Audi A4 and S4 B9/8W – fuse box diagram
Year of manufacture: 2020, 2021.
Cigarette lighter / electrical socket fuse in Audi A4 and S4. is fuse No. 6 (black fuse panel C) in the fuse box in the driver / passenger legroom.
| 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 |
Location of fuse box
Driver or front passenger legroom.
Vehicles with steering wheel on left side: Located under the footrest.
Vehicles with the steering wheel on the right side: Behind the cover under the glove box.
Driver side fuse box
Luggage compartment
Located on the left side of the trunk behind the trim panel.
Fuse box diagrams
2020
Driver’s legroom (steering wheel on right side)
Front passenger legroom (steering wheel on right side)
Assignment of fuses in the passenger compartment
| Number | Description |
|---|---|
| Brown panel A | |
| 1 | – |
| 2 | Engine components |
| 3 | Exhaust doors;
Fuel injectors; Radiator inlet; Crankcase cover heater. |
| 4 | Vacuum pump;
Hot water pump; NOx sensor; Particulate sensor; Biodiesel sensor; Exhaust door. |
| 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; Engine mount. |
| 9 | Hot water pump;
Motor 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 | Engine control module |
| 3 | Lumbar support;
Left front seat electronics; Seat massage. |
| 4 | Automatic transmission selection mechanism |
| 5 | Horn |
| 6 | Electromechanical parking brake |
| 7 | Gate control module |
| 8 | Overhead electronic 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 | Right front 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/tilting roof |
| 5 | Left front door control module |
| 6 | Sockets |
| 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 heater |
| Black panel D | |
| 1 | Front seat electronics;
Seat ventilation; Rear view mirror; Rear air conditioning, heating and ventilation control system; Windshield defogger; CAN diagnostics. |
| 2 | CAN gateway
Control system for air conditioning, heating and ventilation. |
| 3 | Exhaust sound tuning;
Sound actuator. |
| 4 | Clutch pedal position sensor |
| 5 | Engine start;
Emergency shutdown. |
| 6 | CAN gateway |
| 7 | USB charging port |
| 8 | Homelink (garage door opener) |
| 9 | Adaptive Cruise Control;
Distance control. |
| 10 | – |
| 11 | Video camera |
| 12 | Matrix LED headlight and right LED headlight |
| 13 | Matrix LED headlight and left LED headlight |
| 14 | Transmission fluid cooling valve |
| 15 | Alert;
Hands-free kit. |
| E red panel. | |
| 1 | Ignition coils |
| 2 | Compressor clutch, CNG system |
| 3 | – |
| 4 | – |
| 5 | Left headlight |
| 6 | Automatic transmission |
| 7 | Instrument panel |
| 8 | Air conditioning system (fresh air blower) |
| 9 | Right headlight |
| 10 | Dynamic control |
| 11 | Engine start |
Driver side cockpit
Driver-side cockpit fuse assignment
| Number | Description |
|---|---|
| 1 | Vehicle opening and starting (NFC). |
| 2 | Audi Phonebox;
USB port. |
| 3 | – |
| 4 | Head-up display |
| 5 | Audi music interface;
USB charging port. |
| 6 | Front air conditioning controls |
| 7 | Steering column lock |
| 8 | Central display |
| 9 | Instrument cluster |
| 10 | Volume control |
| 11 | Light switch |
| 12 | Steering column electronics |
| 13 | Particulate matter sensor for air conditioning system |
| 14 | Infotainment system |
| 15 | – |
| 16 | Steering wheel heating;
Steering column electronics. |
Left side of the trunk
Trunk fuse allocation
| 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 | Rear lights on the left side |
| 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. |
| Panel red B. | |
| 6 | Electric compressor |
| Brown panel C | |
| 1 | External antenna |
| 2 | Audi Phonebox |
| 3 | Lumbar support;
Right front seat electronics; Seat massage. |
| 4 | Audi Side Assist |
| 5 | – |
| 6 | Tire pressure monitor |
| 7 | Opening and starting the vehicle (NFC) |
| 8 | Parking heater radio receiver;
Smart module (fuel tank). |
| 9 | – |
| 10 | TV Tuner;
CAN gateway. |
| 11 | Auxiliary battery module |
| 12 | Homelink (garage door opener) |
| 13 | Reversing camera;
Peripheral cameras. |
| 14 | Right taillights |
| 15 | – |
| 16 | Airbag module;
Right seat belt pretensioner. |
| E red panel. | |
| 1 | – |
| 2 | – |
| 3 | AdBlue |
| 4 | – |
| 5 | Trailer hitch (right light) |
| 6 | – |
| 7 | Towing hook |
| 8 | Trailer hitch (left light) |
