Have a 1995 S500 (140.051) equipped with a 119.970 motor (LH-SFI) and a build date of March 30,1995. The electronics bay at the right rear of the engine compartment has a small red LED display and pushbutton located external and adjacent to the housing containing the control units.

Is this device an integral code reader and, if so, how is the system accessed?

The LED illuminates if the ignition is energized and the pushbutton is depressed but I am unable to initiate any LED blinking for a fault code check.

Thanks.