Repair and Diagnosis

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• Quick Lookups
  • Common Specs & Procedures
    • Common Specifications & Procedures (Sedan)
  • DTC Index (A3 Sedan)
  • Electrical Component Locations
    • RS 3 - Component Locations
  • Fluids
  • Technical Bulletins
    • Safety Recalls
    • Technical Service Bulletins
  • Tire Fitment
  • Wiring Diagrams
    • OEM Connector End Views
    • Using lemon2025'S System Wiring Diagrams
• Accessories & Equipment
  • Anti-Theft Systems
    • Front Doors, Central Locking System -- (A3 Sedan)
    • Interior Lights, Lamps And Switches -- (A3 Sedan)
    • Interior Lights, Switches -- (A3 Sedan)
  • Body Interior
    • General, Technical Data - (Exterior) -- (A3 Sedan)
    • General, Technical Data - Body Interior -- (Sedan)
  • Collision/Avoidance
    • Driver Assistance Systems Front Camera
    • Driver Assistance Systems Front Camera Calibration
    • Lane Change Assistance System
    • Parallel Parking Assist System
    • Parking Aid System
    • Rearview Camera System (2017-19)
    • Wheels, Tires, Wheel Alignment (Suspension, Wheels, Steering) -- (A3 Sedan)
  • Cruise Control Systems
    • Adaptive Cruise Control (Acc) System Adjustment
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Start/Stop System)
    • Wheels, Tires, Wheel Alignment (Suspension, Wheels, Steering) -- (A3 Sedan)
  • Drivers Assistance Systems - ADAS
    • Driver Assistance Systems Front Camera
    • Driver Assistance Systems Front Camera Calibration
    • Lane Change Assistance System
    • Parallel Parking Assist System
    • Parking Aid System
    • Rearview Camera System (2017-19)
    • Wheels, Tires, Wheel Alignment (Suspension, Wheels, Steering) -- (A3 Sedan)
  • Entertainment Systems
    • COMMUNICATION (2 Of 2) -- (A3 SEDAN)
    • Interior Lights, Lamps And Switches -- (A3 Sedan)
  • Exterior Lights
    • Exterior Lights, Lamps And Switches (Safety Precaution) -- (A3 Sedan)
    • Exterior Lights, Switches -- (A3 Sedan)
  • Gauges & Instrument Panels
    • Instruments -- (A3 Sedan)
  • Infotainment
    • COMMUNICATION (1 Of 2) -- (A3 SEDAN)
    • COMMUNICATION (2 Of 2) -- (A3 SEDAN)
    • Interior Lights, Lamps And Switches -- (A3 Sedan)
  • Interior/Exterior Trim
    • Exterior Equipment -- (A3 Sedan)
    • General, Technical Data - Body Interior -- (Sedan)
    • Interior Equipment
    • Interior Equipment -- (Sedan)
    • Interior Trim -- (A3 Sedan)
  • Interior/Illumination Lights
    • General, Technical Data - Body Interior -- (Sedan)
    • Interior Lights, Lamps And Switches -- (A3 Sedan)
    • Interior Lights, Switches -- (A3 Sedan)
  • Mirrors
    • Exterior Equipment -- (A3 Sedan)
  • Seats
    • Interior Equipment
    • Interior Equipment -- (Sedan)
    • Seat Frames -- (A3 Sedan)
    • Seat Upholstery, Covers -- (A3 Sedan)
  • Warning Systems
    • COMMUNICATION (2 Of 2) -- (A3 SEDAN)
  • Window Motors & Regulators
    • Exterior Equipment -- (A3 Sedan)
    • Front Doors, Central Locking System -- (A3 Sedan)
    • Glass, Window Regulators -- (A3 Sedan)
    • Rear Doors -- (A3 Sedan)
  • Wiper/Washer Systems
    • Windshield Washer System -- (A3 Sedan)
    • Wiper/Washer Systems -- (A3 Sedan)
  • Wiring System (Data Link Connectors, Pwr Dist., Grnd Dist.)
