Tighten Fuel Cap
WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) illuminates the TIGHTEN FUEL CAP message in the driver information center (DIC) when the powertrain control module (PCM) detects a low fuel pressure condition. The IPC receives a class 2 message from the PCM requesting illumination.