Automotive Terms And Abbreviations- O

O2- Oxygen
O2S- Oxygen Sensor
OBD- On-Board Diagnostics
OBD II- On-Board Diagnostics Second Generation
OC- Oxidation Converter Catalytic
OD- Outside Diameter
ODM- Output Drive Module
ODO- Odometer
OE- Original Equipment
OEM- Original Equipment Manufacturer
OHC- Overhead Camshaft
ohms- Ohm
OL- Open Loop, Out of Limits
ORC- Oxidation Reduction Converter Catalytic
ORN- Orange
ORVR- On-Board Refueling Vapor Recovery
OSS- Output Shaft Speed
oz- Ounce(s)