Hi, I'm new to this forum. I'd like some advice on making the O2 sensor warning light on the instrument panel turn off. The car at issue is a 1993 190E 2.3 automatic; this car is a "California emission" car. I was able to reset the warning light by pressing a button on a box in the passenger's foot well; however, a few seconds after the reset switch is pressed, the warning light would blink 7 times, pause, blink 6 times, pause, and stay on. The warning light comes right back on the next time I start the car. I've replaced the O2 sensor with a Mustang sensor and checked the air-fuel mixture. The voltage from the O2 sensor fluctuates from 0.2 volts to 0.8 volts. The X-11 pin 3 fluctuates at about 50% duty cycle. Thus, the O2 sensor and the air-fuel mixture appear to be good. Just today, I replaced the OVP relay out of desperation, but it didn't help. Now, I don't know what else to do. The car seems to drive fine, but I'd really like to make the light stay turned off. If something is faulty, I'll like to get it fix because something like this might affect gas mileage and I don't need to burn more gas than necessary--this little Benz requires expensive Premium gas. Thanks. Look forward to suggestions.

By the way, spark plugs, cap, and rotor were recently replaced--after the O2 sensor light problem. The ABS warning light is also On all the time, but I don't really care about ABS and unplugged the ABS computer completely.