P2404: EVAP System Leak Detection Pump Sense Circuit Range/Performance
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - the fault is confined to the emissions self-test.
Symptoms
- Check engine light only
- Emissions readiness incomplete
- No change in how the car runs
Likely causes, most common first
- Leak detection pump sense circuit reading implausibly
- Pump diaphragm worn
- Blocked pump filter
- Wiring or connector fault
Read P2404 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P2404 means the feedback circuit inside the leak detection pump is reporting something the computer cannot reconcile. The pump both pressurises the system and measures its own effort, and this code says the measurement is not credible.
A blocked filter ahead of the pump produces exactly this result: the pump strains, its feedback looks wrong, and the system reports a sense circuit fault without any electrical problem existing. Checking that filter first is cheap and catches a fair share of these.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Frequently asked questions
Can I drive with P2404?
Yes - the fault is confined to the emissions self-test.
How much does it cost to fix P2404?
Typical US repair costs range from $80 for the simplest fix (leak detection pump) to $700 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to P2404. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.