Cause
Faulty EVAP leak detection pump
The pump pressurising the fuel system to test it for leaks, which runs hours after the car is parked because vapour pressure follows temperature. A parked car humming to itself is normal, and a pump that never completes its test is a genuine cause of a flat battery overnight — as is a car only used for short journeys, where the test never gets a chance to run.
Typically a moderate job.
Codes this can cause (11)
Codes where this is a likely explanation first, rather than merely a possible one.
- P043E Evaporative Emission System Leak Detection Reference Orifice Low Flow Likely for this code Low
- P2400 Evaporative Emission System Leak Detection Pump Control Circuit Open Likely for this code Moderate
- P2401 Evaporative Emission System Leak Detection Pump Control Circuit Low Likely for this code Moderate
- P2402 Evaporative Emission System Leak Detection Pump Control Circuit High Likely for this code Moderate
- P2404 Evaporative Emission System Leak Detection Pump Sense Circuit Range/Performance Likely for this code Moderate
- P24B9 Evaporative Emission System Leak Detection Pump Pressure Sensor Circuit Range/Performance Likely for this code Low
- P2403 Evaporative Emission System Leak Detection Pump Sense Circuit Open Moderate
- P2405 Evaporative Emission System Leak Detection Pump Sense Circuit Low Moderate
- P2406 Evaporative Emission System Leak Detection Pump Sense Circuit High Moderate
- P2407 Evaporative Emission System Leak Detection Pump Sense Circuit Intermittent/Erratic Moderate
- P24D6 Evaporative Emission System Pressure Sensor/Switch B Circuit Range/Performance Low
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Others who found this
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about Faulty EVAP leak detection pump.