Audi A4 and S4 B9/8W – fuse box diagram
Year of manufacture: 2020, 2021.
Lighter fuse / electrical outlet on Audi A4 and S4 Is fuse #6 (black fuse panel C) in the fuse box in the driver / passenger leg room.
| Color | Amps [A] |
|---|---|
| Black | 1 |
| Purple | 3 |
| Light Brown | 5 |
| Brown | 7,5 |
| Red | 10 |
| Blue | 15 |
| Yellow | 20 |
| White or transparent | 25 |
| Green | 30 |
| Orange | 40 |
Fuse box location
Space for the driver or front passengers.
Vehicles with steering wheel on the left side: Located under the footrest.
Vehicles with the steering wheel on the right side: Behind the lid under the glove box.
Driver’s side fuse box
Luggage compartment
Located on the left side of the luggage compartment behind the trim panel.
Fuse box diagrams
2020
Driver’s legroom (right hand drive)
Front passenger’s legroom (right-hand drive)
Fuse assignment in passenger compartment
| Number | Description |
|---|---|
| Brown panel A | |
| 1 | – |
| 2 | Engine components |
| 3 | Exhaust ports;
Fuel injectors; Radiator inlet; Crankcase cover heater. |
| 4 | Vacuum pump;
Hot water pump; NOx sensor; Particulate matter sensor; Biodiesel sensor; Exhaust port. |
| 5 | Brake light sensor |
| 6 | Engine valves;
Camshaft adjustment |
| 7 | Heated oxygen sensor;
Mass airflow sensor; Water pump. |
| 8 | Water pump;
High pressure pump; High pressure control valve; Temperature valve; Motor mount. |
| 9 | Hot water pump;
Motorized relay. |
| 10 | Oil pressure sensor;
Oil temperature sensor. |
| 11 | Clutch pedal position sensor;
Engine start; Water pump. |
| 12 | Engine valves;
Engine assembly. |
| 13 | Radiator Fan |
| 14 | Fuel injectors;
Engine control module. |
| 15 | Ignition coils;
Heated oxygen sensor. |
| 16 | Fuel Pump |
| Red panel B. | |
| 1 | Anti-theft alarm system |
| 2 | Motor control module |
| 3 | Lumbar support;
Front left seat electronics; Seat massage. |
| 4 | Automatic transmission selection mechanism |
| 5 | Horn |
| 6 | Electromechanical Parking Brake |
| 7 | Gate Control Module |
| 8 | Electronic Air Control Module |
| 9 | Emergency Call System |
| 10 | Airbag control module |
| 11 | Electronic Stability Control (ESC) |
| 12 | Diagnostic connector;
Light and rain sensor. |
| 13 | Air conditioning, heating and ventilation control system |
| 14 | Front right door control module |
| 15 | A/C Compressor |
| Black C-panel | |
| 1 | Front seat heating |
| 2 | Windshield Wipers |
| 3 | Left headlight electronics |
| 4 | Panoramic glass roof / sliding roof / sloping roof |
| 5 | Front left door control module |
| 6 | Plugs |
| 7 | Right Rear Door Control Module |
| 8 | AWD control module |
| 9 | Right Headlight Electronics |
| 10 | Windshield washers;
Headlight washers. |
| 11 | Left rear door control module |
| 12 | Parking Lot Heater |
| Black panel D | |
| 1 | Front seat electronics;
Seat ventilation; Rearview mirror; Rear air conditioning, heating and ventilation control system; Windshield misting; CAN diagnostics. |
| 2 | CAN port
Control system for air conditioning, heating and ventilation. |
| 3 | Tuning the exhaust sound;
Sound actuator. |
| 4 | Clutch pedal position sensor |
| 5 | Starting the engine;
Emergency shutdown. |
| 6 | CAN Port |
| 7 | USB charging port |
| 8 | Homelink (garage door opener) |
| 9 | Adaptive cruise control;
Remote control. |
| 10 | – |
| 11 | Video Camera |
| 12 | Matrix LED Headlight and LED Headlight Right |
| 13 | Matrix LED headlight and LED headlight left |
| 14 | Transmission fluid cooling valve |
| 15 | Warning;
Hands-free kit. |
| Red panel E. | |
| 1 | Ignition coils |
