Fuses and relays Audi A4 B9 (W8), 2015 – 2024. Fuse diagram Audi A4 B9 (W8), 2015 – 2024.

Audi A4 (B9) is the fifth generation of the mid-size sedan and station wagon from the German manufacturer. The official premiere took place in September 2015 at the International Motor Show. In this material, we will analyze in detail the fuse diagrams of the Audi A4 B9 (fifth generation; MLB Evo platform; body style W8) 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024 models.

Here you will find the locations and photos of the mounting blocks. We would like to separately note the fuses responsible for the cigarette lighter and the fuel pump.

General arrangement of electronic modules:
1. Relay and fuse block 2 -SR2-
2. Unit -TV1- (for models with 48-volt hybrid system)
3. Main fuse block on battery -A- (not for models with CNG engine)
4 – Unit 2 for models 4
5. Fuse block C-SC- (at the end of the dashboard)
6. Relay and fuse block 1 -SR1- with fuse holder B -SB-
7. Main fuse block on battery -A- (only for models with CNG engine)
8. Relay and fuse block 3 -SR3- / . -SR4-
10.
Connector for connection to terminal 40 -TV66- (for models with 48-volt hybrid system)
11. Fuse block A -SA-

Main fuses -A- on the battery

The installation location differs from the type of engine installed

All engines except CNG

Located in the trunk on the battery.

A. | To fuse and relay block 2 -SR2- (holder -SF-) | 80A
B. | To power steering control unit -J500- | 125A
C. | To positive terminal B302 6(30) in main wiring harness | 150A
D. | To B272 positive connection (30) in main wiring harness and B298 positive connection 2 (30) in main wiring harness | 200A

With CNG engine

Description:
A. | to power steering control unit -J500- | 125A
B. | Power supply for terminal 30 of the wiring of the splitter 3-TV28- | 300A
C. | not assigned
D. | Power supply for the windshield heater -Z2- | 70A
E. | Power supply for unit 1-SR1-(holder-SB-) | 200A
F. | Power supply for unit 2-SR2-(holder-SF-) | 150A

Unit -TV1-(hybrid engines; in the trunk)

Installed on vehicles with a 48-volt hybrid system.

A. | Fuse 4 on connection unit -S374 – to voltage converter, 48V/12V -A7- | 300A
B. | not assigned
C. | Fuse 2 on mounting unit -S372-, to unit 2-SR2- | 70A
D. | not assigned
E. | Connection to terminal 30 from fuse holder -S-.

Unit -TV67-(hybrid engines; in the trunk)

Installed on vehicles with a 48-volt hybrid system. 

A. | Connection of terminal 40 from connector -TV66-. terminal 40  
B. | Connection of terminal 40 to battery, 48 V -A6-
C. Fuse 1 on mounting assembly 2 for terminal 40 -S368-, to voltage converter, 48 V/12 -A7- | 125A
D. | Not assigned
E. | not assigned

Block 2 -SR2- (holder -SF-; in the luggage compartment)

This fuse box is located on the left side of the luggage compartment. To access it, you must remove part of the trim.

Access example.

General appearance.

