P04EE — EVAP System Very Small Leak Detected - Fuel Tank Side

Diagnostic algorithm

1. Retrieve freeze frame and live data; confirm P04EE and check EVAP monitor/test status. Note environmental conditions (fuel level, temperature).
2. Inspect fuel cap: remove, inspect seal and threads, reinstall and torque to spec or replace cap and clear code to retest.
3. Visually inspect filler neck, filler neck seal, tank top area, hoses and clamps on the tank side for signs of damage or looseness.
4. Perform low-pressure smoke test while monitoring for smoke at tank seams, hoses, filler neck, canister, and vent valve. Use low pressure to reveal very small leaks.
5. If smoke test is inconclusive, isolate tank side components (cap, filler, tank lines) and pressure/vacuum test the tank with a calibrated hand pump or lab tool per vehicle procedure.
6. Verify canister vent valve and purge valve operation and sealing (commanded closed/open while observing pressure response). Replace or service any component that fails to seal.
7. Inspect and test EVAP pressure sensor and leak detection pump for correct readings and electrical continuity; substitute or bench test if suspect.
8. If a porous tank or inaccessible hairline crack is found, replace the tank or repair per manufacturer-approved methods.
9. After repair, clear DTCs, complete required EVAP readiness drive cycle or run the self-test to confirm the issue is resolved and the code does not return.
10. Safety note: work with EVAP and fuel system components in a well-ventilated area and avoid ignition sources.