Following are vacuum diagrams for most of the engine and emissions package combinations covered in this guide. Because vacuum circuits will vary based on various engine and vehicle options, always refer first to the vehicle emission control information label, if present. Should the label be missing, or should vehicle be equipped with a different engine from the vehicle's original equipment, refer to the diagrams below for the same or similar configuration.
If you wish to obtain a replacement emissions label, most manufacturers make the labels available for purchase. The labels can usually be ordered from a local dealer.
The following is an assortment of vehicle emission control information labels. If the label on your vehicle differs from what is listed here, always follow what is on your underhood sticker, as it is most likely the accurate label for your particular engine application.
Fig. Example of the Vehicle Emissions Control Information (VECI) label in the engine compartment
Fig. Vacuum hose routing diagram-1990 Deville, Fleetwood, Eldorado and Seville
Fig. Vacuum hose routing diagram-1991-93 Deville and Fleetwood
Fig. Vacuum hose routing diagram-1991-93 Eldorado and Seville with the 4.9L engine
Fig. Vacuum hose routing diagram-1993-95 Eldorado and Seville with the 4.6L engine; 1994-95 Deville Concours
Fig. Vacuum hose routing diagram-1994-95 Deville and 1994 Eldorado with the 4.9L engine
Fig. Vacuum hose routing diagram-1996-98 Deville, Deville Concours, and Eldorado
Fig. Vacuum hose routing diagram-1996-98 Seville
Fig. Vacuum hose routing diagram-1997-98 Catera