What it means
Same as P04EA but at the most sensitive leak threshold - typically the OBD-II 0.020-inch (~0.5 mm) test. The system holds pressure for some time but loses it slower than the diagnostic limit allows; usually fuel cap O-ring fatigue or microcracks in a hose.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The EVAP system stores fuel vapor and checks whether its sealed tank-side path can hold a test pressure or vacuum. P04EE indicates a very small leak on the fuel-tank side: the system holds briefly but loses pressure or vacuum faster than the monitor allows, often at a cap seal, hose, fitting, or sender-area seal.
Common causes
Most likely first.
- Fuel cap seal aged, stiff, or damaged
- Small crack or leak in a fuel-tank-side EVAP hose
- Leaking tank-side EVAP fitting or seal
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
How to diagnose it
- Review freeze-frame data and EVAP monitor results to confirm the very-small-leak fault and the conditions in which it appeared.
- Inspect the fuel cap seal and filler-neck sealing surface for stiffness, cracks, dirt, or damage, and confirm the cap is seated correctly.
- Examine accessible tank-side EVAP hoses and fittings closely for fine cracks, loose joints, or deterioration.
- Use an approved low-leak-rate EVAP smoke or pressure test to check the tank-side hoses, fittings, and sender-area seal.
- Repair or replace only the component that fails the manufacturer's leakage test.
Common fixes
- Clean the cap and filler-neck sealing surfaces and refit the cap correctly.
- Replace the fuel cap if its seal is aged or damaged.
- Replace a cracked tank-side EVAP hose.
- Repair a leaking tank-side fitting or sender-area seal confirmed by testing.
Can I keep driving?
The vehicle is generally driveable if there is no strong fuel odor or visible leak, but the check-engine light can prevent an emissions inspection from passing. If fuel odor becomes strong or fuel is visibly leaking, stop driving and have it addressed promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.