White plug with a rubber boot on it. Jump the pins above (note orientation of plug, key up)
Turn on the ignition (no need to start engine) and codes will display on speedometer LCD.
When you look into the odometer box and see the code, e.g. C46 (EXCVA – exhaust control valve), just to the left of the code will be a hash mark. That represents the position of the throttle open percentage/position. If you then open up your throttle, the hash mark will move up screen to represent the increasing open position of the throttle. If it is moving appropriately, that is supposed to mean that your throttle is working ok.