'93 190e 2.3 119K. the dash indicator lamp "O2 Sensor" is ON steady, "check engine" lamp is off. with ignition on and engine running or not running, i press the reset button on the O2 control box for 3 secs (control box located on passenger side interior foot well). indicator lamp goes out for a count of 10 or so, then blinks 6 times, then a pause, then a single blink, then pause, then ON steady. this is repeatable. according to one of the shop manuals i have, the "O2 Sensor" lamp should turn on every 60K miles indicating time for service/replacement of the )2 sensor. i replaced the O2 sensor about 10K ago after the check engine lamp came on (O2 Sensor lamp off) and i read the on board blink codes at the underhood diag connector. after replacing O2 sensor, all was well until now.

anyone know what the "O2 Sensor" lamp blink codes are?

ONLY on California version cars!
MB made the O2 sensor replacement part of EVERY 60K servce in Calif.

Just remove the O2 sensor relay as most likely it is defective,

As far as blink codes go.....code 5 is for a O2 sensor that doesn't control the mixture

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thanks for the info, my 190e is a calif car. to be clear, is the blink code 5 you referred to from the OBD readout one gets from the diag connector under the hood rh side? the blink code 6 i get is from watching the dash warning lamp cluster "O2 Sensor" lamp immediately after doing an O2 Sensor Control Box rest via the button on top of the box.

i found a wiring diagram showing how the O2 Sensor Indicator Control Unit is used and MB Doc is correct, the unit does nothing but keep track of mileage and set the lamp every 60K miles or so on Calif cars. I removed the unit. could find nothing on blink codes for this unit. end of story i think. thanks to MB Doc