 Accordingly, the car's on-board computer was modified from dealing only with the engine as in 1993 (ECM), to controlling both the engine and transmission on automatic models (PCM).The computer in 1993 was run via Speed Density system, which measured engine speed (RpM) and load (MAP in kPa) to compute airflow requirements and then use that against the VE (Volumetric Efficiency) table to get the proper readings in order to warn the driver about refuelling.An IAT (Intake Air Temperature sensor) was also used as air density changes with temperature.