What does the ECM control? on 2005 Volvo XC90

I took my car in for an air conditioning problem,and the ECM was diagnosed as the problem. What other electrical components and features will be affected by a faulty ECM?

Asked by for the 2005 Volvo XC90
The ECM controls many things, but primarily the fuel injection and ignition systems. It also controls the A/C compressor. When these computers fail, it may only effect 1 thing, so you probably wont see other systems acting up.
Thanks much. Appreciate the quick response.