Diagnostic Aids

WARNING: This page is about a different car, the 2021 Chevrolet Tahoe and 2021 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

It is critical to use the service replacement K73 Telematics Communication Interface Module only in the vehicle for which it was ordered.
Failure to perform the following procedures will result in a red LED, DTC(s) being set, and limited or incomplete OnStar® services.
An OnStar® button press to the OnStar® call center is required to complete the module replacement procedure.
To fully activate an OnStar® module, both the setup and activation request procedures must be completed on all vehicles with and without an active OnStar® subscription to insure the unit has been setup properly for the vehicle it has been installed into and also to update the OnStar® with the correct unit information.
To initialize the Turn-by-Turn feature (if equipped), the vehicle must first be driven In open sky condition at speeds greater than 10 mph (16 kph) or more for a minimum of 5 miles (8 km), and perform at least 2 left and 2 right 90 degree turns coming to complete stops prior to each turn.
On vehicles up fitted with TTY capabilities, it is necessary to perform a power cycle of the OnStar® Interface Module (OTIM), and toggle the TTY mode after completing the Communication Interface Module installation and setup procedures.