...OBD and passed Emission? I have a 1996 Mercedes Benz failed smong test due to OBD (On Board Diagnostic) and passed emission. We replaced the O2 sensor and still failed, no failure codes detected when plugged to the OBD2 handheld device. Does anyone ever experienced this problem? Please help!!!

Please do not take this as gospel. A friend of mine had the same car. Did the same thing. Finally after several visits to the dealership they called in a factory tech from New Jersey. Seems there was some sort of corrosion on the terminals of one of the computers and when that was cleaned the car performed correctly. Something about low voltage cause by resistance of the corrosion.

Have a dealer check all the service bulletins for this problem that is where the factory tech got the fix

At least this is what my friend told me.