Tighten Gas Cap
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) illuminates the TIGHTEN GAS CAP message in the driver information center (DIC) when the engine control module (ECM) detects a low fuel pressure condition. The IPC receives a class 2 message from the ECM requesting illumination.