The vehicle’s computer activates the fuel pump relay, which powers the fuel pump. When activated, voltage is delivered to the pump, in addition to pressurizing the fuel system. There are vehicle models that have a feedback circuit, where voltage is provided to the fuel pump.
This feedback circuit is constantly monitored by the PCM to ensure that the necessary voltage is being sent to the fuel pump. If a high voltage is detected when the pump is not activated, the DTC P0232 OBDII code will be set next to the Check Engine lamp.