The engine computer monitors the voltage of the EVAP leak detection pump sense circuit. A P2406 code indicates that the voltage is higher than the normal operating range, typically signifying an electrical open or short in the circuit.
Internal electrical failure of the pump causing an open circuit in the sense line.
Frayed, broken, or corroded wires in the sense circuit causing high voltage readings.
Oxidation or loose pins at the pump connector interrupting the signal path.
Internal failure of the integrated pump or valve assembly.
Internal failure of the engine control module's monitoring circuit.
No, this is an electrical circuit code. It indicates the computer cannot sense the pump's operation, which is distinct from a physical leak code.
No. P2406 is almost always caused by a failed pump or wiring issues. Replacing the PCM without first verifying the circuit is usually the wrong repair.
Yes, the vehicle will remain drivable, but it will not pass an emissions inspection until the circuit is repaired.