A large fuel leak usually risks fire, so stop when safe, switch off the engine and have it checked before driving on.
Trouble codes · P0093
P0093 meaning
Fuel System Leak Detected - Large Leak
The same first verdict Car Assist shows from this code alone, before a diagnosis. The code does not tell the app whether the warning light is flashing.
What this code doesn’t tell you
A code says where the car noticed a problem. It does not prove which part failed, whether the fault is still present, or what repair this car needs. The engine, other codes, freeze frame and live readings matter.
Usual causes, most likely first
The order is a starting point across cars; the exact engine and its readings can change it.
- Leaking high-pressure fuel pipe or union
- Leaking injector or injector return
- Faulty fuel pressure sensor or regulator
What you can check
With the engine off, look under the bonnet and on the ground beneath the car for fuel, and notice any fuel smell, without touching anything. Usually a fuel smell or visible leak needs the engine switched off and the car not restarted until it has been checked; diesel fuel systems run at very high pressure.
Words the car uses
- Stored codes
- Faults the car has confirmed and saved. They help explain a check-engine light, but a code alone does not prove which part needs replacing.
- Freeze frame
- A snapshot of the engine's readings when a fault was recorded. It helps show the conditions that caused the fault, even if the car now seems fine.
- Readiness monitors
- The car's own checks of its emissions systems. An unfinished check means the car has not tested that system yet, so a clean code scan may miss a fault.
- Fuel supply pressure
- The pressure supplying fuel to the engine. Too little or too much can cause hard starting or poor running.
Find out what’s causing yours
Car Assist reads your car through an OBD-II adapter and your iPhone. Its assistant uses the codes, freeze frame and live readings to work through the likely cause with you.