As auto manufacturers continue to use more and more technology in their vehicles, electrical systems become more and more complex and thus more difficult to diagnose issues or concerns. With the introduction of CAN-Bus systems running on a complicated electrical and fiber-optic network of modules and system, electrical diagnosis is not as straightforward as it once used to be. How does a passenger door handle cause a DSC light on a 2009 750li? How can a wheel speed sensor cause a Check Engine Light on a 2002 325xi? Without the appropriate factory BMW training and years of experience, these issues and many of them would be near impossible to diagnose, especially without using factory diagnostic software.