Using the 9 modes of Global OBDII in diagnostics

Each shop I’ve ever worked in, from dealer to independent, has offered Check Engine Light diagnosis as
a part of its basic menu of services. Thanks to on-board diagnostics (OBDII) standards, each scan I used tool had
access to the same information regardless of the nameplate on the car, using the Global OBDII selection on the
tool’s menu. Let’s look at each mode scan tools display.