2015 Buick LaCrosse Owner Manual - Page 203

9-18 Driving and Operating Service Only Mode This power mode is available for service and diagnostics, and to verify the proper operation of the malfunction indicator lamp as may be required for emission inspection purposes. With the vehicle off, and the brake pedal not applied, pressing and holding the button for more than five seconds will place the vehicle in Service Only Mode. The instruments and audio systems will operate as they do in ON/RUN, but the vehicle will not be able to be driven. The engine will not start in Service Only Mode. Push the button again to turn the vehicle off. ACC/ACCESSORY (Amber Indicator Light): This mode allows you to use some electrical accessories when the engine is off. With the ignition off, pressing the button one time without the brake pedal applied will place the ignition system in ACC/ACCESSORY. The ignition will switch from ACC/ ACCESSORY to OFF after five minutes to prevent battery rundown. ON/RUN/START (Green Indicator Light): This mode is for driving and starting. With the ignition off, and the brake pedal applied, pressing the button once will place the ignition system in ON/RUN/START. Once engine cranking begins, release the button. Engine cranking will continue until the engine starts. See Starting the Engine on page 9-18. The ignition will then remain in ON/RUN. { Caution 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. { Caution If you add electrical parts or accessories, you could change the way the engine operates. Any resulting damage would not be covered by the vehicle warranty. See Add-On Electrical Equipment on page 9-68. Starting the Engine Move the shift lever to P (Park) or N (Neutral). To restart the engine when the vehicle is already moving, use N (Neutral) only.