- O -

O

Orange.

O-ring

A round ring having a square or round cross section used as a seal, such as at the end of a hydraulic line.

O.d.

An abbreviation for outside diameter.

O.H.

An abbrevation for Over Hall. It may apply to any component with more than one part that expereances ware.

O/D

Overdrive.

O/L

Open loop.

O2

Oxygen sensor.

O2 Sensor

A term used for oxygen sensor.

O3

Ozone.

OAH

An abbreviation for overall height.

OAI

Outside air induction.

OAL

An abbreviation for overall length.

OASIS

An acronym for On-Line Automotive Service Information System.

OAT

An Acronym for Organic Acid Technology compounds used in long life antifreeze to replace nitrates and phosphates or silicates as a corrosion inhibitor.

OAW

An abbreviation for overall width.

OBD

An abbreviation for on-board diagnostics.

OBD-I

An abbreviation for On-Board Diagnostics Generation One. An on-board automotive diagnostic system required by the California Air Resources Board since 1988, which uses a microprocessor and sensors to monitor and control various engine driveability functions.

OBD-II

An abbreviation for On-Board Diagnostics Generation Two. OBD-II expands upon OBD-I to include emissions system and sensor deterioration monitoring.

OBDII Monitors

Eather a passive, active, or intrusive test run by the diagnostic management system after the enable criteria has been compleeted.

Observed Horsepower

The brake output of an engine as observed on a dynamometer.