Scheme
No.	Description	Current, A
R1	Right side windshield heating relay -J411-
R1	Two-way radio voltage relay 2 -J888- *only for special vehicles*
R2	Two-way radio voltage relay -J84- *only for special vehicles*
R3	Two-way radio voltage relay -J84-*only for special vehicles*
R4.1	Left side windshield heating relay -J410-
R4.2	Right side windshield heating relay -J411-
R5	Digital Audio Package Fuse S358-40A (From July 2019)	40A
A	Fuse for heated rear window -S41- , 40 A	40A
A	Automatic transmission control unit fuse -S113- *not for natural gas vehicles*	50A
B	Heating element fuse 1 -S291-	15A
C	Front passenger seat adjustment thermal fuse 1 -S46-	15A
D	Terminal 30 fuse, trailer towing bracket -S77- *only for Australian models and only for models with US equipment*	30A
ST1 panel, black
1	Empty
2	Right side windscreen heating relay -J411- and Windscreen heating -Z2-	35A
3	Left side windscreen heating relay -J410- and Windscreen heating -Z2-	35A
4	Empty
5	Chassis control unit -J775	15A
6	Automatic transmission control unit -J217-6) and Selector lever-E313-2)	15A 6) / 7.5A 2)
7	Rear window heating relay -J9-3)	30A
8	Control and display unit for the air conditioning system in the rear of the passenger compartment -E265	30A
9	Central control unit for comfort system -J393-4); Power supply: left rear lights -MX3-	20A
10	Front left seat belt tensioner control unit -J854-	25A
11	Central control unit for comfort system -J393-5); Power supply: rear center light and left rear light 2-MX5-, right rear light 2-MX6-	20A
12	Rear cover control unit -J605	30A
Note: 1) Depending on equipment 2) For models with gas engine 3) Only for Avant models 4) (T17a/16), 5) (T17a/17), 6) not for natural gas vehicles
ST3 panel, brown
1	Empty
2	Aerodynamic amplifier for mobile phone -R86	5A
3	Front passenger multi-contour seat control unit -J872-, Front right seat lumbar support adjustment switch -E753-, Front passenger seat lumbar support longitudinal adjustment motor -V126-. Front passenger seat lumbar support height adjustment motor -V130-	7.5A
4	Lane change assist control unit	5A
5	Rear information displays and control panels control unit	10A
6	Tire pressure monitoring system control unit -J502-	5A
7	Close-range control unit 2 -J1170-, Close-range control unit -J1169-	5A
8	Auxiliary heater remote control receiver -R64-, Metering pump -V54-, Fuel tank leak detection control unit -J909-	5A
9	Empty
10	TV tuner -R78-	5A
11	48 V battery -A6-, Second battery -A1-, Connection point in the passenger compartment -TI- (/3)	10A
12	Garage door control unit -J530-, Garage door control unit -E284-	5A
13	Reversing camera system control unit -J772-, Overhead camera control unit -J928-	5A
14	Central convenience control unit -J393-, (T17b/16) Power supply: Right rear light -MX4-	20A
15	Empty
16	Front right seat belt tensioner control unit	25A
ST5 panel, red
1	Empty
2	Digital sound package control unit -J525-	30A
3	Reductant dosing system control unit -J880-	30A
4	Empty
5	Trailer detector control unit -J345	25A
6	Empty
7	Trailer detector control unit -J345	15A 1) / 20A 2)
8	Trailer detector control unit -J345-	25A
9	Trailer detector control unit -J345-	15A 1) / 20A 2)
10	Differential lock control unit -J187	40A
11	Reductant dosing system control unit -J880-	25A
12	Empty
ST6 panel, black
1	Positive connection 8 (30a) in the vehicle’s special wiring harness -X227-	5A
2	Socket 12V-U5-	15A
3	12V socket #2 -U18-	15A
4	12V socket #3 -U19-	15A
5	Two-way radio voltage relay -J84-	10A
6	Two-way radio voltage relay -J84-	10A
7	Two-way voltage relay 2 -J888-	10A
8	Two-way radio voltage relay 2 -J888-	10A
9	Positive connector 4 (30a) in the special vehicle wiring harness -X223-	5A
10	Positive contact 2 (58) in the special vehicle wiring harness -A251-	10A
11	Connection point in the luggage compartment, center -THRM-, pin 16	5A
12	Positive contact 3 (30a) in the special vehicle wiring harness -X222-	7.5A
13	Special vehicle control unit -J608-, pin 18	1A
14	Empty
15	Connection point in the luggage compartment (right -THRR-), Control unit for the turning light and siren system -J23-	20A
16	Empty

Block C-SC-(in the cabin)

Located at the end of the instrument panel on the driver’s side.

General appearance.

