Short to voltage on the supply control circuit wiring; Open or high-resistance connection in the solenoid supply circuit; Failed fuel pressure regulator solenoid; Corroded or damaged electrical connector at the solenoid; Faulty powertrain control module (PCM) driver circuit; Blown fuse or relay supplying power to the solenoid circuit

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P00CA

P00CAFuel Pressure Regulator A Solenoid Supply Voltage Control Circuit High

P00CA indicates that the powertrain control module (PCM) has detected an abnormally high voltage on the supply control circuit for the fuel pressure regulator A solenoid. This means the circuit is likely shorted to voltage, open, or the solenoid itself has failed, preventing the PCM from properly regulating fuel pressure.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or stumbling during acceleration due to incorrect fuel pressure
Reduced engine performance or power, especially under load
Poor fuel economy or rich-running conditions
Difficulty starting or intermittent stalling
A gasoline odor from the exhaust or engine bay

Common causes, most likely first

Short to voltage on the supply control circuit wiring
Open or high-resistance connection in the solenoid supply circuit
Failed fuel pressure regulator solenoid
Corroded or damaged electrical connector at the solenoid
Faulty powertrain control module (PCM) driver circuit
Blown fuse or relay supplying power to the solenoid circuit

How to diagnose and fix it

Verify the code with a scan tool and check for related codes in other modules
Inspect the solenoid connector and wiring for corrosion, chafing, or loose pins
Measure resistance of the fuel pressure regulator solenoid and compare to specification
Check for short to voltage on the supply control circuit using a multimeter
Test the PCM driver output with a noid light or oscilloscope if the circuit appears intact
Repair or replace damaged wiring, connectors, or the solenoid as needed
Clear codes and perform a road test to confirm the repair

What Most Techs Miss on P00CA

A shorted solenoid coil can back-feed voltage onto the control circuit, mimicking a wiring short and leading to unnecessary PCM replacement.
The PCM may set P00CA intermittently if the solenoid connector is loose or corroded, so always wiggle-test the harness while monitoring live data.
Some vehicles use a shared power supply for multiple solenoids; a fault in one can affect the voltage seen on the regulator circuit, so check for other codes.
A failed fuel pressure regulator solenoid does not always cause driveability symptoms, so the code may be the only clue and should not be ignored.
Aftermarket electrical accessories tapped into the harness can introduce voltage spikes that trigger this code, so inspect for non-factory wiring.

Can I keep driving with P00CA?

You can usually drive the vehicle to a repair shop, but avoid heavy acceleration or towing because incorrect fuel pressure may cause poor performance or increased emissions. If the engine runs rough or stalls, stop driving and have it towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.