Fuel and air

P00C8 — Fuel Pressure Regulator A Solenoid Supply Circuit Open

Severity: medium Drive with care, to a shop

What P00C8 means

The engine computer controls rail fuel pressure with a regulator solenoid (a pressure or volume control valve) that it feeds with supply voltage. P00C8 sets when the PCM sees an open or out-of-range condition in that supply circuit. As a result, fuel pressure can no longer be regulated accurately.

Symptoms

  • Check Engine light on
  • Rough idle
  • Hesitation or stumbling on acceleration
  • Loss of power
  • Hard starting or long cranking
  • Poor fuel economy
  • Possible stalling

Possible causes

  1. Open or shorted wiring in the regulator solenoid circuit
  2. Failed fuel pressure regulator solenoid
  3. Corroded or loose connector terminals
  4. Faulty pressure or volume control valve
  5. Low-pressure supply problem: pump, filter or lines
  6. Worn or failing high-pressure fuel pump
  7. Faulty fuel pressure sensor
  8. Failed PCM (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other fuel system codes
  2. Inspect the solenoid wiring and connector for damage, corrosion, chafed insulation and poor terminal tension
  3. Check supply voltage and ground at the solenoid connector with the key on
  4. Test the circuit wires back to the PCM for opens and shorts to ground or voltage
  5. Measure solenoid coil resistance and compare it to the manufacturer spec
  6. Use a scan tool to compare commanded and actual rail pressure at cranking, idle and under load
  7. Test low-pressure fuel supply: pump pressure, volume and filter condition
  8. If wiring and solenoid are good, check the pressure sensor before suspecting the PCM

Common fixes

  • Repair the wiring or replace the damaged connector
  • Replace the regulator solenoid or fuel pressure regulator
  • Replace the fuel filter or low-pressure pump if supply is weak
  • Replace the high-pressure pump or pressure sensor if confirmed faulty
  • Repair or replace the PCM only if everything else tests good

Questions and answers

What does P00C8 mean?

The PCM found an open or fault in the supply voltage circuit of the fuel pressure regulator A solenoid. Wiring, a connector or the solenoid itself is the most common cause.

Can I drive with P00C8?

Only briefly and with caution, for example to a shop. The engine can lose power or stall, so do not put off the repair.

What should I check first for P00C8?

Inspect the solenoid connector and wiring, verify power and ground, then compare commanded and actual rail 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.