Malfunction Indicator Light
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.
As a bulb and system check, the MIL will illuminate when ignition switch is turned to ON position and engine is not running. When engine is started, MIL should go out. If MIL does not go out, a malfunction has been detected in the computerized engine control system or MIL circuit is faulty. MIL may be used on some models to display a stored DTC. To access DTCs, see SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C", "K" & "N" SERIES - FLEX FUEL & GASOLINE article.