P0093: Large leak detected in the fuel system
The ECU sees fuel pressure drop suddenly, as if there were a major leak. It needs checking straight away because of the fire risk.
| Code | P0093 |
|---|---|
| System | Engine and transmission |
| Group | P00xx, Air, fuel and emissions |
| Type | Generic: it means the same on every make |
| Can you keep driving? | Better not |
What P0093 means
The ECU compares fuel pressure with what there should be based on how much fuel it is injecting. If pressure falls much faster than normal, it concludes there is a large leak and stores this code. It is typical of direct injection diesels, and the engine often stalls or goes into limp mode.
Most common causes
- A loose or broken fuel pipe or union (look for wet patches or a smell of diesel or petrol)
- A leak at the fuel filter or its housing
- An injector leaking externally or through the return line
- Rail pressure sensor giving a false reading
- Rail pressure relief valve stuck open
- Internal leak in the high-pressure pump
Symptoms
- Strong smell of fuel
- Diesel or petrol drips under the car or on the engine
- Engine stalls or will not start
- Loss of power and engine warning light on
Can you drive with P0093?
Better not A large fuel leak in the engine bay can start a fire. If you smell fuel or see drips, do not drive; have it recovered.
Open the bonnetthe in-depth explanation
How to check it
With the engine off and cold, look over the engine and under the car for dampness or drips and note any smell. If nothing is visible, compare desired and actual rail pressure in live data to help the garage.
How to read and clear P0093 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0093 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P008F The engine coolant and fuel temperatures do not agree
- P0090 Fuel pressure regulator control circuit fault
- P0091 Fuel pressure regulator control circuit low
- P0092 Fuel pressure regulator control circuit high
- P0094 A small leak has been detected in the fuel system
- P0095 The intake air temperature (bank 1, sensor 2) has an electrical fault
- P0096 The intake air temperature (bank 1
- P0097 Low signal from the intake air temperature sensor
- P0010 Camshaft A actuator control: open circuit (bank 1)
- P0011 Camshaft A timing over-advanced (bank 1)
- P0012 Camshaft A timing over-retarded (bank 1)
- P0013 Camshaft B actuator control: open circuit (bank 1)
To understand it properly
We explain how that system works, with drawings and no waffle, in our mechanics guide: Fuel.
What does code P0093 mean?
The ECU compares fuel pressure with what there should be based on how much fuel it is injecting. If pressure falls much faster than normal, it concludes there is a large leak and stores this code. It is typical of direct injection diesels, and the engine often stalls or goes into limp mode.
Can you drive with P0093?
A large fuel leak in the engine bay can start a fire. If you smell fuel or see drips, do not drive; have it recovered.
How do you clear P0093?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0093 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
