Bruno, there's three types. .
The MB fault system is: ACTIVE, REGISTERED and STORED.
An ACTIVE fault is one that is currently occurring while the car is running at idle or at speed. They represent components currently failing. These codes cannot be erased and are only meaningful with the ignition on and the engine running. An example is: "bad crankshaft sensor". This fault will immediately turn on the CE light.
A REGISTERED (also called PENDING) fault is one that has exceeded the preset number of times (2x) and is stored in temporary memory. When the fault occurs consistently and exceeds another preset number, it is moved to PERMANENT (also called STORED) storage and the CE light is illuminated. These faults are stored in the carts system controller in its permanent memory. Clearing these (and REGISTERED) faults will turn of the CE light.
You may want to ignore a REGISTERED fault but a STORED fault really means that something is not right! Also a ACTIVE fault may indicate a bad connection rather than an actual fault. For example, a loose gas cap (only in later model MBs).
Read my page for more general info on DTC. Click www house below.
Regards . . . . JimF
'94 S500 Cpe
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