11.5–14.5 V) present at the solenoid power pin
Control output: PCM ground-switch or PWM from 0–14 V; duty cycle 0–100% depending on commanded pressure
Expected coil resistance (typical range): roughly 5–40 ohms (manufacturer-specific — compare to spec)
When commanded ON, control circuit should pull to near 0 V (ground) or show PWM signal; when OFF, control circuit should be near battery voltage (if power-side switching) or open/high

Diagnostic algorithm

Retrieve DTC P00C8 and any related codes; note freeze-frame data and fuel rail pressure values.
Visually inspect connector and wiring at Fuel Pressure Regulator A and fuel pump module; repair visible damage and ensure good pin contact.
Verify applicable fuses and relays; replace if faulty.
With ignition ON (engine OFF) back-probe the connector: verify battery supply at the power pin and check the control pin voltage.
Disconnect connector and measure solenoid coil resistance; compare to manufacturer spec. An open/infinite resistance indicates a failed solenoid.
Start engine and monitor control waveform at the control pin with an oscilloscope or a scan tool capable of reading PWM/duty cycle. Confirm PCM is commanding the solenoid.
Perform a wiggle test on wiring while monitoring live data and voltage for intermittent faults.
If wiring and connector are good but solenoid fails or is out of spec, replace the fuel pressure regulator solenoid or assembly. Follow safe procedures: relieve fuel system pressure before disconnecting fuel components and clean area to avoid contamination.
If new solenoid and wiring are good but code persists, inspect PCM grounds and harness at PCM; test/replace PCM only after confirming wiring and actuators are good.
Clear codes and road-test to confirm repair; re-scan to ensure code does not return.

Likely causes

Broken or chafed wire to the regulator solenoid connector
Corroded terminal at the solenoid connector or in the fuel pump module harness
Failed solenoid coil (open circuit)
Blown fuse or defective relay supplying the solenoid
PCM driver stuck open or internally damaged

Fault status

⚠️ Status

Powertrain control module reports an open or abnormal voltage condition in the Fuel Pressure Regulator A solenoid supply/control circuit (no supply, open, or unexpected voltage), potentially causing incorrect fuel rail pressure.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-2 hours