This was more a year of waiting than one of major changes. All Cadillac engines were now fuel injected. All but Cimarron and Fleetwood limousines carried the HT-4100 cu. in. (4.1 liter V-8 with aluminum alloy block and digital fuel injection. This year, that 249 cu. in. engine gained a new exhaust system and catalytic converter, plus revised calibration settings, to meet high-altitude emissions standards.
New features on DeVille, Fleetwood Brougham and limos included a goldtone horizontally-winged Cadillac crest ornament on front parking and turn signal lenses; new car-colored bodyside moldings; new goldtone vertically-winged Cadillac crest and goldtone accents on taillamp lenses; and new standard electronic level control. Diesel engine identification plaques were now on the left rear of the decklid. Faster-warming glow plugs went into the optional 5.7 liter diesel V-8, for improved cold-startups. A modified optional theft-deterrent system could detect any object on the driver's seat that weighed 40 pounds or more.
| All Cadillacs again had a 17-symbol Vehicle Identification Number (VIN), stamped on a metal tag attached to the upper left surface of the cowl, visible through the windshield. |
| Some of the coding changed this year. |
| The first character is a "1" to indicate the manufacturing country (U.S.A.) |
| Next is a "G" for General Motors |
| The third character is a "6" for Cadillac Division. |
| The next character indicates restraint system: "A" manual; "B" automatic. |
Symbol five denotes car line and series:
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Characters six and seven indicate body type:
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Next comes the engine code:
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| The ninth character is a check digit. |
| Character ten indicates model year ("E" 1984). |
| Character eleven denotes the assembly plant. |
| The last six characters is a six-digit production sequence number. |
| As before, engines carried an identifying number and bodies held a number plate. |
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