2010 GMC Terrain Owner's Manual - Page 237

Driving and Operating The battery could be drained if the key is left in the ACC/ACCESSORY or ON/RUN position with the engine off. The vehicle might not start if the battery is allowed to drain for an extended period of time. D (START): This position starts the engine. When the engine starts, release the key. The ignition switch will return to ON/RUN for normal driving. A warning tone sounds when the driver door is opened if the ignition is still in ACC/ACCESSORY and the key is in the ignition. 8-29 Retained Accessory Power (RAP) These vehicle accessories can be used for up to 10 minutes after the engine is turned off: ... Starting the Engine Move the shift lever to P (Park) or N (Neutral). The engine will not start in any other position. To restart the vehicle when it is already moving, use N (Neutral) only. Notice: Do not try to shift to P (Park) if the vehicle is moving. If you do, you could damage the transmission. Shift to P (Park) only when the vehicle is stopped. Starting Procedure 1. With your foot off the accelerator pedal, turn the ignition key to START. When the engine starts, let go of the key. The idle speed will go down as the engine warms. Do not race the engine immediately after starting it. Operate the engine and transmission gently to allow the oil to warm up and lubricate all moving parts. Audio System Power Windows Sunroof (if equipped) Power to the audio system will continue to operate for up to 10 minutes or until the driver door is opened. Power to the power windows and sunroof will continue to operate for up to 10 minutes or until any door is opened. All these features will work when the key is in ON/RUN or ACC/ ACCESSORY.