The fifth-generation (Mk5) Audi A4 and S4 (chassis codes B9/8W) , Audi’s premium luxury sedan and its high-performance variant, has been produced from 2015 to 2024 . Known for its innovative technology, refined design, and impressive performance, this generation of the A4 and S4 has solidified its reputation as a leader in the luxury sedan market.
In this article, you will find detailed fuse box diagrams for Audi A4 and S4 models produced in 2015, 2016, 2017, 2018 and 2019 . These diagrams provide valuable insights into the vehicle’s electrical systems, helping owners and technicians understand the assignment of each fuse (fuse layout). This information is crucial for diagnosing electrical issues, performing maintenance, or addressing necessary repairs.
This guide is an indispensable resource for understanding the electrical system of the fifth-generation Audi A4 and S4, ensuring that owners have the tools and knowledge to maintain the functionality, reliability, and performance of these luxurious sedans.
The cigar lighter / power outlet fuse in the Audi A4/S4 is fuse No.6 located in the Black Fuse Panel C within the Driver’s/Front Passenger’s Footwell Fuse Box .
Driver’s/front passenger’s footwell
Left-hand drive vehicles: It is located under the footrest.Right-hand drive vehicles: Behind the cover under the glove box.
It is located in the left side of the trunk behind the trim panel.
Driver’s/front passenger’s footwell (LHD)
Front passenger‘s footwell (RHD)
Assignment of the fuses in the Passenger compartment (footwell) (2015, 2016, 2017)
Number Electric equipment Brown panel A 1 — 2 Mass airflow sensor, camshaft adjustment 3 Exhaust doors, fuel injectors, radiator inlet 4 Vacuum pump, hot water pump, particulate sensor, biodiesel sensor 5 Brake light sensor 6 Engine valves 7 Heated oxygen sensor, mass airflow sensor 8 Water pump, high pressure pump, high pressure regulator valve 9 Hot water pump 10 Oil pressure sensor, oil temperature sensor 11 Clutch pedal position sensor 12 Engine valves 13 Radiator fan 14 Fuel injectors 15 Ignition coils 16 Fuel pump Red panel B 1 Anti-theft alarm system 2 Engine control module 3 Lumbar support 4 Automatic transmission selector mechanism 5 Horn 6 Electromechan ical park ing brake 7 Gateway control module 8 Interior headl iner lights 9 — 10 Airbag control module 11 Electronic Stabilization Control (ESC 12 Diagnostic connector, light/rain sensor 13 Climate control system 14 Right front door control module 15 A/C compressor Black panel C 1 Front seat heating 2 Windshield wipers 3 Left head light electronics 4 Panorama glass roof/ sliding/tilting sunroof 5 Left front door control module 6 Sockets 7 Right rear door control module 8 — 9 Right headlight electronics 10 Windshield washer system/headlight washer system 11 Left rear door control module Black panel D 1 Seat ventilation, rearv iew mirror, rear climate control system controls 2 Gateway, climate control system 3 Sound actuator/exhaust sound tuning 4 Clutch pedal position sensor 5 Engine start 6 — 7 — 8 Homelink 9 Adaptive cruise control 10 — 11 Video camera 12 Matrix LED headlight/right LED headlight 13 Matrix LED headlight/left LED headlight 14 Rear window wiper Red panel E 1 Ignition coils 2 Natural gas tank valves 3 — 4 — 5 Engine mount 6 Automat ic transmission 7 Instrument panel 8 Climate control system (blower) 9 — 10 Dynamic steering 11 Engine start
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Assignment of the fuses in the Driver’s side cockpit (2015, 2016, 2017)
Number Electric equipment 1 — 2 Telephone 3 — 4 Head-up display 5 Audi music interface 6 Front climate control system controls 7 Steering column lock 8 Infotainment syst em display 9 Instrument cluster 10 Infotainment unit 11 Light switch 12 Steering column electronics 13 — 14 Infotainment system 15 — 16 Steering wheel heating
