Evaporative Emission System Leak Detection Pump Control Circuit
There's a problem with the control circuit for the EVAP leak detection pump.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The car's computer is trying to activate the leak detection pump but isn't getting the expected signal back, which suggests an electrical issue or a fault with the pump itself.
What the computer is actually seeing
When the ECM sends a signal to turn on the evaporative emissions (EVAP) leak detection pump, it expects to see a certain voltage feedback. If it sends a 5V signal and gets less than 1V back, it throws the P2401 code.
What a healthy reading looks like
Expected voltage at the leak detection pump control wire should be between 0.5V and 12V when active; ideally 5V during operation.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the fuse for the leak detection pump; replace if blown.
- 22. Inspect the wiring and connectors leading to the leak detection pump for damage, corrosion, or loose connections; repair as necessary.
- 33. Using a multimeter, measure the voltage at the EVAP pump connector when the ignition is on. It should be around 5V; if not, the issue is upstream (wiring or ECM).
- 44. If voltage is good, apply direct battery voltage to the pump; if it runs, the pump is good, and the issue is likely a control circuit failure. If not, replace the pump.
Common causes
- Faulty leak detection pump
- Corroded or damaged wiring
- Poor electrical connections
- Faulty ECM
- Defective relay for the pump
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable but should be fixed soon to avoid emissions issues.
Will the code come back if I reset it?
If the underlying issue isn't fixed, the code will likely return.
Why does this sometimes pair with P0442?
P0442 indicates a small leak, and both codes relate to the EVAP system, often triggering together due to failures in the same area.
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