    • Wires -- (A3 Sedan)
    • Wiring -- (A3 Sedan)
• Body & Frame
  • Body, Cab Control Systems
    • General, Technical Data - (Exterior) -- (A3 Sedan)
    • General, Technical Data - Body Interior -- (Sedan)
  • Door Locks
    • Front Doors, Central Locking System -- (A3 Sedan)
    • Interior Lights, Lamps And Switches -- (A3 Sedan)
    • Interior Lights, Switches -- (A3 Sedan)
  • Exterior Body Panels
    • Body Front -- (A3 Sedan)
    • Bumpers -- (A3 Sedan)
    • Exterior Equipment -- (A3 Sedan)
    • Front Doors, Central Locking System -- (A3 Sedan)
    • General, Technical Data - (Exterior) -- (A3 Sedan)
    • Hood, Lids -- (A3 Sedan)
    • Rear Doors -- (A3 Sedan)
  • Exterior/Interior Trim
    • Exterior Equipment -- (A3 Sedan)
    • General, Technical Data - Body Interior -- (Sedan)
    • Interior Equipment
    • Interior Equipment -- (Sedan)
    • Interior Trim -- (A3 Sedan)
  • Mirrors
    • Exterior Equipment -- (A3 Sedan)
  • Seats
    • Interior Equipment
    • Interior Equipment -- (Sedan)
    • Seat Frames -- (A3 Sedan)
    • Seat Upholstery, Covers -- (A3 Sedan)
  • Sun Roof/T-Top/Convertible Top
    • Sunroof -- (A3 Sedan)
  • Windows
    • Exterior Equipment -- (A3 Sedan)
    • Front Doors, Central Locking System -- (A3 Sedan)
    • Glass, Window Regulators -- (A3 Sedan)
    • Rear Doors -- (A3 Sedan)
• Brakes
  • Anti-Lock Brakes
    • Antilock Brake System -- (Sedan)
    • General, Technical Data Brakes -- (Sedan)
  • Brakes Control Systems
    • General, Technical Data Brakes -- (Sedan)
  • Mechanical - Hydraulic
    • Hydraulic Components (Brake System)
    • Hydraulic Components (Brakes) -- (Sedan)
    • Mechanical Components (Brakes) -- (Sedan)
  • Parking Brake System
    • Mechanical Components (Brakes) -- (Sedan)
  • Traction Control
    • Antilock Brake System -- (Sedan)
    • General, Technical Data Brakes -- (Sedan)
• Drivelines & Axles
  • Axle Shafts
    • Front Suspension -- (A3 Sedan)
  • Differentials & Drive Axles
    • FINAL DRIVE, DIFFERENTIAL [0D9] (1 Of 2) -- (SEDAN)
    • FINAL DRIVE, DIFFERENTIAL [0D9] (2 Of 2) -- (SEDAN)
    • Final Drive, Differential 7-Speed Dual Clutch Transmission 0DL
    • Final Drive, Differential Rear Final Drive
  • Driveshaft & Universal Joints
    • Final Drive, Differential Rear Final Drive
• Electrical
  • Body Electrical
    • General, Technical Data - Electrical Equipment -- (A3 Sedan)
    • OEM Connector End Views
    • Wires -- (A3 Sedan)
    • Wiring -- (A3 Sedan)
  • Charging Systems
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Battery & Charging)
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Start/Stop System)
    • General, Technical Data - Electrical Equipment -- (A3 Sedan)
  • RS 3 - Component Locations
  • Fuses & Circuit Breakers
    • Wires -- (A3 Sedan)
    • Wiring -- (A3 Sedan)
  • Gauges
    • Instruments -- (A3 Sedan)
  • Motors, Switches, Relays
    • General, Technical Data - Electrical Equipment -- (A3 Sedan)
    • OEM Connector End Views
    • Wires -- (A3 Sedan)
    • Wiring -- (A3 Sedan)
  • Starter
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Battery & Charging)
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Start/Stop System)
  • Wiring Diagrams
    • OEM Connector End Views
    • Using lemon2025'S System Wiring Diagrams
• Engine Mechanical
  • Blowers, Superchargers & Turbochargers
