I just purchased a 2015 Tahoe LTZ – my nav system / GPS is also on the fritz –
Onstar indicator on rear view mirror is Red (not green) – indicating a problem, and the GPs map shows me off by at least 50 miles from current position. It was 1800 miles off at purchase (which I didnt notice till after that day!)
CAL shown on dash display (calibrate?) – but I have no restriction from satellite access overhead. When map is visible same GPS with an X through it is visible – meaning no GPS data. Xm works – I figure that runs through same antenna.
Onstar tech says – bad Onstar module, or Antenna. Dealership going to try putting in a new antenna.
Thanks for the insight - and Jfisher320 - was there a number or anything on that TSB?
Lets keep each other posted here.
---------- Post added at 02:13 PM ---------- Previous post was at 01:38 PM ----------
good info here.