P0094: Fuel System Leak Detected - Small Leak

What it means

The control module detected a small leak or loss of pressure in the fuel system. The code does not identify the location or prove that an injector or fitting is leaking.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The fuel system maintains pressure so the engine receives the required fuel, while the control module monitors pressure for signs of loss. P0094 indicates a pressure loss meeting the system's small-leak threshold; it may reflect a minor leak or an inaccurate pressure signal, and does not identify a leaking part.

Common causes

Most likely first.

1. Fuel line, fitting, or seal leaking
2. Injector seal or return connection leaking
3. Pressure sensor or wiring fault causing a false leak indication

Symptoms

• Check engine light on
• Loss of power or engine hesitation
• Hard starting or extended cranking
• Fuel odor may be present

How to diagnose it

1. Review freeze-frame data and fuel-pressure readings to see when the small pressure loss was detected and whether it coincided with extended cranking or hesitation.
2. With the engine off, inspect accessible fuel lines, fittings, injector seals, and return connections for dampness, residue, or fuel odor.
3. Check the pressure sensor connector and wiring for loose or corroded terminals that could distort the reported pressure.
4. If no leak is visible, test fuel pressure and pressure retention against the manufacturer's specification to look for a small or hidden loss.
5. Compare pressure-sensor data with test measurements before deciding whether a leak or sensor circuit fault is responsible.

Common fixes

• Repair a leaking fuel-line fitting, seal, or return connection.
• Replace a fuel line or injector seal confirmed to be leaking.
• Clean or repair a loose or corroded pressure-sensor connection.
• Replace the pressure sensor only if its readings fail verification.

Can I keep driving?

If you smell fuel or see a leak, stop the engine and do not drive until it is repaired. If there is no sign of external fuel and the engine runs normally, limit driving and watch for worsening hesitation or stalling.