2010 Cadillac CTS Owner's Manual - Page 135

Instruments and Controls An emission system malfunction might be corrected... 4-25 Make sure the fuel cap is fully installed. See Filling the Tank on page 8‑52. 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. If the vehicle has been driven through a deep puddle of water, the vehicle's electrical system might be wet. The condition is usually corrected when the electrical system dries out. A few driving trips should turn the light off. Make sure to fuel the vehicle with quality fuel. 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, 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 will require at least one full tank of the proper fuel to turn the light off. See Gasoline Specifications on page 8‑50. Emissions Inspection and Maintenance Programs Some state/provincial and local governments have or might begin programs to inspect the emission control equipment on the vehicle. Failure to pass this inspection could prevent getting a vehicle registration. Here are some things to know to help the vehicle pass an inspection: . . The vehicle will not pass this inspection if the check engine light is on with the engine running, or if the ignition is placed in ON/RUN and the light is not on. If none of the above have made the light turn off, your dealer/retailer can check the vehicle. The dealer/retailer has the proper test equipment and diagnostic tools to fix any mechanical or electrical problems that might have developed.