Customer Sat Program ended in 2017...
SUBJECT: Loss of GPS, OnStar® and XM Antenna Functions
MODELS: 2015 Cadillac Escalade, Escalade ESV 2015 Chevrolet Silverado Crew Cab, Suburban, Tahoe 2015 GMC Sierra Crew Cab, Yukon, Yukon XL
https://static.nhtsa.gov/odi/tsbs/2015/SB-10089829-2280.pdf