    • FUEL SUPPLY (1 Of 2) -- (A3 SEDAN)
    • Fuel Supply System -- (A3 Sedan)
    • Turbocharger, Supercharger 2.5L
    • Turbocharger, Supercharger Servicing 2.5L
  • Cooling Fan
    • COOLING SYSTEM (4-Cylinder Direct Injection 1.8L; 2.0L 4V TFSI Engine) -- (A3 SEDAN)
    • Cooling System Servicing 2.5L
  • Cooling System (Mechanical)
    • COOLING SYSTEM (4-Cylinder Direct Injection 1.8L; 2.0L 4V TFSI Engine) -- (A3 SEDAN)
    • Cooling System Servicing 2.5L
    • GENERAL, TECHNICAL DATA - [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • General, Technical Data - Engine -- (A3 Sedan)
  • Exhaust
    • EXHAUST SYSTEM, EMISSION CONTROLS (4-Cylinder 2.0L 4V TFSI Engine) -- (A3 SEDAN)
    • Exhaust System, Emission Controls 2.5L
    • Exhaust System, Emission Controls Servicing 2.5L
    • General Information (Maintenance Procedures) -- (A3)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Fuel System
    • General Information (Maintenance Procedures) -- (A3)
    • GENERAL, TECHNICAL DATA - [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • General, Technical Data - Engine -- (A3 Sedan)
    • General, Technical Data - Fuel Supply -- (A3 Sedan)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • MULTIPORT Fuel Injection 2.5L
    • MULTIPORT Fuel Injection Servicing 2.5L
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Lubrication System
    • General Information (Maintenance Procedures) -- (A3)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • LUBRICATION [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • Lubrication 2.5L
    • Lubrication Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Mechanical
    • Crankshaft 2.5L
    • Crankshaft, Cylinder Block Servicing 2.5L
    • CYLINDER HEAD, VALVETRAIN (4-Cylinder 2.0L 4V TFSI Engine) -- (A3 SEDAN)
    • Cylinder Head, VALVETRAIN 2.5L
    • Cylinder Head, VALVETRAIN Servicing 2.5L
    • ENGINE ASSEMBLY (4-Cylinder 2.0L 4V TFSI Engine) -- (A3 SEDAN)
    • Engine Assembly 2.5L
    • Engine Assembly Servicing 2.5L
    • General Information (Maintenance Procedures) -- (A3)
    • GENERAL, TECHNICAL DATA - [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • General, Technical Data - Engine -- (A3 Sedan)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Starter
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Battery & Charging)
    • Charging System (Battery, Starter, Generator) & Cruise Control -- (A3 Sedan) (Start/Stop System)
• Engine Performance
  • Emissions
    • Emission Applications
    • Emission Control Abbreviations
    • State Emission Standards - Diesel
    • State Emission Standards - Gas
  • Fuel Delivery
    • General Information (Maintenance Procedures) -- (A3)
    • GENERAL, TECHNICAL DATA - [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • General, Technical Data - Engine -- (A3 Sedan)
    • General, Technical Data - Fuel Supply -- (A3 Sedan)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • MULTIPORT Fuel Injection 2.5L
    • MULTIPORT Fuel Injection Servicing 2.5L
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Ignition System
    • General Information (Maintenance Procedures) -- (A3)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Ignition/Glow Plug System 2.5L
    • Ignition/Glow Plug System Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Remove, Overhaul & Install
