2003 GMC Envoy Owner's Manual - Page 315

Engine Air Cleaner/Filter , ~~ - The engine cleaner/filter air is located toward the front of the engine compartment on the passenger's side of the vehicle. Your vehicle may have this feature. The engine air cleanedfilter 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. 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. After changing the engine air cleaner/filter, press the button on top of the indicator to reset it. For vehicles without an indicator, refer to the maintenance schedule to determine when to replace the engine air cleaner/filter. See Engine Compartment Overview on page 5-12 for more information on engine air cleaner filter location. 5-20