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.
What P2404 means
P2404 is a generic OBD-II powertrain code in the emissions group. In plain English: the signal is within electrical limits but doesn’t make sense compared with other readings, so the part or system isn’t performing as expected.
- Check engine light
- Usually on
- Emissions-related
- Yes — can fail inspection
- Limp mode possible
- Not typical
- Drive cycle to clear
- Required
Get it fixed
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Symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Common causes
- 01Pump diaphragm wornMost likely
- 02Reed switch intermittentPossible
- 03Sensor element aged beyond calibration windowLess likely
Can I drive with P2404?
Generally yes.
This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
Why we rate it low
- Turns on the check engine light
- Emissions-related: will usually fail an OBD inspection
- EVAP leaks rarely affect how the car drives
- Needs a drive cycle to confirm a repair
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P2404
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P2404. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Check for related codes first
Look for P2400, P2407. Related codes often share a cause; a circuit or sensor code usually needs fixing before a performance code like this one.
- 3
Test the circuit
Inspect the wiring and connector at the evap leak detection pump and evap pump wiring for damage, corrosion or chafing. With a multimeter, check supply voltage, ground and signal against the specifications in the service manual for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Pump diaphragm worn; reed switch intermittent; sensor element aged beyond calibration window. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and complete a full drive cycle (cold start, idle, steady highway cruise, deceleration). The code is fixed when the related readiness monitor completes without it returning.
P2404 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Yes, with a scan tool
Needs a scan tool and some experience with testing.
Parts and systems involved
- EVAP leak detection pump
- EVAP pump wiring
P2404 FAQ
What does P2404 mean?
P2404 means “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.
Is P2404 serious? Can I keep driving?
We rate P2404 as low severity. Generally yes. This fault is unlikely to affect how the car drives, but it will usually fail an emissions inspection. Fix it when convenient.
What causes P2404?
The most common causes, from most to least likely: Pump diaphragm worn; Reed switch intermittent; Sensor element aged beyond calibration window. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P2404?
Typical labor is about $65–$250 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P2404 myself?
DIY difficulty is moderate. Many owners can handle it with a scan tool, a multimeter and basic hand tools. Always confirm the cause before buying parts.
Will P2404 clear itself?
Once the fault is fixed, the check engine light usually goes off by itself after the system passes its self-test over several drive cycles. Clearing the code with a scan tool resets readiness monitors, so an inspection station may turn you away until a full drive cycle is completed.