P00CA
Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit High.
- 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
- CA
- FaultThe specific fault in that area
What it means
P00CA means the engine control unit has detected a high voltage on the supply voltage control circuit for fuel pressure regulator 'A' solenoid. The control unit monitors this circuit and sets the code when the voltage is higher than expected for the commanded state. This is often caused by a short to voltage in the wiring, a fault in the regulator solenoid, or an internal driver fault in the control unit. The exact layout depends on the engine and fuel system, so check the model-specific wiring diagram.
Symptoms
- Engine warning light on
- Reduced power or limp mode
- Hard starting or long cranking
- Rough running, hesitation or misfires under load
- Engine stalling or cutting out
- Fuel pressure fault codes stored alongside P00CA
Possible causes
- Wiring on the regulator solenoid supply or control circuit shorted to a voltage source, or chafed against other live wiringlikely
- Faulty fuel pressure regulator solenoid with an internal fault or incorrect resistancelikely
- Corroded, damaged or loose connector terminals at the regulator or control unitpossible
- Fault in the relay, fuse or power supply feeding the regulator circuit, where fittedpossible
- Fault in the engine control unit driver circuitrare
- Outdated control unit software, only where the manufacturer has issued a bulletin for this coderare
How to diagnose
- Read all stored codes and freeze frame data, noting engine load, speed and battery voltage when the code set, and check for other fuel pressure or supply voltage codes.
- Check the battery and charging voltage, as abnormal system voltage can upset circuit monitoring.
- Visually inspect the regulator solenoid wiring and connector for chafing, heat damage, water ingress, bent pins and corrosion.
- Check the related fuses and relay, if fitted, against the wiring diagram for the model and engine.
- With the ignition off, measure the solenoid coil resistance and compare it with the manufacturer's specification.
- Back-probe the circuit with the connector plugged in and unplugged to check for voltage where there should be none, and check for shorts to power and to adjacent circuits.
- Use a scan tool's live data or actuator tests, if supported, to compare commanded and actual fuel pressure.
- If the wiring and solenoid test good, check the control unit's power and ground supplies and then the control unit output, following the manufacturer's procedure.
How to fix
- Repair or replace damaged wiring, and secure it clear of live wires and hot or moving parts.
- Clean, repair or replace faulty connectors and terminals.
- Replace the fuel pressure regulator solenoid or the assembly it is part of if it tests out of specification.
- Replace faulty fuses or relays after finding out why they failed.
- Replace or repair the engine control unit only after the wiring and solenoid have been proven good, and make sure it is correctly programmed.
- Update the control unit software only if a manufacturer bulletin names it as the fix for this fault.
Can I keep driving?
The car may run in a reduced power mode and could stall or become hard to start if fuel pressure is not controlled correctly, so get it checked soon. Avoid long journeys and stop driving if power loss or stalling occurs, as that is a safety risk in traffic.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.