How to Clear Diagnostic Trouble Codes

How to clear the codes:

Press the OnStar button within 3 seconds after the second DTC cycle.

How to enter demonstration mode:

1. When ignition switch is turned OFF within 3 sec after DTC, system will be shifted to demonstration mode.
2. Each signals will be appear in order below.
- 2 sec after ignition switch is OFF: Door lock
- 1 sec after door lock: door: Door unlock
- 1 sec after door unlock: Horn and exterior lights period of 0.7 sec.