GMC Yukon 2021 Owner's Manual page 390

Maintenance Schedule Additional
Required Services - Severe
Rotate tires and perform Required Services. Check engine oil
level and oil life percentage. Change engine oil and filter,
if needed. Check engine air filter life percentage and status.
Change engine air filter, if needed.
Replace passenger compartment air filter. (1)
Inspect evaporative control system. (2)
If the vehicle is not equipped with the engine air filter life
system, replace engine air cleaner filter. (3)
Change automatic transmission fluid and filter.
Change transfer case fluid, if equipped with 4WD. (4)
Replace spark plugs. Inspect spark plug wires and/or boots.
Drain and fill engine cooling system. (5)
Visually inspect accessory drive belts. (6)
Replace brake fluid. (7)
Replace front and rear wiper blades. (8)
Replace hood and/or body lift support gas struts. (9)
Replace air conditioning desiccant. (10)
Footnotes Maintenance Schedule
Additional Required Services - Severe
(1) Or every two years, whichever comes
first. More frequent passenger compartment
air filter replacement may be needed if
driving in areas with heavy traffic, poor air
quality, high dust levels, or environmental
allergens. Passenger compartment air filter
replacement may also be needed if there is
Service and Maintenance
reduced airflow, window fogging, or odors.
Your GM dealer can help determine when to
replace the filter.
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