Battery may be a BAD idea if there's a pushbutton/LED combo switch under the hood. Yes, it will reset the DTC but it also resets the radio codes in my C140. Don't know about W202s.

I personally have not looked at the 202 to know but if there is one check my page (red house) for what to do. Menu item #5 is the Diag Module.

Yes, you should see what the code is before resetting it.

__________________
Regards . . . . JimF
-------------------
'94 S500 Cpe

Visit my Mercedes Web Page