| 2 | Clutch compressor, CNG system |
| 3 | – |
| 4 | – |
| 5 | Left Headlight |
| 6 | Automatic transmission |
| 7 | Dashboard |
| 8 | Air conditioning system (fresh air blower) |
| 9 | Headlight right |
| 10 | Dynamic control |
| 11 | Starting the engine |
Driver’s side cockpit
Fuse assignment in the driver’s side cockpit
| Number | Description |
|---|---|
| 1 | Opening and starting the vehicle (NFC) |
| 2 | Audi Phonebox;
USB port. |
| 3 | – |
| 4 | Main Screen |
| 5 | Audi music interface;
USB charging port. |
| 6 | Front air conditioning controls |
| 7 | Steering column lock |
| 8 | Center view |
| 9 | Instrument cluster |
| 10 | Volume Control |
| 11 | Light Switch |
| 12 | Steering column electronics |
| 13 | Particle sensor for air conditioning system |
| 14 | Infotainment system |
| 15 | – |
| 16 | Steering wheel heating;
Steering column electronics. |
Left boot side
Boot fuse assignment
| Number | Description |
|---|---|
| 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 | Left side rear lights |
| 10 | Airbag module |
| 11 | Electric trunk lid;
Fuel filler flap; Comfort system control module. |
| 12 | Electric trunk lid lock;
Fuel filler flap. |
| 13 | Electric trunk lid. |
| Red panel B. | |
| 6 | Electric compressor |
| Brown panel C | |
| 1 | External Antenna |
| 2 | Audi Phonebox |
| 3 | Lumbar support;
Right side front seat electronics; Seat massage. |
| 4 | Audi Lateral Assistance |
| 5 | – |
| 6 | Tire pressure monitor |
| 7 | Opening and starting the vehicle (NFC) |
| 8 | Parking lot heater radio receiver;
Intelligent module (fuel tank). |
| 9 | – |
| 10 | TV Tuner;
CAN Port. |
| 11 | Auxiliary Battery Module |
| 12 | Homelink (garage door opener) |
| 13 | Reverse Reversing Camera;
Peripheral cameras. |
| 14 | Right rear light |
| 15 | – |
| 16 | Airbag module;
Right seat belt pretensioner. |
| Red panel E. | |
| 1 | – |
| 2 | – |
| 3 | AdBlue |
| 4 | – |
| 5 | Trailer hitch (right light) |
| 6 | – |
| 7 | Towing hook |
| 8 | Trailer hitch (left light) |
| 9 | Towing hitch (socket) |
| 10 | Sport differential |
| 11 | Exhaust gas treatment, AdBlue |
2021
Driver’s legroom (right side steering wheel)
Front passenger’s legroom (right-hand drive)
Fuse assignment in passenger compartment
| Number | Description |
|---|---|
| Brown panel A | |
| 1 | Catalytic converter heating |
| 2 | Engine components |
| 3 | Exhaust ports;
Fuel injectors; Radiator Inlet; Crankcase cover heater. |
| 4 | Vacuum pump;
Hot water pump; NOx sensor; Particulate matter sensor; Biodiesel sensor; Exhaust port. |
| 5 | Brake light sensor |
| 6 | Engine valves;
Camshaft adjustment |
| 7 | Heated oxygen sensor;
Mass airflow sensor; Water pump. |
| 8 | Water pump;
High pressure pump; High pressure control valve; Temperature valve; Motor assembly. |
| 9 | Hot water pump;
Motorized relay. 48 V traction generator; 48V water pump. |
| 10 | Oil pressure sensor;
Oil temperature sensor. |
| 11 | Clutch pedal position sensor;
Engine start; Water pump; 48-volt drive train generator; 12-volt drive train generator. |
| 12 | Engine valves;
Engine assembly. |
| 13 | Engine Cooling |
| 14 | Fuel injectors;
Engine control module. |
| 15 | Ignition coils;
Heated oxygen sensor. |
| 16 | Fuel Pump |
| Red Panel B. | |
| 1 | Anti-theft alarm system |
| 2 | Motor control module |
| 3 | Lumbar support;
Front left seat electronics; Seat massage. |
| 4 | Automatic transmission selection mechanism |
| 5 | Horn |
| 6 | Electromechanical parking brake |
| 7 | CAN port control module |
| 8 | Electronic Air Control Module |
| 9 | Emergency Call System |
| 10 | Airbag control module |