Scheme
No.	Description	Current, A
1	Empty	–
2	Chip card reader control unit -J676-, Telephone bracket -R126-	5A
3	Empty	–
4	Main display control unit -J898-	5A
5	Connector for connecting external sound sources -R199-	5A
6	Front air conditioning control and display unit -E87-, Heater control unit -J65-	10A
7	Electronic steering column lock control unit -J764-	10A
8	Display unit for front information display and control unit for control panel -J685-	10A 3) / 5A 3)
9	Control unit in instrument panel insert -J285-	10A
10	Multimedia system control unit -E380-	5A
11	Light switch -E1-, Control unit 1 for driving and comfort functions -E791-	5A
12	Steering column electronics control unit -J527-	1A
13	Empty	–
14	Control unit 1 for information electronics -J794-	20A 1) / 5A 2)
15	Empty
16	Steering column electronics control unit -J527-, Heated steering wheel -Z36-	10A
Note: 1) 8RM sound system, 2) 9VS and 8RF sound system, 3) Depending on equipment

Block 1-SR1-(holder-SB-; in the cabin)

Located in the lower part of the instrument panel, at the driver’s feet. The purpose of the fuses on the panel may vary depending on the installed engine. Only left-hand drive models are considered.

General appearance.

Scheme
No.	Description	Current, A
A	ABS control unit 1 -S123- and ABS control unit 2 -S124-	40A
B	Automatic transmission control unit fuse -S113- (For models with natural gas engine)	50A
C	Driver’s seat adjustment thermal fuse 1-S44-	15A
ST1 panel   , brown (  diesel engines  )
1	Empty
2	Exhaust cam drive 1 for cylinders 1-6 1)	15
3	Radiator shutter control motor -V544-2); Radiator shutter control motor 2-V550-2)	5
4	NOx sensor control unit -GX30-, NOx sensor -G295-, NOx sensor control unit -J583-, NOx sensor control unit 2 -GX46-, NOx sensor 2 -G687-, NOx sensor control unit 2 -J881-, biodiesel concentration sensor -G855- 7), Sensor 881- 3), Coolant circulation pump -V50-	5A 2) / 10A 3) / 15A 9)
5	Brake light switch -F-	5
6	Boost pressure control solenoid valve -N75- 2), Oil pressure control valve -N428- 2), Cylinder head coolant valve -N489-, Left electro-hydraulic engine mount solenoid valve -N144- 2), Right electro-hydraulic engine -J179- 3), Engine cooling system thermostat with map control -F265- 4), Camshaft adjustment drive 1 -F366- 8), Camshaft adjustment drive 2 -F367- 8), Coolant circulation pump – 345-3) 5), Oil pressure control valve -N428-9), Piston cooling jet control valve-N522-9)	10A 1) 9) 3) / 5A 2) / 7.5A 4)
7	Air mass meter -G70-, Engine control unit -J623-3), Crankcase breather heater -N79-2), Coolant switching valve 2-N633-9), Charge air cooling pump -V188-9)	5A 2) 3) / 10A 9)
8	Fuel pressure control valve -N276-, Fuel metering valve -N290-, Coolant circulation pump -V50-, Radiator shutter control motor -V544	10A
9	Engine component power supply relay -J757-, Starter alternator -C29-8), Starter alternator coolant pump -V621-8), Electric compressor control unit -J1123-8)	5A
10	Oil level and temperature sensor -G266-, Crankcase breather heater -N79- 9)	5A
11	Clutch position sensor -G476-, Starter alternator -C29-9)	5A
12	Camshaft adjustment drive 1 -F366-, Camshaft adjustment drive 2 -F367-, Air filter bypass valve flap -N275-, Charge air temperature sensor in front of charge air cooler -G810- 1), Engine mounting circulation pump valve -N144 – 3), Right electro-hydraulic engine mounting solenoid valve – N145 – 3), Auxiliary heating pump – V488 – 2), Automatic glow period control unit – J179 – 2), Charge air cooling pump – V18	5A / 9) 7.5A 3) / 10A 2)
13	Radiator fan -VX57-, Radiator fan control unit -J293-, Radiator fan control unit 2 -J671-6)	5A
14	Engine control unit -J623-	15A
15	Lambda probe 1 in front of catalytic converter -GX10-, Lambda probe heater -Z19-	10A
16	Fuel pump control unit -J538-	25A 2) / 30A3)
Note: 1) DCPC, DCPE only 2) 4-cylinder models only 3) 6-cylinder models only 4) CRTC, DCPC, DCPE only 5) American markets only 6) models with towbar only 7) models with Euro 5 plus (7M) emission standard only
ST1 panel   , brown (  models with 4-cylinder petrol engine)
1	Empty	–
2	Empty	–
3	Empty	–
