1997 Chevrolet Tahoe Owner's Manual - Page 140

Malfunction Indicator Lamp (Service Engine Soon Light) (Gasoline Engine) Your vehicle is equipped with a computer which monitors operation of the fuel, ignition and emission control systems. I NOTICE: If you keep driving your vehicle with this light on, after a while, your emission controls may not work as well, your fuel economy may be as not good and your engine may not as smoothly. run This could lead costly repairsthat may not be to covered by your warranty. This light should come on, as a check to show you it is working, when the ignition is on and the engine is not it running. If the light doesn't come on, have repaired. This lightwill also comeon during a malfunction in one of two ways: 0 SERVICE ENGINE SOON This system is called OBD I1 (On-Board Diagnostics-Second Generation) and is intended to assure that emissions are at acceptable levels for the life of the vehicle, helping to produce a cleaner environment. (In Canada, OBD I1 is replaced by Enhanced Diagnostics.) The SERVICE ENGINE SOON light comes on toindicate that there is a problem and service is required. Malfunctions often will be indicated by the system before any problem is apparent. This may prevent more serious damage to yourvehicle. This system is also designed to assist your service technician in correctly diagnosing any malfunction. Light Flashing -- A misfire condition has been detected. A misfire increases vehicle emissions and may damage theemission control system on your vehicle. Dealer or qualified service center diagnosis and service is required. Light On Steady -- An emission control system malfunction has beendetected on your vehicle. Dealer or qualifiedservice center diagnosis and service may be required. 0 2-69