If you are looking for code procedures, charts and fault remedy
diagnoses, you will find nil in the Benz 124CD.
But for $20, you can get a model specific one from P.Mechanics that has all codes and procedure [including codes for the other systems at the different sockets in the diagnostic box that are not accessible with the built-in led, but are with a $5 hand made led *tool]. * see archives *
Between both Cds , you are there.....
But for codes , this is the way to go for the DIYer