Time for a freshening-up. The first revisions to the XJ centred on comfort, with improvements to the heating and ventilation and a new air conditioning system, plus a restyle of the impressive-looking but ergonomically poor switchgear and facia. Safety was also an increasingly important consideration, so new disc brakes were fitted all round (ventilated up front), the doors featured side impact beams and a laminated windscreen became standard. Extra sound-deadening insulation was packed in, and a heated rear windscreen and central door locking came as standard too for the first time. There were also changes to the exterior, most noticeably a smaller radiator grille and higher-mounted bumpers, to meet the new American federal crash safety legislation which required that bumpers be positioned at broadly the same height.

The 2.8-litre engine was dropped, but that old 4.2-litre XK unit continued. Jaguar finally acknowledged the need for better fuel economy in 1975, introducing a 3.4-litre engine, developed from the 4.2. This came in conjunction with cloth upholstery and a stripped-out specification (no electric windows or central locking) and cost from £4,794. The V12 models also continued, including the long-wheelbase Daimler Vanden Plas Double Six, with an interior hand-finished by the Vanden Plas coachworks firm, still in Kingsbury, North London at that point. The LWB option was also available on the six- and Jaguar 12-cylinder models (XJ6L and XJ12 L). In an attempt to address the V12's thirst, and the upcoming exhaust emissions regulations in the States, a fuel-injected version of the V12 was introduced in 1975, which had a 285 bhp output and fuel consumption of a hardly more frugal 13.8 mpg.