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Assignment of the fuses in the Left luggage compartment (2015, 2016, 2017)
Number Electric equipment Black panel A 1 — 2 Windshield defroster 3 Windshield defroster 4 — 5 Suspension control 6 Automatic transmission 7 Rear window defogger 8 Rear seat heating 9 Tail lights 10 Left safety belt tensioner 11 Central locking 12 Electric luggage compartment lid Red panel B – Not assigned Brown panel C 1 — 2 Telephone 3 Lumbar support 4 Audi side assist 5 — 6 — 7 — 8 — 9 — 10 — 11 — 12 Homelink 13 Rearview camera, peripheral cameras 14 Right tail lights 15 — 16 Right safety belt tensioner Red panel E 1 — 2 Sound-amplifier 3 AdBlue 4 — 5 Trailer hitch (right light) 6 — 7 Trailer hitch 8 Trailer hitch (left light) 9 Trailer hitch (socket) 10 Sport differential 11 Ad Blue
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Driver’s/front passenger’s footwell (LHD)
Front passenger‘s footwell (RHD)
Assignment of the fuses in the Passenger compartment (footwell) (2018)
Number Electric equipment Brown panel A 1 — 2 Mass airflow sensor, camshaft adjustment, charge air cooler pump 3 Exhaust doors, fuel injectors, radiator inlet 4 Vacuum pump, hot water pump, particulate sensor, biodiesel sensor 5 Brake light sensor 6 Engine valves, camshaft adjustment 7 Heated oxygen sensor, mass airflow sensor 8 Water pump, high pressure pump, high pressure regulator valve 9 Hot water pump 10 Oil pressure sensor, oil temperature sensor 11 Clutch pedal position sensor 12 Engine valves 13 Radiator fan 14 Fuel injectors 15 Ignition coils 16 Fuel pump Red panel B 1 Anti-theft alarm system 2 Engine control module 3 Lumbar support 4 Automatic transmission selector mechanism 5 Horn 6 Electromechanical park ing brake 7 Gateway control module 8 Interior headl iner lights 9 — 10 Airbag control module 11 Electronic Stabilization Control (ESC) 12 Diagnostic connector, light/rain sensor 13 Climate control system 14 Right front door control module 15 A/C compressor Black panel C 1 Front seat heating 2 Windshield wipers 3 Left head light electronics 4 Panorama glass roof/ sliding/tilting sunroof 5 Left front door control module 6 Sockets 7 Right rear door control module 8 All wheel drive 9 Right headlight electronics 10 Windshield washer system/headlight washer system 11 Left rear door control module Black panel D 1 Seat ventilation, rearv iew mirror, rear climate control system controls 2 Gateway, climate control system 3 Sound actuator/exhaust sound tuning 4 Clutch pedal position sensor 5 Engine start 6 — 7 Rear USB charg ing port 8 Homelink 9 Adaptive cruise control 10 — 11 Video camera 12 Matrix LED headlight/right LED headlight 13 Matrix LED headlight/left LED headlight 14 Rear window wiper Red panel E 1 Ignition coils 2 Natural gas tank valves 3 — 4 — 5 Engine mount 6 Automatic transmission 7 Instrument panel 8 Climate control system (blower) 9 — 10 Dynamic steering 11 Engine start
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Assignment of the fuses in the Driver’s side cockpit (2018)
Number Electric equipment 1 — 2 Telephone 3 — 4 Head-up display 5 Audi music interface, USB charging port 6 Front climate control system controls 7 Steering column lock 8 Infotainment system display 9 Instrument cluster 10 Infotainment unit 11 Light switch 12 Steering column electronics 13 — 14 Infotainment system 15 — 16 Steering wheel heating
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Assignment of the fuses in the Left luggage compartment (2018)
Number Electric equipment Black panel A 1 — 2 Windshield defroster 3 Windshield defroster 4 — 5 Suspension control 6 Automatic transmission 7 Rear window defogger 8 Rear seat heating 9 Tail lights 10 Left safety belt tensioner 11 Central locking system 12 Electric luggage compartment lid Red panel B — Not assigned Brown panel C 1 — 2 Telephone 3 Lumbar support 4 Audi side assist 5 — 6 — 7 — 8 Smart module (tank) 9 — 10 — 11 12 Volt battery 12 Homelink 13 Rearview camera, peripheral cameras 14 Right tail lights 15 — 16 Right safety belt tensioner Red panel E 1 — 2 Sound-amplifier 3 AdBlue heating 4 — 5 Trailer hitch (right light) 6 — 7 Trailer hitch 8 Trailer hitch (left light) 9 Trailer hitch (socket) 10 Sport differential 11 Ad Blue
