P2404
EVAP Leak Detection Pump Sense Circuit Range/Performance
The sense (reed-switch or current-feedback) signal from the leak-detection pump is electrically valid but does not match expectations during a leak test. Often a worn pump diaphragm or a sticking reed contact.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
Ordered by how often each turns out to be the cause.
- Pump diaphragm wornCommon
- Reed switch intermittentPossible
- Sensor element aged beyond calibration windowLess likely
Parts involved
- EVAP Leak Detection Pump
- EVAP Pump Wiring
P2404 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.