1993 GMC Suburban Owner's Manual - Page 311

. . -...-. ...a. . To helppreventdamage to yourexhaustsystem, yourvehicle if you notice: 0 do not continuetodrive Engine misfiring Loss of performance Otherunusualoperatingconditions and exhaustsystemservicedregularly. Q Q) Haveyourengine Three-Way Catalytic Converter Your vehicle'sthree-waycatalyticconverter is designedtoreducethe pollutants in yourvehicle'sexhaust.Useonlyunleadedfuel in yourvehicle. If youuse leaded fuel,you could damageyourthree-waycatalyticconverter, and otherenginecomponents. Computer Command Contrd System This system has anoxygen (OS) sensorthathelpskeepyourengine's air-fuel mixtureataproperlevel.Useonlyunleaded fuel in yourvehicle. If you use leaded fuel,you could damageyouroxygen (OS) sensorand three-way catalytic converter. TheMalfunction indicator Lamp (SERVICE ENGINE SOQN) on your instrument panel lets you knowwhenyouremissioncontrolsystemneeds service. The light will come on brieflywhen you startyourenginetoletyou knowthatthesystem is working. If it doesnotcomeonwhenyoustartyour engine,or if it comeson and stays on whileyou'redrivingyoursystemmay need service. Your vehicle should still be driveable,butyoushouldhaveyour systemservicedright away. Secondary Air hection (AIR) System You mayhave this system. it lets youknow if yourengine control module, wiringharnessorsolenoid need service. tf theMalfunctionIndicatorLamp (Service Engine Soon) comeson, you need service. 6-45