P00C8: Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit/Open

What it means

Open circuit on the supply voltage feed to the fuel pressure regulator A solenoid.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

Fuel pressure regulator A uses a solenoid to help control fuel pressure, and its supply circuit provides the power needed for that solenoid. P00C8 means the control module detects an open in the supply-voltage circuit to regulator A; it identifies a circuit fault but does not prove that the solenoid itself has failed.

Common causes

Most likely first.

1. Supply wiring open
2. Pin pushed back out of connector body
3. Cracked solder joint inside the module or sensor

Symptoms

• Check engine light on
• Hard start, no start, or stalling under load
• Power loss especially at high load or rpm
• Possible long cranking time

How to diagnose it

1. Record freeze-frame data and check for related fuel-pressure or regulator codes to understand whether the open coincided with a starting or load problem.
2. Inspect the regulator A connector for a backed-out pin, corrosion, poor seating or heat damage.
3. Trace the regulator A supply wire for breaks, chafing or damage, paying particular attention to harness bends and connector entries.
4. With the circuit safely isolated as required, check supply-circuit continuity between regulator A and its feed point.
5. Check the fuse, relay and module-side connections, then test the circuit and solenoid using the manufacturer's procedure.

Common fixes

• Reseat a loose regulator A connector or pin.
• Repair an open or damaged wire in the regulator A supply circuit.
• Replace a failed fuse or relay after finding and correcting the cause.
• Replace a faulty connector or terminal with poor contact.
• Repair a confirmed internal module fault or replace the regulator A solenoid if its own testing shows failure.

Can I keep driving?

Avoid driving if the engine is hard to start, stalls or loses power under load, since it may stop unexpectedly. A vehicle that runs normally may still fail to restart or develop fuel-pressure problems.