What do these codes mean?

For VSC vehicle stability control ...o2 sensor b1 s2 this is oxygen sensor 2 on cylinder 1 side..for vehicle speed sensor that's mounted on transmission

P0136 LEXUS - HO2S12 Circuit Malfunction...Possible causes: Faulty Rear Heated Oxygen Sensor Bank 1, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted, Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection, Inappropriate fuel pressure, Faulty fuel injectors, Intake air leaks, Exhaust gas leaks...Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem. It takes more time for the sensor to respond between rich and lean than the specified time. Possible symptoms: Engine Light ON (or Service Engine Soon Warning Light), High Fuel Consumption, Excessive Smoke from Exhaust.......P0500 LEXUS - Vehicle Speed Sensor 'A'...Possible causes: Faulty Vehicle Speed Sensor, Vehicle speed sensor harness or connectors is open or shorted, Vehicle speed sensor circuit poor electrical connection, Faulty Engine Control Module (ECM). Tech notes: Replaced the speed sensor on top transmission...When the code is detected the almost 0 km/h (0 MPH) signal from vehicle speed sensor is sent to ECM even when vehicle is being driven. Possible symptoms: Engine Light ON (or Service Engine Soon Warning Light), Speedometer may not work properly, Transmission shifting problem.