Evaporative Emission System Leak Detection Pump Control Circuit Low
This code indicates a problem with the control circuit for the leak detection pump in the evaporative emission system.
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 computer is seeing that the little pump that checks for fuel vapor leaks isn't getting the right signal to turn on, which might mean a wiring issue or a bad pump.
What the computer is actually seeing
The PCM expects a certain voltage (typically around 5V) to signal the leak detection pump's operation, but it’s getting a lower voltage or ground signal instead.
What a healthy reading looks like
5V signal from the PCM to the leak detection pump circuit.
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.
- 1Inspect the wiring and connectors for damage or corrosion at the leak detection pump.
- 2Test the voltage at the leak detection pump connector with the key in the ON position; expect to see around 5V.
- 3If no voltage, check the related fuses and relays for continuity. Replace any faulty components you find.
- 4If voltage is present, connect a known good leak detection pump to see if the issue persists.
Common causes
- Faulty leak detection pump
- Damaged wiring or connectors in the pump circuit
- Faulty PCM
- Corrosion in connectors
- Failed relay if applicable
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, it’s drivable but you should fix it soon to prevent emissions failures.
Will this code come back after clearing it?
If the underlying issue isn’t fixed, yes, the code will likely return.
Why does this code appear with P0456?
Both codes relate to the evaporative emission system; P0456 indicates a small leak, P2402 relates to the pump control.
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