P2404
EVAP System Leak Detection Pump Sense Circuit Range/Performance
Evaporative emissions (EVAP)
Generic OBD-II
Low
What it means
P2404 means the signal from the EVAP leak-detection pump's sense circuit is out of its expected range — the pump the ECM uses to check the fuel-vapor system for leaks is not reporting correctly. It is usually a pump, wiring, or connector problem, sometimes a loose fuel cap or an actual EVAP leak. The car drives normally, but it will not pass an emissions test until the monitor works again.
Low
Can I keep driving? Yes — the car runs and drives normally. This is an emissions-monitoring fault, so the main consequences are the warning light and an emissions-test failure.
Common symptoms
What you'll notice
- Check-engine light on
- Fails an emissions/readiness test
- No noticeable change in how the car runs
- Possible faint fuel smell only if a real EVAP leak is also present
Common causes
Most likely first
- Faulty EVAP leak-detection pump (LDP) or its sense circuitLikely
- Open, shorted, or corroded wiring or connector at the LDPCommon
- Loose, wrong, or damaged fuel filler capCommon
- Leaking EVAP hose, canister, or fuel tank affecting the pump's readingsLess often
- Debris caught in the filler-cap or LDP filterLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fuel cap is the correct type and tightened until it clicks.
- Inspect the LDP connector and wiring for damage, corrosion, or a loose pin.
- Check EVAP hoses and the canister for cracks or leaks.
- Test the leak-detection pump's operation and sense-circuit signal against spec.
- Replace the LDP or repair the wiring as needed, then clear the code and re-test.
FAQ
Quick answers
Is it safe to drive with P2404?+
Yes — it does not affect running or safety. It means the system that checks for fuel-vapor leaks is not reporting correctly, so you will fail an emissions test.
Can I just clear P2404?+
Tightening or replacing the fuel cap sometimes clears a cap-related trip, but a pump or wiring fault will return once the monitor re-runs.
Related codes
Often seen with P2404
Read & clear P2404 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX