GMC 1994 Yukon Owner's Manual page 342

GASOLINE ENGINES WITH LIGHT DUTY EMISSIONS
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MAINTENANCE SCHEDULE ltf
*
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" in this section.
T0403/T0903
7-8