Module, Fuel Pump: Operation: Operation
WARNING: This page is about a different car, the 2012 Jeep Patriot and 2012 Jeep Compass. However, it is still accessible from the selected car via links, so may be relevant.
When the PCM senses the ignition switch in the On, Crank or Run mode, battery positive voltage is supplied from the ASD relay and the TIPM to the fuel pump relay. The PCM will also ground the fuel pump relay driver at this time, closing the fuel pump relay contacts, completing the fuel pump circuit to chassis ground. If the PCM senses the ignition in the ON position, without a engine crank signal for more than 30 seconds, it will open the fuel pump driver circuit, turning off the fuel pump.
The regulated fuel lift pump, in On and Crank mode will produce approximately 4 bar (58 psi) to maintain constant fuel pressure to the high pressure injection pump.