1998 Chevrolet Blazer Owner's Manual - Page 147

Malfunction Indicator Lamp (Service Engir light) NOTICE: If you keep driving your vehicle with this light on, aftera while, your emission controls may not work as well, your fuel economy may not as be good and your engine may not run smoothly. as This could lead costly repairs that 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 ison and the engine is not running. If the light doesn't come on, have repaired. it This light will also come on during a malfunction in one of two ways: 0 SERVICE ENGINE SOON Your vehicle is equipped with a computer which monitors operation of the fuel, ignition and emission control systems. 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 produce a cleaner to environment. The SERVICE ENGINE SOON light comes on to indicate that there is a problem andservice is required. Malfunctions often will indicated by be the system beforeany problem is apparent. This may prevent more serious damage to your vehicle. 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 on may damage the emission control system your vehicle. Dealer or qualified service center diagnosis and service maybe required. Light On Steady -- An emission control system malfunction has been detected on your vehicle. Dealer or qualified service center diagnosis and service may be required. 0 2-73