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Driver’s/front passenger’s footwell (LHD)
Front passenger‘s footwell (RHD)
Assignment of the fuses in the Passenger compartment (footwell) (2019)
№ Equipment Fuse panel A (brown) 2 Mass airflow sensor, camshaft adjustment, charge air cooler pump 3 Exhaust doors, fuel injectors, radiator inlet, crankshaft housing heater 4 Vacuum pump, hot water pump, particulate sensor, biodiesel sensor, exhaust doors 5 Brake light sensor 6 Engine valves, camshaft adjustment 7 Heated oxygen sensor, mass airflow sensor 8 Water pump, high pressure pump, high pressure regulator valve 9 Hot water pump 10 Oil pressure sensor, oil temperature sensor 11 Clutch pedal position sensor, engine start 12 Engine valves 13 Radiator fan 14 Fuel injectors, engine control module 15 Ignition coils, heated oxygen sensors 16 Fuel pump Fuse panel B (red) 1 Anti-theft alarm system 2 Engine control module 3 Lumbar support 4 Automatic transmission selector mechanism 5 Horn 6 Electromechanical parking brake 7 Gateway control module 8 Interior headliner lights 9 Emergency call system 10 Airbag control module 11 Electronic Stabilization Control (ESC) 12 Diagnostic connector, light/rain sensor 13 Climate control system 14 Right front door control module 15 A/C compressor Fuse 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 Sockets 7 Right rear door control module 8 All wheel drive 9 Right headlight electronics 10 Windshield washer system/headlight washer system 11 Left rear door control module Fuse panel D (black) 1 Seat ventilation, rearview mirror, climate control system, rear climate control system controls, windshield defogger 2 Gateway, climate control system 3 Sound actuator/exhaust sound tuning 4 Clutch pedal position sensor 5 Engine start 7 Rear USB charging port 8 Garage door opener 9 Adaptive cruise control 10 Exterior sound 11 Video camera 12 Matrix LED headlight/right LED headlight 13 Matrix LED headlight/left LED headlight 14 Rear window wiper 16 Rear Seat Entertainment preparation Fuse panel E (red) 1 Ignition coils 5 Engine mount 6 Automatic transmission 7 Instrument panel 8 Climate control system (blower) 10 Dynamic steering 11 Engine start
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Assignment of the fuses in the Driver’s side cockpit (2019)
№ Equipment 1 Vehicle opening/start (NFC) 2 Telephone 4 Head-up display 5 Audi music interface, USB charging port 6 Front climate control system controls 7 Steering column lock 8 Infotainment system display 9 Instrument cluster 10 Infotainment unit 11 Light switch, switch panel 12 Steering column electronics 14 Infotainment system 16 Steering wheel heating
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Assignment of the fuses in the Left luggage compartment (2019)
№ Equipment Fuse 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 Left safety belt tensioner 11 Central locking system 12 Luggage compartment lid Fuse panel B (red) Not assigned Fuse panel C (brown) 2 Telephone 3 Lumbar support Fuse panel D (brown) 4 Audi side assist 5 Rear Seat Entertainment preparation 7 Vehicle opening/start (NFC) 8 Smart module (tank) 11 Auxiliary battery control module 12 Garage door opener 13 Rearview camera, peripheral cameras 14 Right tail lights 16 Right safety belt tensioner Fuse panel E (red) 2 Sound-amplifier 3 AdBlue heating 5 Trailer hitch (right light) 7 Trailer hitch 8 Trailer hitch (left light) 9 Trailer hitch (socket) 10 Sport differential 11 AdBlue heating
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