Check Gas Cap Message
WARNING: This page is about a different car, the 2004 Chevrolet Monte Carlo and 2004 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
The powertrain control module (PCM) sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when any of the following occur:
- A malfunction in the evaporative emission (EVAP) system and a large leak test fails
- A malfunction in the EVAP system and a small leak test fails