P00CA

Code

Generic P — Powertrain

Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 65 RU: 24

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Causes

Short to battery voltage on the regulator solenoid control/supply wire
Corroded, bent or pushed-out connector terminal at solenoid or PCM
Damaged, chafed or pinched wiring harness causing voltage feedback
Faulty fuel pressure regulator solenoid (internal short)
Poor or missing ground at PCM or related ground strap
Blown fuse or failed relay supplying the circuit

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Stored P00CA (or manufacturer specific) DTC
Poor idle, stalling, hesitation or reduced drivability
Hard start or extended crank
Fuel rail pressure abnormal (too high or unstable) or fuel trim abnormalities
Reduced fuel economy or limp-home mode on some vehicles

What to check

Retrieve freeze frame and live data: commanded regulator duty, fuel rail pressure, and related sensors.
Visual inspection of solenoid connector and wiring for damage, corrosion, or pushed-out pins.
Check fuses and relays for the fuel system circuit.
Backprobe solenoid connector with ignition ON (engine OFF) to confirm supply voltage presence and expected level.
Measure control wire voltage with engine running to observe PCM command (may be PWM).
Measure resistance of the solenoid coil (with connector disconnected) and compare to manufacturer spec.

Signal parameters

Supply (battery) voltage at connector with key ON: approximately battery voltage (11–14 V).
Control output when commanded ON (depending on design): PCM often grounds the solenoid — low voltage near 0–1 V when active; open/inactive near battery voltage.
If PCM uses PWM control: typical frequency range commonly 20–200 Hz (varies by manufacturer).
Solenoid coil resistance: typically a few ohms to a few tens of ohms — consult vehicle-specific service data for exact value.
Abnormal condition: control circuit reads close to battery voltage when it should be low (indicates short to power or PCM not switching).

Diagnostic algorithm

Read and record all stored DTCs and freeze frame data. Note fuel rail pressure and commanded regulator duty or state.
Clear codes. Attempt to reproduce the code to ensure it returns and confirm intermittent vs. permanent.
Perform a careful visual inspection of the fuel pressure regulator solenoid, connector, and wiring (follow harness from solenoid to PCM). Repair or secure any damaged insulation or wiring.
With ignition ON (engine OFF), backprobe the connector: verify constant supply voltage where expected and check the control terminal voltage. Verify values match expected basics (battery voltage on supply; control near battery or ground depending on design).
Start engine (if safe) and monitor control signal. Use a DVOM or oscilloscope to observe if control is PWM and whether voltage swings/duty are expected. Look for abnormally high steady voltage on the control line.
Disconnect the solenoid connector and measure resistance of the solenoid coil on the bench. Compare to spec; a shorted coil (very low resistance) suggests a bad solenoid.
Check continuity between the control wire and battery positive to detect a short to power. Check continuity between control wire and PCM pin to verify harness integrity. Repair any short/open found.
If wiring and solenoid test good, verify PCM output with scope or substitute known-good PCM if available and appropriate. Consult manufacturer procedures before replacing PCM.
After repair or component replacement, clear codes and perform a road test to verify the fault does not return and fuel pressure/delivery and drivability are normal.