Output Mode
When the ignition switch is turned OFF within 3 seconds after the final DTC is displayed, the OnStar control unit will enter the Output Mode and operate the door lock/unlock, horns, parking lights and taillights.
When all operations have completed, the OnStar control unit will exit from the Self-diagnostic Mode and go to Market Mode *.
* Market mode: When the vehicle arrives at the dealership, the OnStar control unit will be in Market Mode. However, if a dealer has to replace the OnStar control unit, the service part will be in Shipping Mode. The dealer will need to go through the button press sequence to get the unit to transition from Shipping Mode to Market Mode. The dealer will also need to contact OnStar to verify the configuration of the new unit for the customer (see CONTROL UNIT REPLACEMENT ).