    • General Information (Maintenance Procedures) -- (A3)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
  • Specifications
    • Firing Order & Cylinder Identification
  • Tune-Up
    • General Information (Maintenance Procedures) -- (A3)
    • General, Technical Data 2.5L
    • General, Technical Data Servicing 2.5L
    • Ignition/Glow Plug System 2.5L
    • Ignition/Glow Plug System Servicing 2.5L
    • Maintenance Procedures (General Information) -- (A3)
    • Wiring Diagram (CHHB, CJXB, CJXC, CJXF, CNTC, CYFB, CJXG, CJXD) -- (A3 Sedan)
• General Information
  • Abbreviations
    • Commonly Used Abbreviations - General Information
    • Emission Control Abbreviations
  • Basic Trouble Shooting
    • Basic Trouble Shooting - General Information
    • Commonly Used Abbreviations - General Information
    • Emission Control Abbreviations
    • Engine Performance - Trouble Shooting - General Information
  • Brakes
    • Anti-Lock Brake Safety Precautions - General Information
    • Map - Brake Systems
    • Map - Routine Inspection Reference Guide
  • Check Lists
    • Symptom Check List Worksheet - General Information
  • Driveline/Axles
    • Drive Axle Noise Diagnosis - General Information
    • Gear Tooth Contact Patterns - General Information
    • Map - Drive Train & Transmission
    • Trouble Shooting - Clutches - General Information
  • DTC Index (A3 Sedan)
  • Electrical
    • Map - Electrical Systems
    • Using lemon2025'S System Wiring Diagrams
  • Engine
    • Engine Overhaul Procedures - General Information
    • General Cooling System Service - General Information
  • Engine Performance
    • Electrostatic Discharge Warning - General Information
    • Engine Performance Diagnostic Routine Outline - General Information
    • Engine Performance Safety Precautions
    • Map - Engine Performance & Maintenance
    • Parasitic Load Explanation & Test Procedures - General Information
    • State Emission Standards - Diesel
    • State Emission Standards - Gas
    • Waveforms - Injector Pattern Tutorial - General Information
  • Map - Exhaust Systems
  • Heating, Ventilation & A/C (HVAC)
    • Map - Heating, Ventilation, & Air Conditioning
  • Identification
    • CANADIAN Model Cross-Reference
    • GENERAL, TECHNICAL DATA - [4-Cylinder 2.0L 4V TFSI Engine] -- (A3 SEDAN)
    • General, Technical Data - Engine -- (A3 Sedan)
  • Metric Conversions
    • Engine Displacement Conversion Table - ECAT
    • Metric Conversions
  • OEM General Information
    • Automatic Stop/Start Disable
    • Wires -- (A3 Sedan)
  • Maintenance Reminder Light (Reset Procedures)
  • Specifications Index
    • Common Specifications & Procedures (Sedan)
  • Steering
    • Map - Steering, Suspension, Wheel Alignment, Wheels & Tires
    • Wheel Alignment Theory & Operation - General Information
  • Traction Control Disable Procedures
  • Trouble Shooting - Manual Transmission - General Information
• Heating, Ventilation & A/C (HVAC)
  • A/C Compressor
    • Air Conditioning (Front Heater & A/C Unit) -- (Sedan)
    • Air Conditioning (Overview) -- (Sedan)
  • General Servicing
    • Air Conditioning (Front Heater & A/C Unit) -- (Sedan)
    • Air Conditioning (Overview) -- (Sedan)
    • General, Technical Data (HVAC) -- (A3 Sedan)
    • GENERAL, TECHNICAL DATA (R1234yf) -- (A3 SEDAN)
  • HVAC Control Systems
