The luxury automaker BMW has issued two recalls involving about one million cars and sport utility vehicles that are at risk of catching fire even when they are not in use.

The first recall covers more than 672,000 cars. It includes several BMW 3 Series models from 2006-11 with wiring and electrical conductors in the climate control system that are vulnerable to overheating, BMW told the National Highway Transportation Safety Administration on Thursday.

The second, larger recall involves the 2008-11 128i and various other 2007-11 models with six-cylinder engines, such as the 328i and the 525i. In these vehicles, the heater designed to keep the positive crankcase ventilation from freezing has the potential to short-circuit, causing the parts inside its valve to melt. The crankcase ventilation system helps gases escape from an internal combustion engine.