Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The fuel pump flow control module (FPCM) controls and monitors the operation of the fuel system. When the FPCM detects a fault and sets a DTC, the FPCM sends a serial data message to the engine control module (ECM) requesting the illumination of the malfunction indicator lamp (MIL). This DTC sets in the ECM when it receives a MIL request message from the FPCM.