The first generation Jaguar XJ Series was numbered the XJ6 and was launched in 1968. It derived its power from a choice of two engines - a 2.8 Liter or a 4.2 Liter. The XJ version was also sold by Daimler under the brand name Daimler Sovereign. In 1972, a XJ 12 version of the Jaguar XJ Series was launched with a 5.3 Liter V12 engine. The second generation XJ Series was launched in 1973 with a 3.4 Liter engine and the XJ 12 version was continued. The XJ Series also became available as a coupe. The second generation cars were built with a bigger body but small grille. In 1975, a two door coupe model was introduced which was called the XJC. It was a shorter version of the XJ model introduced in 1973. In 1979, the third generation XJ Series was introduced. The new car was powered by a 5.3 Liter V 12, 4.2 Liter or 3.4 Liter engine. The first two engines had a fuel injection system manufactured by Bosch. Also available under the Daimler brand name were four models titled the Daimler Sovereign, the Daimler Vanden Plas, the Daimler Double Six and the Daimler Double Six Vanden Plas. In 1982, the Interiors of the XJ Series were given a change with a computer being introduced on the V12 models. In 1983, the Sovereign brand name being used by Daimler was transferred to Jaguar and the Jaguar Sovereign came into the market.
In 1988, the fourth generation XJ Series was introduced. The car was numbered the XJ 140 and it came with two engines having six cylinders. There was a 2.9 liter engine that was only available in Europe and a 3.6 Liter engine. The XJ 12 was still available with a V12 engine. In 1989, the XJ 40 was introduced. It came with two engines - a 3.2 Liter and a 4.0 Liter engine. In 1994, an airbag on the passenger's side was introduced. In 1995, the XJ 140 got a new design and new numbering. It was now called the XJ300 and it got a supercharged engine. In 1997, the fifth generation XJ Series was introduced and it came in four models that were all rear-wheel drive. The entry level model was powered by a 4.0 liter V8 engine, which also powered the Vanden Plas Series. A V12 engine powered the XJR and XJ 12 models, which were equipped with traction control. In 1996, legroom at the back was increased in the Vanden Plas and XJ12 models. 1n 1997, all engines got six cylinders and the V12 engine was taken out. In 1998, the XJ Series got airbags in the side for passengers seated in the front and new V8 engines were introduced. In 2000, a luxury model of the Vanden Plas was introduced with a navigation system. In 2001, the XJ Series got a system that warned the driver when reversing if something was obstructing their view, while the XJR got a back seat that was heated and the Vanden Plas came with all heated seats. In 2002, a sport model and XJ100 were introduced.
In 2004, the sixth generation XJ Series debuted with just one body type. It came in three versions - entry level, Vanden Plas and XJR. All three models derived their power from a 4.2 Liter V8 engine and an automatic gear system having six gears. A longer body XJ Series was introduced in 2005 that came in three versions- the XJ8L, the Super V8, and the Vanden Plas. In 2006, the XJ Series got new styling in the front and a new model titled the Super 8 Portfolio was launched. The new portfolio had a better inside and outside look and came with 20 inch tires.