O – Jaguar Abbreviations, Acronyms and Terms

This glossary was compiled by Don B at jaguarforums.com and is reproduced here
with his permission

O2 = Oxygen, at STP, two atoms bind to form dioxygen, with the chemical formula O2
O2S = Oxygen Sensor (O2, HO2, HO2S, Lambda Sensor)
O2S, Narrowband = Older sensor that responds to narrow AFR range, Lean/Stoic/Rich
O2S, Wideband = Newer sensor that responds to wide AFR range and eliminates lean-rich cycling
OBD = On Board Diagnostics
OBD I = On Board Diagnostics, first generation CARB standards, implemented on Jaguars 1991-’94
OBD II = On Board Diagnostics, second generation CARB standards, implemented on Jags from 1995
OBTW = “Oh, By The Way” (BTW)
O/C = Open Circuit
OCC = Oil Catch Can
OCS = Occupant Classification System
OCSCM = Occupant Classification Sensor Control Module (seat weight sensor)
OD or O.D. = Outside Diameter (see ID)
O/D or OD = Overdrive
ODO = Odometer, milometer or mileometer
Odometer = Milometer or mileometer (ODO)
ODST= On Demand Self Test (a function in IDS, WDS or SDD)
OE = Original Equipment, part or component fitted to new vehicles at Jaguar factory
OEM = Original Equipment Manufacturer/Manufacture, may be Jaguar or a third party vendor
OFC = Overrun Fuel Cutoff, ECM cancellation of fuel injection during engine overrun conditions
Off Ramp = Exit Ramp, Slip road leaving a motorway
Off Side = Passenger Side (OS, PS), see Near Side
OHC = Overhead-cam, design used on Jaguar engines, see SOHC, DOHC, OHV
OHV = Overhead-valve engine design, see OHC
Oil Pan = Sump
OL = Open Loop, ECM controlling fueling based on stored maps rather than O2S feedback (see CL)
On Ramp = Entrance Ramp, Slip Road entering a motorway
On Time = Duration of fuel injector opening, controlled by ECM (IPD, Pulsewidth, Pulse Width)
On-Plug Ignition Coil = Each spark plug is fitted with its own ignition coil (COP)
OP = Original Poster or Post in a forum thread
Open Loop = ECM controlling engine by stored fueling maps rather than O2S feedback (OL) (see CL)
OPUS = Oscillating Pick-Up System, Lucas ignition system employed on Jaguar V12 engines
ORVR = On-Board Refueling Vapor/Vapour Recovery (part of the X308 EVAP system)
OS = Off Side, passenger side (see Near Side), or Oxygen Sensor
OSH = Oxygen Sensor Heater
OSS = Occupancy Sensing System
OT = “Off Topic;” Oil Temperature or Oil Temperature Sensor (EOT, EOTS, OTS)
OTS = Oil Temperature Sensor (EOT, EOTS, OT); Other Than Sedan; Open Two-Seater
Otto Cycle = 4-stroke thermodynamic cycle used in most gas/petrol auto engines (see Diesel Cycle)
Overmat = Footwell rug or carpet mat
Overpass = Flyover
Overrider or Over Rider = Projection mounted to bumper to prevent interlocking with another vehicle
OZRA = Upgraded version of GM400 automatic transmission used in Jaguar XJR-S