Although the original contract with Jensen called for 10,000 units, Volvo opted to cease working with the latter due to quality control problems. At this point, around 6,000 cars had been built. In 1963, Volvo decided to move all production to Sweden and the car was renamed the P1800S, with S standing for Sweden. Power output was also increased at this time and in 1969 the original engine was replaced with a 2.0-liter unit. In 1970, the P1800E was introduced and it featured a new fuel injection system. The 1800ES came out in 1972 and unlike previous versions, this one had a shooting-brake body style.