This glossary was compiled by Don B at jaguarforums.com and is reproduced here
with his permission
L = Liter or Litre, unit of volume or displacement, 1 L = 1.05669 qt. or 61.0237 cubic inches
L = Long Wheel Base as in XJ8L (LWB)
L/100km = Litres Per 100 Kilometers, a measure of fuel economy (see mpg, kmpl)
Lag = Delay in response to an input, such as Fuel Injector Lag
Lambda (λ) = Air-Fuel Equivalence Ratio = AFR/Stoichiometric AFR (for gasoline/petrol 1λ = 14.7:1)
Lambda Sensor = Oxygen Sensor (O2, O2S, HO2, HO2S)
Lambswool = Fleece, as used in OE and aftermarket Jaguar rugs or overmats
Lawson, Geoff = Jaguar Design Director 1989-1999 (XJ220, X300, XK8, S-Type, X-Type)
lb. = Pound, unit of weight, 1 pound = 0.453592 kilogram
lb. ft. or lb·ft = Pound-Feet, unit of torque (ft. lb., ft·lb, Foot-Pounds, Nm, N·m, Newton-metre)
LCD = Liquid Crystal Display
LCEI = Lucas Constant-Energy Ignition, ignition system employed on Jaguar V12 engines (LCEI)
LCM = Level Control Module (ADHLS), Lamp Control Module or Lighting Control Module
Lead Substitute = Added to unleaded fuel to reduce valve seat wear in engines designed for leaded fuel
Lean = AFR with too much air and/or too little fuel, Lambda (λ) > 1 (see Rich)
Leaper = The Jaguar leaping cat trademark, especially in hood/bonnet ornament form
LED = Light-Emitting Diode
Leyland Motor Corp. = LMC, merged with BMH in 1968 to form British Leyland (w.s.)
LFRT = Long-Fiber Reinforced Thermoplastic, used in many Jaguar parts (Celstran)
LGF = Long Glass Fiber (used to reinforce plastics, see Fibremod, Borealis and Borouge)
LH = Left Hand, Left Hand Side, typically referenced from the driver’s seat facing forward
LHD = Left Hand Drive
LHIMT = Left-Hand Intake Manifold Tuning Valve, (see IMT, RHIMT)
LHLCM = Left Hand Level Control Module (ADHLS L)
LHM = Limp Home Mode, permits driving while reducing risk of engine or transmission damage (RP)
LHUD = Laser Head-Up Display (see ARHUD, HUD)
LHS = Left Hand Side, typically referenced from the driver’s seat facing forward
License Plate = Number Plate
Limp Home Mode = Restricted performance, impaired transmission function due to a fault (LHM, RP)
Limp Mode = Limp Home Mode
Liter / Litre = L or l, unit of volume, 1 L = 1.05669 qt.
LKA = Lane-Keeping Assistance (see ADAS, Mobileye, Gentex)
LKAS = Lane-Keeping Assistance and Support (see ADAS, Mobileye, Gentex)
Lock Washer = Spring Washer, Helical Spring Lock Washer
LONGFT = Long Term Fuel Trim (FTLT, LTFT)
Loom = Wiring Harness, Harness
Lorry = Truck
LPG = Liquefied Petroleum Gas or Liquid Petroleum Gas
LSD = Limited-Slip Differential
LTAI = Long Term Adaptive Idle (see also STAI)
LTFT = Long Term Fuel Trim (FTLT, LONGFT)
LTI = Long Term Idle adaptation (see STI)
Lug Nut = Wheel Nut
LUMP = “Less Upkeep More Power,” slogan of Chevy engine conversion advocates
Luxan = Dye-enhanced-grain grade of Connolly Vaumol leather (see Autolux, Autocalf)
LW = Long Waveband (see MW)
LWB = Long Wheel Base, indicated by “L” in model name, such as XJ6L (see SWB, WB)
Lyons, Sir William = “Mr. Jaguar,” co-founder of Jaguar Cars with William Walmsley