VOLVO
EFI-0056 - Fuel pressure sensor (high pressure). Faulty signal
System
Electronic Fuel Injection (EFI)
Volvo models this fault code applies to
This fault code has different meanings depending on model, model year or engine. Select the meaning that applies to your car.
Applies to the following models:
2 modelsS40 (1996–2004), V40 (1996–2004)
Show models by year and engine (2)
What does this fault code mean?
The signal from the high-pressure fuel pressure sensor, which the control module uses for the fuel system, is faulty. The fault lies in the sensor or in the wiring and connectors to it. When the fault is active the malfunction indicator lamp comes on and performance may suffer.
Possible causes
- Defective fuel pressure sensor
- Fuel pressure sensor circuit shorted to ground or supply voltage
- Open circuit in the fuel pressure sensor circuit
- Contact resistance
What you can do
- 1Switch off all electrical equipment that draws power from the battery, such as lights and radio, then read the fuel pressure with the engine running if you have diagnostic equipment
- 2Check the connectors at the control module and the sensor for contact resistance and oxidation, and remedy as needed
- 3Use a multimeter to check that the wiring between the fuel pressure sensor and the control module has no break
- 4Check that the wiring is not shorted to earth, and repair any damage found
- 5If the wiring is fault-free, have a workshop replace the fuel pressure sensor and confirm the code does not return
Symptoms you may notice2
- Malfunction indicator lamp (MIL) comes on
- Reduced performance
What the fault can affect1
- The control module has no substitute values to fall back on
General guidance for car owners. Diagnosis on the car can point to a different cause.