P2401 indicates that the Engine Control Module has detected a low voltage condition in the Evaporative Emission System Leak Detection Pump control circuit. This usually means the pump is not receiving enough power or the signal is being pulled low.
Open, shorted, or corroded wires or connectors in the pump control circuit can cause a low voltage reading.
The pump itself may have an internal short or failed driver, preventing it from drawing the proper voltage.
A defective relay or a partially blown fuse can limit voltage to the pump circuit.
A poor chassis ground or a bad voltage reference sensor can cause the control module to see a low voltage.
Only after ruling out all hardware issues should a rare ECM output driver fault be considered.
No. In the overwhelming majority of cases the problem is a wiring, pump, relay, or fuse issue. Replacing the PCM is rarely needed and is not the first‑line solution.
The code will not clear automatically. After repairing the underlying fault, the ECM must complete a successful pump test cycle, which may require a drive cycle or a manual reset.
Yes. A malfunctioning pump can trigger additional EVAP‑related codes such as P0455 (large leak) or P0442 (small leak) because the system cannot pressurize correctly.
A scan tool that can read live data and perform EVAP system tests is helpful, but a multimeter and basic wiring inspection tools are sufficient for most diagnoses.