    • Air Conditioning (Front Heater & A/C Unit) -- (Sedan)
    • Air Conditioning (Overview) -- (Sedan)
    • AIR CONDITIONING R1234yf (A/C SERVICE STATION) -- (SEDAN)
    • AIR CONDITIONING R1234yf (REFRIGERANT CIRCUIT) -- (SEDAN)
    • AIR CONDITIONING R1234yf (TOOLS & TESTING EQUIPMENT) -- (SEDAN)
    • AIR CONDITIONING R134a (GENERAL INFORMATION) -- (SEDAN)
    • AIR CONDITIONING R134a (REFRIGERANT CAPACITIES) -- (SEDAN)
    • AIR CONDITIONING R134a (REFRIGERANT CIRCUIT COMPONENTS) -- (SEDAN)
    • AIR CONDITIONING R134a (REFRIGERANT CIRCUIT) -- (SEDAN)
    • AIR CONDITIONING R134a (WARNINGS) -- (SEDAN)
    • General, Technical Data (HVAC) -- (A3 Sedan)
    • GENERAL, TECHNICAL DATA (R1234yf) -- (A3 SEDAN)
    • Heating, Ventilation
    • Heating, Ventilation -- (Sedan)
• Maintenance
  • Procedures
    • Maintenance Reminder Light (Reset Procedures)
    • Maintenance Schedule, Diagnosis (2017)
    • MAINTENANCE, DIAGNOSIS (FLUID CAPACITY TABLES) (1 Of 3) -- (A3 SEDAN)
    • MAINTENANCE, DIAGNOSIS (FLUID CAPACITY TABLES) (2 Of 3) -- (A3 SEDAN)
    • Maintenance, Diagnosis (Fluid Capacity Tables) (3 Of 3) -- (A3 Sedan)
    • Maintenance, Diagnosis (Intervals) -- (A3 Sedan)
    • Maintenance, Diagnosis (Schedule) -- (A3 Sedan)
• Restraints
  • Air Bag, SRS
    • General, Technical Data - Body Interior -- (Sedan)
    • Passenger Protection, Airbags, Seat Belts -- (Sedan)
  • Passive Restraints
    • General, Technical Data - Body Interior -- (Sedan)
    • Interior Equipment
    • Interior Equipment -- (Sedan)
    • Passenger Protection, Airbags, Seat Belts -- (Sedan)
  • Restraints Control Systems
    • General, Technical Data - Body Interior -- (Sedan)
  • Seat Belts
    • General, Technical Data - Body Interior -- (Sedan)
• Steering
  • Manual Steering
    • Steering (Sedan)
  • Power Steering
    • Steering (Sedan)
  • Steering Column
    • Steering (Sedan)
  • Steering Gear
    • General, Technical Data, Suspension -- (Sedan)
    • Steering (Sedan)
  • Steering Linkage
    • Steering (Sedan)
• Suspension
  • Electronic Suspension
    • Self-Leveling Suspension -- (A3 Sedan)
  • Front Suspension
    • Front Suspension -- (A3 Sedan)
    • General, Technical Data, Suspension -- (Sedan)
  • Rear Suspension
    • General, Technical Data, Suspension -- (Sedan)
    • Rear Suspension -- (A3 Sedan)
  • Wheel Alignment
    • General, Technical Data, Suspension -- (Sedan)
    • Wheels, Tires, Wheel Alignment (Suspension, Wheels, Steering) -- (A3 Sedan)
  • Wheels & Tire System
    • Wheels, Tires, Wheel Alignment (Suspension, Wheels, Steering) -- (A3 Sedan)
    • Wheels, Tires, Wheel Alignment (Wheel And Tire General Information) -- (A3 Sedan)
    • Wheels, Tires, Wheel Alignment (Wheel And Tire Guide) -- (A3 Sedan)
    • Wheels, Tires, Wheel Alignment (Wheel And Tire Guide) (Air Pressures) -- (A3 Sedan)
• Transmission
  • Automatic Trans
    • Gears, Shafts (A3 Sedan)
  • Clutch 7-Speed Dual Clutch Transmission 0DL
  • Manual Trans
    • Final Drive, Differential Rear Final Drive
    • Gears, Shafts (A3 Sedan)
  • Transmission Control Systems
    • Controls, Housing 7-Speed Dual Clutch Transmission 0DL
    • FINAL DRIVE, DIFFERENTIAL [0D9] (1 Of 2) -- (SEDAN)
    • FINAL DRIVE, DIFFERENTIAL [0D9] (2 Of 2) -- (SEDAN)
    • Final Drive, Differential 7-Speed Dual Clutch Transmission 0DL
• External Pages