square headlamps in place of the recessed circular units, whilst the sedans received new wraparound rear lamp clusters and a restyled leading edge to the trunk lid, although the rear of the wagons remained unchanged. The GLE was added while the L was cancelled, and the six-cylinder diesel arrived late in the year. For 1980, the sporty GLT arrived, replacing the GT. For 1981 there was yet another new grille, while the station wagons received new, wraparound taillights. The B21A gained some four horsepower, now , while the carburetted B23A with was introduced in some markets. The Turbo arrived, while six-cylinder models now had a more powerful 2.8-liter engine. 1981 also saw the dashboard altered significantly, which a much larger binnacle in order to bring the radio and clock within the driver's line of sight. The instrument pod itself, which had been unaltered since the 1973 model year 100 Series, was also redesigned. Incremental improvements were made almost every year of the production run. One of the major improvements was the introduction of the oxygen sensor in North America in late 1976 (1977 models), which Volvo called Lambda Sond and developed in conjunction with Bosch. It added a feedback loop to the K-Jetronic fuel injection system already in use, which allowed fine-tuning of the air and fuel mixture and therefore produced superior emissions, drivability and fuel economy. For the 1983 model year, Volvo dropped the DL and GLE labels, selling the cars simply as 240s. In the domestic Swedish market, the 240 could be had with a 2.1 or 2.3-liter engine (more options were available in export), but the bigger engine always came coupled with a five-speed transmission and tinted windows. The 1983s also received wider side trim and all models had the larger taillights introduced on the previous year's GLT model. A B23E-engined GLE variant was also added (not available with two doors). Buyers protested against the lack of grades and they returned for 1984. A new manual gearbox also arrived for 1984, while a four-speed automatic option was available in the GL. The GLT and Turbo versions received a taller grille. About one-third of all 240s sold were station wagons, which featured very large cargo space of . They could be outfitted with a rear-facing foldable jumpseat in the passenger area, making the wagon a seven-passenger vehicle. The jumpseat came with three-point seat belts, and wagons were designed