OEM parts categories for 2003 Audi A4: A/C & Heating (A/C & Heater Control Units, A/C Condenser, Compressor & Lines, A/C Evaporator & Heater Components, Air Conditioner, Automatic Temperature Controls, Blower Motor & Fan, Heater Core & Control Valve, HVAC Case, Switches & Sensors) | Air & Fuel Delivery (Air Inlet Controls, Air Intake, Cruise Control System, Fuel Injection, Fuel Supply, Fuel System Components, Intake Manifold, Intercooler, Throttle Body, Turbocharger) | Belts & Cooling (Belts & Pulleys, Cooling System, Radiator, Water Pump, Cooling Fan, Intercooler, Radiator & Components, Radiator Support, Splash Shields, Water Pump) | Body & Hardware (Center Pillar & Rocker, Hinge Pillar, Cluster & Switches, Console, Cowl, Door & Components, Ducts, Fender & Components, Frame & Components - Convertible Top, Front Bumper, Front Door, Front Door Glass & Hardware, Front Seat Components, Fuel Door, Gate & Hardware, Glass - Door, Glass - Lift Gate, Glass & Hardware - Back Glass, Glass & Hardware - Quarter Panel, Glass, Reveal Moldings, Glove Box, Grille & Components, Hinge Pillar, Hood & Components, Information Labels, Inner Structure - Quarter Panel, Instrument Panel, Lift Gate, Lock & Hardware, Motor & Components, Outside Mirrors, Pillars, Rocker & Floor - Floor & Rails, Quarter Panel - Glass & Hardware, Quarter Panel & Components, Quarter Window, Radiator Support, Rear Body, Rear Body - Floor & Rails, Rear Bumper & Components, Rear Door, Rear Floor & Rails, Rear Seat Components, Roof & Components, Seat Belt, Sound System, Splash Shields, Stowage Compartment, Structural Components & Rails, Sunroof, Top Cover & Components, Tracks & Components, Trunk, Trunk Lid & Components, Windshield Glass, Reveal Moldings, Windshield Header & Components, Wiper & Washer Components) | Brakes (Anti-Lock Brakes, Brake Components, Front Brakes, Hydraulic System, Parking Brake, Rear Brakes, Stability Control) | Charging & Starting (Alternator, Battery, Starter) | Driveline & Axles (Front Axle Shafts & Joints, Drive Axles, Rear Axle, Axle Shafts & Joints, Differential, Drive Axles, Propeller Shaft) | Electrical (ABS Components, Air Bag Components, Alarm System, Antenna & Radio, Anti-Theft Components, Convertible Top, Door & Components, Electrical Components, Front Door, Front Seat Belts, Fuel Door, Fuse & Relay, Heated Seats, Horn, Ignition Lock, Ignition System, Instruments & Gauges, Lift Gate, Mirrors, Navigation System, Power Seats, Powertrain Control, Rear Door, Rear Seat Belts, Senders, Starter, Sunroof, Switches, Trunk, Washer Components, Wiper & Washer Components) | Emission Control & Exhaust (A.I.R. System, EGR System, Emission Components, Exhaust Components, Exhaust Manifold) | Engine (Engine & Trans Mounting, Engine Appearance Cover, Engine Parts, Mounts, Cylinder Head & Valves, Camshaft & Timing, Variable Valve Timing, Oil Cooler, Oil Pan, Oil Pump, Crankshaft & Bearings, Pistons, Rings & Bearings, Transaxle Parts, Turbocharger & Components) | Headlights & Lighting (Bulbs, Fog Lamps, Headlamps, Headlamp Washers/Wipers, High Mount Lamps, License Lamps, Side Repeater Lamps, Tail Lamps) | Interior & Exterior Trim (Covers & Trim - Top, Exterior Trim - Door, Exterior Trim - Fender, Exterior Trim - Front Door, Exterior Trim - Lift Gate, Exterior Trim - Pillars, Rocker & Floor, Exterior Trim - Quarter Panel, Exterior Trim - Rear Door, Exterior Trim - Roof, Exterior Trim - Trunk, Exterior Trim - Trunk Lid, Interior Trim - Convertible Top, Interior Trim - Door, Interior Trim - Front Door, Interior Trim - Lift Gate, Interior Trim - Pillars, Rocker & Floor, Interior Trim - Quarter Panels, Interior Trim - Rear Body, Interior Trim - Rear Door, Interior Trim - Roof, Interior Trim - Trunk, Interior Trim - Trunk Lid) | Maintenance & Lubrication (Automatic Transmission, Belts & Pulleys, Filters) | Steering (P/S Pump & Hoses, Steering Gear & Linkage, Steering Column & Wheel, Steering Gear & Linkage, Shroud, Switches & Levers) | Suspension (Axle & Differential - Rear, Drive Axles - Front, Drive Axles - Rear, Front Suspension Components, Lower Control Arm, Stabilizer Bar, Rear Suspension Components, Lower Control Arm, Upper Control Arm, Stabilizer Bar, Shocks & Components - Rear, Stabilizer Bar & Components - Front, Struts & Components - Front, Suspension Mounting - Front, Wheels, Covers & Trim) | Transmission (Automatic Transmission, Clutch & Flywheel, Gear Shift Control - AT, Gear Shift Control - MT, Hydraulic System, Manual Transmission)