Universal (All Makes) Vehicle (OBD-II)
Severity:Common Causes
- map[cause:Open circuit — broken wire in the pump control harness]
- map[cause:Disconnected or loose pump connector]
- map[cause:Internal open in the leak detection pump motor winding]
- map[cause:Corroded connector pins preventing current flow]
- map[cause:Blown relay or fuse in the EVAP pump circuit]
How to Fix It
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Check for blown fuses in the EVAP system fuse circuit.
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Confirm the pump connector is fully seated and not corroded.
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Test continuity of the pump control wire from connector to ECM.
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Measure pump motor resistance — an open (infinite) reading means the pump is bad.
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Repair the open wiring or replace the leak detection pump as needed.
Frequently Asked Questions
What's the difference between P2400, P2401, and P2402?
P2400 is an open circuit fault. P2401 means the circuit voltage is too low (short to ground). P2402 means the circuit voltage is too high (open circuit or short to power).
Does this affect gas mileage?
Not directly. The pump is only active during EVAP system self-tests, not during normal driving.
Can I clear the code and just drive?
You can clear it, but it will return if not fixed. The root cause must be repaired for it to stay gone.