General Information
Tools used for troubleshooting and diagnostics are divided into two different types, tools for Off Board Diagnostic (diagnostics outside the vehicle) or On Board Diagnostic (diagnostics system in the vehicle) where the control module's diagnosis is used.
There are several tools used for Off Board Diagnostics, a few intended for diagnosis of a control module and its systems are mentioned in this document.
There are control modules with integrated diagnosis, where read-out of diagnosis only is possible with a built-in "tool". This applies to, e. g., climate control module MCC where read-out takes place via light-emitting diode on the front of the panel. For, e. g., audio unit HU 1205, the audio unit is not connected to the diagnostics socket in the vehicle. All diagnostics as well as other settings are controlled directly by menus in the display.