| 11 | Electronic Stability Control (ESC);
ABS. |
| 12 | Diagnostic connector;
Light and rain sensor. |
| 13 | Air conditioning, heating and ventilation control system |
| 14 | Front right door control module |
| 15 | A/C Compressor |
| 16 | Brake system pressure reservoir |
| Black panel C | |
| 1 | Front seat heating |
| 2 | Windshield Wipers |
| 3 | Left-Headlight Electronics |
| 4 | Panoramic glass roof / sliding roof / sloping roof |
| 5 | Front left door control module |
| 6 | Plugs |
| 7 | Right rear door control module;
Right rear window actuator. |
| 8 | AWD control module |
| 9 | Right Headlight Electronics |
| 10 | Windshield washers;
Headlight washers. |
| 11 | Left rear door control module |
| 12 | Parking Lot Heater |
| Black panel D | |
| 1 | Front seat electronics;
Seat ventilation; Rearview mirror; Rear air conditioning, heating and ventilation control system; Windshield misting; CAN diagnostics. |
| 2 | CAN port;
Air conditioning, heating and ventilation control system. |
| 3 | Sound generator |
| 4 | Clutch pedal position sensor |
| 5 | Starting the engine;
Emergency shutdown. |
| 6 | CAN port;
Traffic jam information system (TMC). |
| 7 | USB charging port |
| 8 | Homelink (garage door opener) |
| 9 | Adaptive cruise control;
Remote control. |
| 10 | – |
| 11 | Video Camera |
| 12 | Matrix LED Headlight and LED Headlight Right |
| 13 | Matrix LED headlight and LED headlight left |
| 14 | Transmission fluid cooling valve |
| 15 | Warning;
Hands-free kit. |
| Red panel E. | |
| 1 | Ignition coils |
| 2 | A/C Compressor |
| 3 | – |
| 4 | – |
| 5 | Left Headlight |
| 6 | Automatic transmission |
| 7 | Dashboard |
| 8 | Air conditioning system (fresh air blower) |
| 9 | Headlight right |
| 10 | Dynamic control |
| 11 | Starting the engine |
Driver’s side cockpit
Fuse assignment in the driver’s side cockpit
| Number | Description |
|---|---|
| 1 | Opening and starting the vehicle (NFC) |
| 2 | Phone;
Mobile Device Charger. |
| 3 | – |
| 4 | Main Screen |
| 5 | Audi music interface;
USB charging port. |
| 6 | Front air conditioning controls |
| 7 | Steering column lock |
| 8 | Infotainment system visualization |
| 9 | Instrument cluster |
| 10 | Information and Entertainment Unit |
| 11 | Light Switch |
| 12 | Steering Column Electronics |
| 13 | Particle sensor for the air conditioning system |
| 14 | Infotainment System |
| 15 | – |
| 16 | Steering wheel heating |
Left boot side
Boot fuse assignment
| Number | Description |
|---|---|
| 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 | Left Side Rear Lights |
| 10 | Airbag module |
| 11 | Central locking system |
| 12 | Electric trunk lid;
Fuel filler flap. |
| Red panel B. | |
| 6 | Electric compressor;
Battery power cut. |
| Brown panel C | |
| 1 | – |
| 2 | Phone;
Mobile device charging function – USB. |
| 3 | Lumbar support;
Right front seat electronics; Seat Massage. |
| 4 | Audi Lateral Assistance |
| 5 | – |
| 6 | Tire pressure monitor |
| 7 | Opening and starting the vehicle (NFC) |
| 8 | Parking lot heater radio receiver;
Intelligent module (fuel tank). |
| 9 | – |
| 10 | TV Tuner;
CAN Port. |
| 11 | Auxiliary Battery Module |
| 12 | Homelink (garage door opener) |
| 13 | Reverse Reversing Camera;
Peripheral cameras. |
| 14 | Right taillights |
| 15 | – |
| 16 | Airbag system |
| Red panel E. | |
| 1 | – |
| 2 | – |
| 3 | AdBlue |
| 4 | – |
| 5 | Trailer hitch (right light) |
| 6 | – |
| 7 | Towing hook |
| 8 | Trailer hitch (left light) |
| 9 | Towing hitch (socket) |
| 10 | Sports differential;
4-wheel drive. |
| 11 | Exhaust gas treatment, AdBlue |