| 9 | Trailer hitch (socket) |
| 10 | Sport differential |
| 11 | Exhaust gas treatment, AdBlue |
2021
Driver’s legroom (right side steering wheel)
Front passenger legroom (steering wheel on right side)
Assignment of fuses in the passenger compartment
| Number | Description |
|---|---|
| Brown panel A | |
| 1 | Catalyst heating |
| 2 | Engine components |
| 3 | Exhaust doors;
Fuel injectors; Radiator inlet; Crankcase cover heater. |
| 4 | Vacuum pump;
Hot water pump; NOx sensor; Particulate sensor; Biodiesel sensor; Exhaust door. |
| 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; Engine mount. |
| 9 | Hot water pump;
Motor relay. 48 volt drive train 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 | Engine control module |
| 3 | Lumbar support;
Left front seat electronics; Seat massage. |
| 4 | Automatic transmission selection mechanism |
| 5 | Horn |
| 6 | Electromechanical parking brake |
| 7 | CAN gate control module |
| 8 | Overhead electronic 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 | Right front 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/tilting roof |
| 5 | Left front door control module |
| 6 | Sockets |
| 7 | Right rear door control module;
Right rear window actuator. |
| 8 | AWD (4-wheel drive) control module. |
| 9 | Right headlight electronics |
| 10 | Windshield washers;
Headlight washers. |
| 11 | Left rear door control module |
| 12 | Parking heater |
| Black panel D | |
| 1 | Front seat electronics;
Seat ventilation; Rear view mirror; Rear air conditioning, heating and ventilation control system; Windshield defogger; CAN diagnostics. |
| 2 | CAN gateway;
Air conditioning, heating and ventilation control system. |
| 3 | Sound generator |
| 4 | Clutch pedal position sensor |
| 5 | Engine start;
Emergency shutdown. |
| 6 | CAN gateway;
Traffic jam information system (TMC). |
| 7 | USB charging port |
| 8 | Homelink (garage door opener) |
| 9 | Adaptive Cruise Control;
Distance control. |
| 10 | – |
| 11 | Video camera |
| 12 | Matrix LED headlight and right LED headlight |
| 13 | Matrix LED headlight and left LED headlight |
| 14 | Transmission fluid cooling valve |
| 15 | Alert;
Hands-free kit. |
| E red panel. | |
| 1 | Ignition coils |
| 2 | A/C compressor |
| 3 | – |
| 4 | – |
| 5 | Left headlight |
| 6 | Automatic transmission |
| 7 | Instrument panel |
| 8 | Air conditioning system (fresh air blower) |
| 9 | Right headlight |
| 10 | Dynamic control |
| 11 | Engine start |
Driver side cockpit
Driver-side cockpit fuse assignment
| Number | Description |
|---|---|
| 1 | Vehicle opening and starting (NFC). |
| 2 | Phone;
Mobile device charger. |
| 3 | – |
| 4 | Head-up display |
| 5 | Audi music interface;
USB charging port. |
| 6 | Front air conditioning controls |
| 7 | Steering column lock |
| 8 | Infotainment system display |
| 9 | Instrument cluster |
| 10 | Infotainment unit |
| 11 | Light switch |
| 12 | Steering column electronics |
| 13 | Particulate matter sensor for air conditioning system |
| 14 | Infotainment system |
| 15 | – |
| 16 | Steering wheel heater |
Left side of the trunk
Trunk fuse allocation
| 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 | Rear lights on the left side |
| 10 | Airbag module |
| 11 | Central locking system |
| 12 | Electric trunk lid;
Fuel filler flap. |
| Red panel B. | |
| 6 | Electric compressor;
Battery power cutoff. |
| Brown panel C | |
| 1 | – |
| 2 | Phone;
Mobile device charging function – USB. |
| 3 | Lumbar support;
Right front seat electronics; Seat massage. |
| 4 | Audi Side Assist |
| 5 | – |
| 6 | Tire pressure monitor |
| 7 | Opening and starting the vehicle (NFC) |
| 8 | Parking heater radio receiver;
Smart module (fuel tank). |
| 9 | – |
| 10 | TV Tuner;
CAN gateway. |
| 11 | Auxiliary battery module |
| 12 | Homelink (garage door opener) |
| 13 | Reversing camera;
Peripheral cameras. |
| 14 | Right taillights |
| 15 | – |
| 16 | Airbag system |
| E red panel. | |
| 1 | – |
| 2 | – |
| 3 | AdBlue |
| 4 | – |
| 5 | Trailer hitch (right light) |
| 6 | – |
| 7 | Towing hook |
| 8 | Trailer hitch (left light) |
| 9 | Trailer hitch (socket) |
| 10 | Sport differential;
4-wheel drive. |
| 11 | Exhaust gas treatment, AdBlue |
The article Audi A4 and S4 B9/8W (2020-2021) – fuse box comes from the site Fuseów schematics.