Don’t know what your fault code number is but code P0150 is related to Oxygen Sensor 1 form Bank 2. I replaced mine last December. It took me 15 minutes to replace both sensors (front right and left). You must have the right tools to do the job and they are relative inexpensive and you can get them from any auto parts store (AutoZone, Advance Auto Parts, PepBoys, etc). Tools you need are: (1) Oxygen Sensor or Vacuum Socket (around $10) and (2) At least a 15-in extension bar for a 3/8-in drive. You may put several extension bars to meet that length (I bought my 10â€? extension at a Big!Lots store for $2.49). If you are not as familiar with the W210 engine as me, locating the right O2 sensor is a challenge. No sweat, under the hood and on the driver side, locate the black cap for the brake fluid reservoir and a letter Z of the Benz on the engine’s cosmetics cover. Draw a straight imaginary line between the black cap and letter Z, you will see a narrow cavity between the engine block and insulated firewall. Identify the round-blue wire (don’t know if it comes with a different color but mine was blue) for the sensor. Unplug the connector (using a small flat screwdriver tip to lift its notch and pull it out); trace the wire to the other end to locate the sensor at the bottom-left of the engine (this is why you need an extension bar to take the sensor off). My trick to install the sensor is holding the tip of the O2 wire (without O2 socket) and drop the sensor into the screw hole then slowly twist the wire clockwise a few turns to make sure the sensor is screwed on correctly. Pay attention when using the O2 socket so it won’t strip and cut the wire.
I searched the internet and found that Autohuasaz.com offers the best price for O2 ($73.07). Part for Oxygen 1 (left side) is 0258003642009. I also replaced the sensor from the right (part # 0258003798009) and of course they are from Bosch.
