P2404
Evaporative Emission System Leak Detection Pump Sense Circuit Range/Performance
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The P2404 code means the EVAP leak detection pump's sense circuit is reporting readings outside of the normal range. Unlike the P2400-P2402 codes which focus on the pump's electrical control circuit, this code is specifically about the pump's ability to sense pressure or vacuum changes in the EVAP system. The readings are either too high, too low, or erratic.
This code does not affect how your vehicle drives — engine performance, acceleration, and fuel economy will remain normal. However, it does mean the EVAP system cannot properly test itself for leaks, and your vehicle will fail an emissions inspection. In rare cases, you may notice a faint gasoline odor.
Start with the cheapest and simplest check: make sure your gas cap clicks securely and the seal is not cracked or dry. If the cap is fine, visually inspect all EVAP hoses under the vehicle and under the hood for cracks, disconnections, or deterioration. If no obvious issues are found, a professional smoke test can quickly pinpoint any leaks. If the system is sealed properly but the code persists, the leak detection pump itself likely needs replacement.
Severity
Symptoms
- •Check Engine Light is on
- •Vehicle fails emissions inspection
- •Possible slight fuel smell near tank area
- •No noticeable change in engine performance
- •EVAP system unable to complete self-test
Likely Causes
The pump's internal pressure sensor has drifted out of calibration or failed, providing readings outside the expected range.
An actual leak in the EVAP system can cause the pump sensor to report out-of-range performance because it cannot achieve the target pressure.
A gas cap that does not seal properly is one of the most common causes of EVAP system performance codes.
Deteriorated rubber hoses or disconnected fittings in the EVAP plumbing prevent the system from holding pressure during the leak test.
A stuck-open purge or vent valve allows pressure to bleed off during the leak detection pump test.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace EVAP leak detection pump
- Tighten or replace gas cap
- Replace cracked or disconnected EVAP hoses
- Replace purge valve or vent valve
- Perform smoke test to find EVAP system leaks
Shop Parts
Videos
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