4	Circulation pump -V55-2), Continuous coolant circulation pump -V51-3)	5A
5	Brake light switch -F-	5A
6	Actuators 1 – 8 for camshaft adjustment 4) 5), Piston cooling jet control valve -N522-	15A
7	Lambda probe 1 after catalytic converter -GX7-1) 4) 5), Lambda probe 1 before catalytic converter -GX10-1)	15A
8	Left electro-hydraulic engine mounting solenoid valve -N144- 7), Charge air cooling pump -V188- 1), Right electro-hydraulic engine mounting solenoid valve -N145- 2) 7), Coolant circulation pump -V18-	15A 1) / 5A 2)
9	Circulation pump -V55-1), Engine component power supply relay -J757-2)	5A
10	Oil level and temperature sensor -G266-	5A
11	Clutch position sensor-G476-, Starter generator-C29-8)	5A
12	Solenoid valve for charcoal filter 1 -N80-, Secondary air intake valve -N112- 5), Camshaft control valve 1 -N205-, Turbocharger air recirculation valve -N249- 2), Intake manifold flap valve -N316-3) , Oil pressure control valve -N428-, Piston cooling jet control valve -N522- 2), Camshaft adjustment actuators 1 – 8 3) 6)	15A 1) / 10A 2)
13	Radiator fan -VX57-	5A
14	Engine control unit -J623-, Injector 2 for cylinder 1-N532-3) 4), Injector 2 for cylinder 2-N533-3) 4), Injector 2 for cylinder 3-N534-3) 4), Injector 2 for cylinder 4-3	15A
15	Lambda probe 1 before catalytic converter -GX10- 2), Lambda probe 1 after catalytic converter -GX7- 3) 6), Ignition coil 1 with output stage -N70- 1), Ignition coil 2 with output stage 91-1), Ignition coil 4 with output stage -N292-1)	20A 1) / 15A 2)
16	Fuel pump control unit -J538-, fuel pump fuse Audi A4 B9	25A
Note: 1) only with 1.4L petrol engine 2) only with 2.0L petrol engine 3) CVKB 4) CYRB, CYRC 5) CYMC 6) DBPC 7) automatic transmission only
ST1 panel   , brown  (models with 6-cylinder petrol engine)
1	Empty
2	Empty
3	Empty
4	Exhaust gas flap control unit -J883-, Exhaust gas flap control unit 2 -J945-	7.5A
5	Brake light switch -F	5A
6	Left and right electro-hydraulic engine mount solenoid valve -N144- and -N145-, Charcoal filter solenoid valve 1 -N80-, Excess air recirculation valve for bank 1 -N625-, Intake cam actuator 1 for cylinder 1 -F442-, Intake cam actuator 1 for cylinder 3 -F456-, Intake cam actuator 1 for cylinder 4 -F460-	10A
7	Lambda sensor 1 after catalytic converter -GX7-	15A
8	Intake cam drive 1 for cylinder 5 -F464-, Intake cam drive 1 for cylinder 6 -F468-, Engine cooling system thermostat with map control -F265-	15A
9	Engine component power supply relay -J757-	5A
10	Oil level and temperature sensor -G266-	5A
11	Empty
12	Boost pressure control solenoid valve -N75-, Camshaft control valve 1 -N205-, Camshaft control valve 2 -N208-, Exhaust camshaft control valve 1 -N318-, Exhaust camshaft control valve 2 -N319-	15A
13	Radiator fan -VX57-	5A
14	Engine control unit -J623-	15A
15	Lambda sensor 1 in front of catalytic converter -GX10-	15A
16	Fuel pump control unit -J538-,   fuel pump fuse	30A
ST1 panel   , brown (  cars with 2.0 l CNG engine  )
1	Empty
2	Empty
3	Empty
4	Circulation pump -V55-	5A
5	Brake light switch -F-	5A
6	Empty
7	Empty
8	Left electro-hydraulic engine mounting solenoid valve -N144-, Right electro-hydraulic engine mounting solenoid valve -N145-, Coolant circulation pump -V50-, Radiator shutter control motor -V544-	7.5A
9	Engine component power supply relay -J757-	5A
10	Oil level and temperature sensor -G266-	5A
11	Empty
12	Solenoid valve for charcoal filter 1 -N80-, Camshaft control valve 1 -N205-, Exhaust camshaft control valve 1 -N318-, 522-, Camshaft adjustment actuator 1 -F366-, Camshaft adjustment actuator 2 -F368-, Camshaft adjustment actuator 4 Camshaft adjustment actuator 6 -F371-, Camshaft adjustment actuator 7 -F372-, Camshaft adjustment actuator 8 -F373-	15A
13	Radiator fan -VX57-	5A
14	Engine control unit -J623-, Gas injection valves 1-2-3-4	15A
15	Lambda probe 1 before catalytic converter-GX10-, Lambda probe 1 after catalytic converter-GX7-	15A
16	Fuel pump control unit -J538-, fuel pump fuse	25A
ST2 panel   , red
1	Anti-theft alarm sensor -G578-, Alarm signal -H12-	5A
2	Main relay -J271-, Engine control unit -J623	5A
