Reactivation for Subsequent Owners
Push 
and follow the prompts to speak to an Advisor as soon as possible after acquiring the vehicle.
The Advisor will update vehicle records and will explain the OnStar service offers and options available.
See also:
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays when the vehicle's engine power is reduced. Reduced engine
power can affect the vehicle's ability to accelerate. If this message is on, but
t ...
Special Application Services
• Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000 km/3,000 mi.
• Have underbody flushing service performed once a year. ...
Retrieve My Number
1. Push X. System responds: “OnStar ready.”
2. Say “My Number.” System responds: “Your OnStar Hands-Free Calling number is.” ...