Starting Mode
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The ECM supplies a high voltage signal to the fuel pump control module (FPCM) when the ECM detects that the ignition is ON. The high voltage signal from the ECM to the FPCM remains active for two seconds, unless the engine is in Crank or Run. While this signal is being received, the FPCM closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure. The ECM calculates the air/fuel ratio based on inputs from the engine coolant temperature (ECT), manifold absolute pressure (MAP), and throttle position (TP) sensors. The system stays in starting mode until the engine speed reaches a predetermined RPM.