3	Front left seat lumbar support adjustment switch -E752-, Driver’s seat lumbar support longitudinal adjustment motor -V125-, Driver’s seat lumbar support height adjustment motor -V129-	7.5A
4	Selector lever -E313-	7.5A
5	On-board power supply control unit -J519-, (T73b/12) Power supply: High-frequency horn -H2- and Low-frequency horn -H7-	15A
6	Electromechanical parking brake button -E538-	5A
7	Data bus diagnostic interface -J533-	5A 1) / 10A 2)
8	Roof electronics control unit -J528-, Front roof module -WX3-	5A
9	Airbag control unit -J234-	5A
10	Empty
11	ABS control unit -J104-	5A
12	Temperature and light sensor -G397-, Light sensor -G399-, Diagnostic connector -U31-	10A
13	On-board power supply control unit -J519-, (T73a/2) Power supply: air conditioning: Magnetic clutch for air conditioning system -N25-, Air conditioning compressor control valve -N280-	20A
14	Front passenger door control unit -J387-	20A
15	On-board power supply control unit -J519-, (T73a/12) Power supply: interior lighting: Rear interior light -WX2- Front roof module -WX3-	20A
16	Empty
Note: 1) until May 2016; 2) from June 2016
ST3 panel   , black
1	On-board power supply control unit -J519-, (T73b/73) Power supply: Seat heating, Rear left seat cushion heating -Z11-, Seat heating -Z45-, Front right seat cushion heating -Z46-, Front left seat backrest heating -Z116-, Front right seat backrest heating -Z117-	30A
2	Wiper motor control unit -J400-	30A
3	On-board power supply control unit -J519-, (T73a/66) Power supply: left front headlights, Left front headlight -MX1-	30A
4	Sliding sunroof control unit -J245-	20A 1) / 30A 2)
5	Driver’s door control unit -J386-	20A
6	On-board power supply control unit -J519-, (T73a/73) Power supply:  Cigarette lighter  -U1- or 12V connector	20A
7	Door control unit on the rear passenger side -J927-	20A
8	All-wheel drive control unit -J492-	15A
9	On-board power supply control unit -J519-, (T73b/66) Power supply: right front headlights, right front headlight -MX2-	30A
10	On-board control unit -J519-, (T73b/1) Supply: Washer pump -V5-, Headlight washer pump -V11-, Left washer nozzle heating element -Z20-, Right washer nozzle heating element -Z21-	35A
11	Door control unit on the rear driver’s side -J926-	20A
12	Auxiliary heater control unit -J364-	30A
Note: 1) Sedan only; 2) Not for Sedan
ST4 panel   , black
1	Diagnostic connection -U31-, High beam assist control unit -J844-, Seat and steering column adjustment control unit with memory -J136-, Rear air conditioning control and display unit -E265-, Windscreen heating relay -J44-, Windscreen heating for right side -J411-	5A
2	Data bus diagnostic interface -J533-, On-board power supply control unit -J519-, (T73a/7) Power supply: parking aid system (Park Distance Control – PDC)	10A
3	Design-transmitted sound control unit -J869-, Engine sound generator control unit -J943-	5A
4	Clutch position sensor G476-	5A
5	Starter relay 1-J906-, Starter relay 2-J907-	5A
6	Empty
7	USB charging socket 2 -U38-	5A
8	Garage door control unit -E284-	5A
9	Adaptive cruise control unit -J428-, Control unit 2 for adaptive cruise control -J850-	10A
10	Driving school mode relay -J746-, Connection point on left A-pillar -TAL-, T4fh/4
11	Front camera for driver assistance systems -R242-	7.5A
12	Front right headlight -MX2-	10A
13	Front left headlight -MX1-	10A
14	Rear window wiper motor -V12-	20A
15	Empty
16	Empty
ST5 panel   , red
1	Ignition coils (1, 2, 3, 4) with output stage 1) 2)	20A
2	High pressure valve for gas mode -N372-2), Fuel tank shut-off valves 2)	10A
3	Empty
4	Empty
5	Empty
6	Auxiliary hydraulic pump 1 for transmission oil -V475-	15A
7	Power supply for fuse block C-SC-	40A
8	Fresh air fan control unit -J126-	30A
9	Empty
10	Active steering control unit -J792-	40A
11	Starter relay 2 -J907-, Starter relay 1 -J906- / Starter -B- fuse (50) -S216-	35A
12	Special vehicle control unit -J608-, T12o/10, T12o/12 Connection point on left A-pillar -TAL-, T4fh/1	10A
Note: 1) Only with 2.0L petrol engine; 2) Only with 2.0L CNG engine
Relay modules   in the unit: R1 – Relay for supplying current to engine components -J757- R2 – Main relay -J271- R3 – Relay for supplying voltage to terminal 15 -J329-

