Fuel and air

P00CA — Fuel Pressure Regulator Solenoid Supply Voltage Circuit High

Severity: medium Drive with care, to a shop

What P00CA means

The engine control module drives a solenoid on the fuel pressure regulator and monitors the voltage in its circuit. P00CA sets when that voltage is higher than expected. Common causes are wiring or connector faults, a failing solenoid or regulator, and, less often, a driver fault inside the ECM. Fuel rail pressure may then be controlled incorrectly.

Symptoms

  • Check Engine light on
  • Reduced engine power or hesitation
  • Worse fuel economy
  • Hard starting or long cranking
  • Rough running or stalling
  • Limp mode

Possible causes

  1. Damaged wiring or corroded connectors in the solenoid circuit (most common)
  2. Failed fuel pressure regulator solenoid
  3. Faulty pressure regulator or volume control valve
  4. Faulty fuel rail pressure sensor
  5. Low-pressure supply problem: pump, filter or lines
  6. Worn or failing high-pressure pump
  7. Excess injector return flow
  8. ECM fault (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other fuel pressure codes
  2. Inspect the harness and connectors at the regulator and pressure sensor for chafing and corrosion
  3. Check supply voltage, control signal and ground at the solenoid connector
  4. Measure solenoid resistance and compare it with the spec
  5. Test low-pressure fuel supply pressure and volume
  6. Compare commanded and actual rail pressure at cranking, idle and under load
  7. Run an active test of the regulator or control valve if the scan tool supports it
  8. Where applicable, measure injector return flow

Common fixes

  • Repair wiring and clean or replace connectors
  • Replace the fuel pressure regulator solenoid
  • Replace the pressure regulator or volume control valve
  • Fix low-pressure supply faults such as the pump, filter or lines
  • Reflash or replace the ECM once it is confirmed faulty

Questions and answers

What does P00CA mean?

It means the ECM detects high voltage in the fuel pressure regulator solenoid circuit. The module may not be able to control rail pressure properly. Wiring or the regulator itself is the usual cause.

Can I drive with P00CA?

Only briefly and to a repair shop. Power loss, hard starting and stalling are possible, so do not put the repair off.

Where should I start diagnosing P00CA?

Start with a visual check of the regulator wiring and connectors, then test solenoid voltage and resistance. After that, compare actual and commanded fuel pressure with a scan tool.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.