Well the E-S-M switch is pretty straight forward. In E, Econmy mode the car goes through all gears and ends up in Overdrive. In S (sport) the shift points are raised to give quicker acceleration. In M, Manual, you select the gear (1-2-3). Sliding the E-S-M switch will change modes and the mode will appear on your instrument cluster. If in any mode except E, pushing the depression in the center of the switch will take you back to E. The oxygen sensors are located in the catalytic convertors (they screw in) and you will need to drop the forward part of the exhaust system to access the sensors.