P2C04 code meaning
Fuel Pressure Regulator D Control Circuit High
Powertrain system Generic code P2Cxx codes Check engine light
What P2C04 means
P2C04 covers the opposite electrical fault to P2C03: the switched ground end of the regulator D circuit is connected to battery voltage. In GM's 23OBDG07 and 24OBDG07 tables the circuit belongs to the second fuel quantity control valve, counterpart of P0092 on the first. The ECM detects it while the driver is switched on: the line should then be pulled down, and if the voltage stays high, the module assumes a short of less than 0.5 ohm to the injector supply. Enable conditions are supply above 10.9 V and engine speed above 80 rpm; 20 failed events set the code on the first trip. As long as the short exists the valve cannot be switched, so pump output for that circuit is lost. Look for insulation damage where the harness runs near hot or moving parts, and for moisture in the connector.
P2C04 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2C04
- Check engine light on
- Reduced power, possibly limp mode
- Engine may hesitate under load
Common causes of P2C04
- Most likelyLow-side wire shorted to a supply voltage
- PossibleMoisture or corrosion bridging pins in the valve connector
- Less likelyFaulty output stage in the engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel pressure regulator dHigh pressure fuel pumpWiring harness
What each part of P2C04 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| C | Area: hybrid propulsion. |
| 04 | The exact fault in that area. |
What to do next
- Note P2C04 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2C04
What does P2C04 mean?
P2C04 means "Fuel Pressure Regulator D Control Circuit High". P2C04 covers the opposite electrical fault to P2C03: the switched ground end of the regulator D circuit is connected to battery voltage. It is a generic code, so it means the same on every make.
Is it safe to drive with P2C04?
Drive gently and only to a workshop. With P2C04 the car can go into limp mode (reduced power) to protect itself.
Will P2C04 fail an emissions test?
Yes, it can. P2C04 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2C04 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2C04 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.