2002 GMC Envoy Owner's Manual - Page 331

The engine air cleaner/filter assembly has an indicator that lets you know when the air filter is dirty and needs to be serviced. The indicator is located on the engine air cleaner/filter air duct. After changing the engine air cleaner/filter, press the button on top of the indicator to reset it. See "Owner Checks and Services" in the Index to determine when to check the indicator. To replace the engine air cleaner/filter, do the following: 1. Remove the three screws on the engine air cleaner/filter and lift off the cover. 2. Twist out the old engine air cleaner/filter and replace it with a new one. See "Engine Compartment Overview" in the Index for more information on engine air cleaner/filter indicator location. The service window (A) with the percentage scale shows the amount of engine air cleaner/filter life used. When both service window (A) and service window (B) turn orange, replace the engine air cleaner/filter. 3. Reinstall the cover. 6-16