2007 Cadillac STS Owner's Manual - Page 254

Did you just drive through a deep puddle of water? If so, your vehicle's electrical system may be wet. The condition will usually be corrected when the electrical system dries out. A few driving trips should turn the light off. Have you recently changed brands of fuel? If so, be sure to fuel your vehicle with quality fuel. See Gasoline Octane on page 365. Poor fuel quality will cause the engine not to run as efficiently as designed. You may notice this as stalling after start-up, stalling when you put the vehicle into gear, misfiring, hesitation on acceleration, or stumbling on acceleration. (These conditions may go away once the engine is warmed up.) This will be detected by the system and cause the light to turn on. If you experience one or more of these conditions, change the fuel brand you use. It will require at least one full tank of the proper fuel to turn the light off. If none of the above steps have made the light turn off, your dealer can check the vehicle. Your dealer has the proper test equipment and diagnostic tools to fix any mechanical or electrical problems that may have developed. 254 Emissions Inspection and Maintenance Programs Some state/provincial and local governments have or may begin programs to inspect the emission control equipment on your vehicle. Failure to pass this inspection could prevent you from getting a vehicle registration. Here are some things you need to know to help your vehicle pass an inspection: Your vehicle will not pass this inspection if the check engine light is on or not working properly. To perform a check engine light bulb check with the keyless ignition, make sure the transmitter fob is in the passenger compartment. See Ignition Positions on page 111. Press the bottom of the Acc. button on the instrument panel and hold the button down for five seconds. The instrument panel, including the check engine light, will light up and the ignition will be on, but the engine will not start - if you press the bottom of the Acc. button only briefly, less than five seconds, the accessory power mode will be turned on, but not the ignition. After the bulb check, be sure to press and release the Acc. button again to turn the ignition off and avoid draining the vehicle's battery.