Circuit/System Description

The fuel pump 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 GMLAN 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.