15303 - SERVICE UPDATE. THIS BULLETIN PROVIDES A SERVICE PROCEDURE FOR CERTAIN 2015 MODEL YEAR CHEVROLET TAHOE AND CHEVROLET SUBURBAN, GMC YUKON AND GMC YUKON XL 2WD VEHICLES EQUIPPED WITH AUTO LEVELLING REAR SUSPENSION (RPO Z85 AND AVF). THESE VEHICLES MAY HAVE AN AUTO-LEVELING FEATURE THAT IS INOPERATIVE. THE AUTO-LEVELING FEATURE WORKS BY SENSING WHEN THE REAR OF THE VEHICLE IS LOADED. REAR SHOCK ABSORBERSÂ’ INTEGRAL AIR SACKS (BOOTS) ARE INFLATED TO COMPENSATE AND LEVEL THE VEHICLE. CUSTOMERS MAY NOTICE THE REAR TRIM HEIGHT LOWER IN THE REAR OF THE VEHICLE WHEN LOADED COMPARABLE TO VEHICLES WITHOUT AUTO-LEVELING REAR SUSPENSION.
