The EVAP (Evaporative Emissions Control System) leak detection pump turns on once the ignition is off. This pump creates a vacuum in the EVAP system under the supervision of the Powertrain Control Module (PCM). It looks for possible leaks and checks for proper operation of the EVAP system actuator.
When the P2402 OBDII error code P2402 is stored, it indicates that the EVAP system leak detection pump controller circuit has a high voltage signal return.