P0093: Fuel System Leak Detected (Large Leak)
The engine computer sees fuel pressure dropping faster than injection can explain, so it suspects a large leak. Common on diesels.
Green, yellow, red: three ways P0093 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
You ran out of fuel or just changed filters, bled it, and it hasn't returned.
Schedule a repair
Code returns with no visible leak. Get it diagnosed promptly; it could be an internal leak.
Stop and get help
Fuel visible on the engine, a strong fuel smell, or shutdown. Stop now. High-pressure diesel fuel can cause fires and injection injuries.
Symptoms you might notice
- Engine shutdown or derate
- Fuel smell
- Hard starting
Common causes, cheapest first
- External fuel leak at lines or fittings
- Internal leak from an injector or pressure relief valve
- Running out of fuel or air in the fuel
- Faulty rail pressure sensor
What you can check before calling
- Look for wet fuel on the engine and frame (don't touch running fuel lines)
- Check the fuel level
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More fuel & air mixture codes
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0093 mean?
P0093 means "Fuel System Leak Detected (Large Leak)". The engine computer sees fuel pressure dropping faster than injection can explain, so it suspects a large leak. Common on diesels.
Can I drive with code P0093?
It depends on what the vehicle is doing. Green: You ran out of fuel or just changed filters, bled it, and it hasn't returned. Yellow: Code returns with no visible leak. Get it diagnosed promptly; it could be an internal leak. Red: Fuel visible on the engine, a strong fuel smell, or shutdown. Stop now. High-pressure diesel fuel can cause fires and injection injuries.
What causes P0093?
The most common causes are: external fuel leak at lines or fittings; internal leak from an injector or pressure relief valve; running out of fuel or air in the fuel.
Is P0093 a serious code?
It can be. Fuel visible on the engine, a strong fuel smell, or shutdown. Stop now. High-pressure diesel fuel can cause fires and injection injuries.
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