O
OEM
Original equipment manufacturer, i.e., the manufacturer of a vehicle.
Office of Defects Investigation
An office within the National Highway Traffic Safety Administration that conducts defect investigations and administers safety recalls, and that monitors the adequacy of manufacturers' recall campaigns.
Off-road ready
A vehicle with high-ground-clearance outfitted for the rigors of traveling on non-paved roads.
Oil filter
A cartridge-filled canister placed in an engine's lubricating system to strain dirt and abrasive materials out of the oil.
On-board diagnosis system
A computer-controlled system that identifies malfunctioning or out-of-adjustment components under its control through the display of trouble codes. The presence of trouble codes is usually indicated by an intermittently or constantly lit "check engine " or "service engine soon" light.
115V AC Outlet
An electrical socket receiving 115v AC current produced by a vehicle's charging system.
One-touch windows
Vehicle windows with a changeover switch that is capable of automatically rolling the window glass completely up or down (as well as functioning as a conventional momentary power window switch).
Optional equipment
Equipment that is not included in the manufacturer's base configuration of a vehicle.
Overpressure safety switch
A switch used on a turbocharged engine that warns the operator of excessive and potentially harmful intake pressure that may be caused by component malfunction.
Oversteer
A handling characteristic of a vehicle that causes it to turn more sharply than the driver intends because the rear wheels are sliding to the outside of the turn.
Oxygen sensor
In a computer-controlled, fuel-injected vehicle, a sensor mounted in the exhaust stream that relays air/fuel ratio information to the fuel control computer that allows the computer to make adjustments.