Fuel filler door lock actuator faulty (internal short or seized motor or solenoid); Wiring to the actuator shorted to ground or chafed, often near the rear wheel arch or filler area; Corroded, damaged or water-affected connector at the actuator or in the boot or rear quarter; Blown fuse or a fault on the shared power or ground supply for the actuator circuit; Faulty driver stage inside the controlling module (body or central locking module); Outdated or faulty control module software on certain models.

P04C1

Fuel Fill Door Unlock Control Circuit Low.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
C1: FaultThe specific fault in that area

What it means

P04C1 means the control module that operates the fuel filler door unlock saw a low voltage on the unlock control circuit when it commanded or monitored it. This usually points to a short to ground, a high-resistance fault or a failed actuator pulling the circuit down. The layout depends on the vehicle, because the function may sit in a body control module, a central locking module or another controller.

Symptoms

Fuel filler flap will not release or unlock
Fuel filler flap stays locked after the car is unlocked
Warning light or message about the fuel door or a general fault
Fuel flap release button or central locking release does nothing
Fuel flap unlocks at the wrong time or will not stay locked

Possible causes

Fuel filler door lock actuator faulty (internal short or seized motor or solenoid)likely
Wiring to the actuator shorted to ground or chafed, often near the rear wheel arch or filler arealikely
Corroded, damaged or water-affected connector at the actuator or in the boot or rear quarterpossible
Blown fuse or a fault on the shared power or ground supply for the actuator circuitpossible
Faulty driver stage inside the controlling module (body or central locking module)rare
Outdated or faulty control module software on certain modelsrare

How to diagnose

Read all stored and pending codes and the freeze frame data, and note whether other body or central locking codes are present
Check the fuel flap operation by hand and by the release control, and listen for the actuator working
Inspect the actuator, its wiring and connectors for water, corrosion, chafing or pinched cables
Check the relevant fuse and the power and ground supplies to the circuit using the wiring diagram for the model
Measure the control circuit voltage with the actuator connected and disconnected to separate an actuator fault from a wiring short
Test the actuator resistance and operation against the manufacturer specification
Check for a wiring short to ground by testing continuity between the module and actuator with the connectors unplugged
Check for a software update or technical bulletin for the model if the wiring and actuator test fine

How to fix

Replace the fuel filler door lock actuator if it is shorted or seized
Repair or replace damaged wiring and fix the cause of any chafing
Clean or replace corroded connectors and make sure they are properly sealed
Replace the blown fuse after finding what overloaded the circuit
Repair or replace the controlling module only after the wiring and actuator are proven good
Update the module software if a known fault for that model is confirmed

Can I keep driving?

Low severity

The car can normally be driven as usual, as this fault does not affect engine or braking. The main concern is being unable to open the fuel flap, so check the handbook for the manual release and get it repaired before the tank runs low.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.