2021 Audi A3 Sportback Service and Repair Manual

This 2021 Audi A3 Sportback Service and Repair Manual Covers

Engine & Drivetrain

• 1.0L TFSI petrol engine service and repair (market dependent)
• 1.5L TFSI petrol engine service and repair
• 1.5L TFSI Mild Hybrid (MHEV) system diagnostics (where equipped)
• 2.0L TFSI petrol engine servicing
• 2.0L TDI diesel engine repair procedures (where available)
• TFSI e plug-in hybrid system diagnostics and repair (where equipped)
• Fuel injection and turbocharger diagnostics
• Engine cooling system servicing
• Exhaust and emissions control system diagnostics
• 6-speed manual transmission servicing (where equipped)
• 7-speed S tronic transmission diagnostics and repair
• quattro all-wheel drive system servicing (where equipped)
• Driveshaft, differential, and CV joint repairs

Braking Systems

• Hydraulic brake system servicing
• Anti-lock Braking System (ABS) diagnostics
• Electronic Stability Control (ESC) diagnostics
• Electronic Parking Brake (EPB) servicing
• Auto Hold system diagnostics
• Brake Assist system diagnostics
• Brake pad, disc, and caliper replacement procedures

Chassis & Suspension

• Front MacPherson strut suspension repairs
• Rear multi-link suspension servicing
• Adaptive suspension diagnostics (where equipped)
• Progressive steering diagnostics
• Wheel alignment specifications
• Wheel bearing replacement procedures
• Suspension component inspection and troubleshooting

Electrical & Wiring

• Complete factory wiring diagrams
• Battery management system diagnostics
• 12V electrical system servicing
• CAN Bus, LIN Bus, and FlexRay communication diagnostics
• Gateway control module diagnostics
• Body Control Module (BCM) diagnostics
• Audi Virtual Cockpit diagnostics
• Audi MMI Navigation Plus diagnostics
• Infotainment system troubleshooting
• Wireless Apple CarPlay® and Android Auto™ diagnostics (where equipped)
• USB-C ports and wireless charging system diagnostics (where equipped)

Air Conditioning & HVAC

• Automatic climate control diagnostics
• Air conditioning compressor servicing
• Refrigerant recovery and recharge procedures
• Air quality sensor diagnostics
• HVAC control module testing
• Heating and ventilation system repairs

Body & Interior

• Interior trim removal and installation
• Dashboard servicing procedures
• Door control module diagnostics
• Power window and central locking repairs
• Matrix LED headlamp diagnostics (where equipped)
• Interior ambient lighting diagnostics (where equipped)
• Airbag and occupant restraint system diagnostics
• Electrically adjustable seat servicing (where equipped)

Advanced Driver Assistance Systems (ADAS)

• Audi Pre Sense Front diagnostics
• Adaptive Cruise Assist diagnostics (where equipped)
• Lane Departure Warning system servicing
• Lane Change Assist diagnostics (where equipped)
• Blind Spot Monitoring diagnostics (where equipped)
• Rear Cross Traffic Assist servicing (where equipped)
• Front camera calibration procedures
• Radar sensor calibration
• Parking Assist diagnostics
• Ultrasonic parking sensor diagnostics
• Traffic Sign Recognition diagnostics (where equipped)
• 360-degree camera calibration (where equipped)

Diagnostics & Troubleshooting

• ODIS factory diagnostic procedures
• Diagnostic Trouble Code (DTC) lookup procedures
• Guided fault-finding routines
• ECU coding and adaptation procedures
• Software update procedures
• Sensor and actuator testing
• Component protection diagnostics
• Step-by-step troubleshooting workflows

Common Error Codes Covered

This manual includes diagnostic procedures for common Audi fault codes applicable to the 2021 Audi A3 Sportback.

Engine Codes

• P0299 – Turbocharger Underboost Condition
• P0300 – Random/Multiple Cylinder Misfire Detected
• P0171 – System Too Lean (Bank 1)
• P20EE – SCR NOx Catalyst Efficiency Below Threshold (diesel models)
• P0A80 – Hybrid Battery Pack Performance (TFSI e models)

Transmission Codes

• P0726 – Engine Speed Input Circuit Range/Performance
• P1735 – S tronic Clutch Adaptation Fault
• P17BF – Hydraulic Pump Protection Fault

ABS & Chassis Codes

• C0031 – Left Front Wheel Speed Sensor Fault
• C10AC – Electronic Parking Brake Malfunction
• C1146 – Steering Angle Sensor Calibration Fault

Network Communication Codes

• U0100 – Lost Communication with ECM/PCM
• U1113 – Function Restriction Due to Missing Message
• U1123 – Data Bus Communication Fault

Body Control & ADAS Codes

• B2000 – Control Module Internal Malfunction
• B126A – Front Camera Calibration Required
• C1103 – Radar Sensor Misalignment
• C1116 – Lane Assist Camera Fault

The manual also includes hundreds of manufacturer-specific fault codes, wiring diagrams, guided diagnostic routines, calibration procedures, software configuration information, and repair instructions.

Who Is This Manual For?

• Professional automotive workshops
• Audi dealership technicians
• Independent repair garages
• Mobile mechanics
• Automotive engineering students
• DIY enthusiasts with professional diagnostic equipment

If you are servicing, maintaining, diagnosing, or repairing a 2021 Audi A3 Sportback, this factory workshop manual provides the detailed repair procedures, wiring diagrams, calibration instructions, and diagnostic information needed to complete repairs accurately and to Audi factory standards.