The facelifted fifth-generation (Mk5) Audi A4 and S4 (chassis codes B9/8W) , Audi’s luxury sedan and its high-performance variant, has been produced in 2020, 2021, 2022, 2023 and 2024 . Renowned for its sleek design updates, cutting-edge technology, and refined performance, the facelifted A4 and S4 continue to dominate the premium sedan segment.
In this article, you will find detailed fuse box diagrams for Audi A4 and S4 models produced from 2020 to 2024 . These diagrams provide critical insights into the vehicle’s electrical systems, helping owners and technicians understand the assignment of each fuse (fuse layout). This information is essential for diagnosing electrical issues, performing routine maintenance, or completing necessary repairs.
This guide serves as a comprehensive resource for understanding the electrical system of the facelifted fifth-generation Audi A4 and S4, ensuring that owners have the tools and knowledge needed to maintain the reliability, functionality, and performance of these sophisticated luxury sedans.
Driver’s/front passenger’s footwell
The fuses are located in the footwell under the foot rest (left-hand drive vehicle) or behind the cover (right-hand drive vehicle).
Additional fuses are located on the front side of the cockpit (driver’s side).
The fuses are located under the left cover in the luggage compartment.
Driver’s/front passenger’s footwell
LHD
RHD
Assignment of the fuses in the front passenger footwell
№ Equipment Panel A (brown) 1 Catalytic converter heating 2 Engine components 3 Exhaust doors, fuel injectors, air intake, motor heating 4 Vacuum pump, hot water pump, NOx sensor, particulate sensor, biodiesel sensor, exhaust doors 5 Brake light sensor 6 Engine valves, camshaft adjustment 7 Heated oxygen sensors, mass airflow sensor, water pump 8 Water pump, high pressure pump, high pressure regulator valve, temperature valve, engine mount 9 2020: Hot water pump, engine relay 10 Oil pressure sensor, oil temperature sensor 11 Clutch position sensor, 48 V starter generator, water pump, 12V starter generator 12 Engine valves, engine mount 13 Engine cooling 14 Fuel injectors, drive system control module 15 Ignition coils, heated oxygen sensors 16 Fuel pump Panel B (red) 1 Anti-theft alarm system 2 Drive system control module 3 Left front seat electronics, lumbar support, massaging seat 4 Automatic transmission selector lever 5 Horn 6 Parking brake 7 Diagnostic interface (Gateway control module) 8 Roof electronics control module 9 Emergency call and communication control module 10 Airbag control module 11 Electronic Stabilization Control (ESC), Anti-Lock Braking System (ABS) 12 Diagnostic connection, light/rain sensor 13 Climate control system 14 Right front door control module 15 Climate control system compressor 16 from 2021: Brake system pressure reservoir Panel C (black) 1 Front seat heating 2 Windshield wipers 3 Left headlight electronics 4 Panoramic glass roof / sliding/tilting sunroof 5 Left front door control module 6 12 volt socket 7 Right rear door control module, right rear power window 8 All wheel drive (AWD) control module 9 Right headlight electronics 10 Windshield washer system/headlight washer system control module n Left rear door control module, left rear power window 12 Parking heater Panel D (black) 1 Front seat electronic, seat ventilation, rearview mirror, rear climate control system control panel, windshield heating, diagnostic connection 2 Diagnostic interface, vehicle electrical system control module 3 Sound generator 4 Clutch position sensor 5 Engine start, emergency shut-off 6 Diagnostic connection, traffic information antenna (TMC) 7 USB connection 8 Garage door opener 9 Audi adaptive cruise control, adaptive distance regulation 11 Front camera 12 Right headlight 13 Left headlight 14 Transmission fluid cooling 15 2020: Alarm and hands-free calling system Panel E (red) 1 Ignition coils 2 Climate control system compressor 5 Left headlight 6 Automatic transmission 7 Instrument panel 8 Climate control system blower 9 Right headlight 10 Dynamic steering 11 Engine start
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Assignment of the fuses in the driver’s side of the cockpit
№ Equipment 1 Convenience access and start authorization control module (NFC) 2 Audi phone box, USB connection 4 Head-up display 5 Audi music interface, USB connection 6 Front climate control system control panel 7 Steering column lock 8 Center display 9 Instrument cluster 10 Volume control 11 Light switch, switch module 12 Steering column electronics 13 2020: Particulate matter sensor for climate control system 14 Infotainment system 16 2020: Steering wheel heating
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Assignment of the fuses in the trunk
№ Equipment Panel A (black) 2 Windshield defroster 3 Windshield defroster 5 Suspension control 6 Automatic transmission 7 Rear window defogger 8 Rear seat heating 9 Left tail lights 10 Airbag, driver’s side safety belt tensioner control module 11 Luggage compartment lid lock, fuel filler door lock, convenience system control module 12 Luggage compartment lid Panel B (red) 6 2020: Battery power interrupt Panel C (brown) 1 from 2021: Exterior antenna 2 Audi phone box 3 Right front seat electronics, lumbar support, massaging seat 4 Side assist 6 Tire pressure monitoring system 7 Convenience access and start authorization control module (NFC) 8 Auxiliary heating, tank module 10 TV tuner, data exchange and telematics control module 11 Auxiliary battery control module 12 Garage door opener 13 Rearview camera, peripheral cameras 14 Right tail lights 16 Airbag, front passenger’s side safety belt tensioner control module Panel E (red) 3 Exhaust treatment 5 Right trailer hitch light 7 Trailer hitch 8 Left trailer hitch light 9 Trailer hitch socket 10 All wheel drive control module, sport differential 11 Exhaust treatment
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