1994 GMC Suburban Owner's Manual - Page 342

GASOLINE ENGINES WITH LIGHT DUTY EMISSIONS - MAINTENANCE SCHEDULEltf * An Emission Control Service ** See "Explanation of Scheduled Maintenance Services" in the Index. $ The California Air Resources Board has determined that the failure to perform this maintenance item will not nullify the emission warranty or limit recall liability prior to the completion of vehicle useful life. General Motors, however, urges that all recommended maintenance services be performed at the indicated intervals and the maintenance be recorded. t To determine the emissions classification of your engine, refer to "Selecting the Proper Maintenance Chart" inthis section. T0403/T0903 7-8