Block 4-SR4-(inside)

Located near the front passenger’s rack.

A. | Heating element fuse 2-S277-| 70 A
B. | Heating element fuse 1-S276-| 40
R1. | Low heat output relay -J359-
R2. | High heat output relay -J360-

Block 3-SR3-(in the engine compartment)

Located near the windshield in the center of the engine compartment.

Description:
R1.1. | not assigned
R1.2. | Fuse (50)-S216-, 5A, to engine control unit-J623-
R2. | Starter relay 1-J906-
R3. | Starter relay 2-J907-

Block 5-SR5-(in the engine compartment)

Located near the windshield, in the center of the engine compartment.

Description:
A. | Fuse 1 in holder -S1-, 35A
B. | Fuse 2 in holder -S2-, 35A
R1. | Left side windscreen heating relay-J410-
R2. | Right side windscreen heating relay-J411-

Block A-SA-(in the engine compartment)

Description:
1. | Fuse holder A-SA-
2. Interference filter -C24-
A. | 50 A, radiator fan control unit 2 -J671- | 50A
B. | to radiator fan control unit -J293-| 50A/70A (depending on equipment)
C. | diesel to automatic glow plug control unit -J179- | 80A (4-cylinder engine) / 125A (6-cylinder engine)
D. | Separate radiator fan fuse -S42-| 50A (depending on equipment) / 70A (6-cylinder engine) *only for vehicles with petrol engine and radiator fan*.

Unit -TV66-(hybrid engines; in the engine compartment)

Installed on vehicles with a 48-volt hybrid system. 

A. | Connection terminal 40 to connector 2-TV67-in the luggage compartment.
B. | Connection terminal 40 from starter -C29-
C. Fuse 1 on terminal 40 -S366-, to electric compressor control unit
-J1123-| 150 A