2015 Buick Regal Owner Manual - Page 131

5-22 Instruments and Controls or stumbling on acceleration. These conditions might go away once the engine is warmed up. If one or more of these conditions occurs, change the fuel brand used. It may require at least one full tank of the proper fuel to turn the light off. See Fuel on page 9-59. If none of the above have made the light turn off, your dealer can check the vehicle. The dealer has the proper test equipment and diagnostic tools to fix any mechanical or electrical problems that might have developed. Light On Steady: An emission control system malfunction has been detected on the vehicle. Diagnosis and service might be required. The following may correct an emission control system malfunction: . Check that the fuel cap is fully installed. See Filling the Tank on page 9-62. The diagnostic system can determine if the fuel cap has been left off or improperly installed. A loose or missing fuel cap allows fuel to evaporate into the atmosphere. A few driving trips with the cap properly installed should turn the light off. Check that good quality fuel is used. Poor fuel quality causes the engine not to run as efficiently as designed and may cause stalling after start-up, stalling when the vehicle is changed into gear, misfiring, hesitation on acceleration, The DLC is under the instrument panel next to the steering wheel. See your dealer if assistance is needed. The vehicle may not pass inspection if: . Emissions Inspection and Maintenance Programs Depending on where you live, your vehicle may be required to participate in an emission control system inspection and maintenance program. For the inspection, the emission system test equipment will likely connect to the vehicle's Data Link Connector (DLC). . The malfunction indicator lamp is on while the engine is running, or the malfunction indicator lamp is not on while the vehicle is in ON/RUN or Service Only Mode. See your dealer for assistance in verifying proper operation of the malfunction indicator lamp.