Symbols used in electrical equipment diagrams (Audi A2)

The most important terminals

Terminal 15 (Ignition switch "ON" position)

Receives power through the ignition switch. The wires only supply power when the ignition is on and are usually green or green with a stripe of another color.

Terminal 30 ("+" battery)

This terminal supplies power to the battery; is in most cases red in color or red with a stripe of another color.

Terminal 31 ("-" battery)

Leads to ground. Wires are usually black.

Terminal X

It is energized when the ignition switch is turned from the "LOCK" position to the "OFF" position and is de-energized when the key is turned to the "LOCK" position.

Designation of electrical wiring connectors

On electrical equipment diagrams, connectors are designated as TXXYY, where XX is a number indicating the number of connector contacts, and YY is an auxiliary letter designation.

Electrical wiring designation

The wire designation on the diagrams consists of 3 parts and looks like 1.5 BL/GN. The first part (1.5) means the wire cross-section (mm/'sq.); the second/third parts (BL/GN) mean the main color/color of the wire insulation stripe:

• bl - Blue
• br - Brown
• ge - Yellow
• gn - Green
• gr - Gray
• li - Violet
• or - Orange
• ro - Red
• sw - Black
• ws - White

List of electrical components

Main components of electrical equipment

• A. Battery
• A1. Additional battery
• B. Starter
• C. Generator
• C1. Voltage regulator
• D. Ignition switch
• 01. Immobilizer reading unit
• P. Spark plug connectors
• Q. Spark plugs
• Q10-Q13. Glow plugs No.1-No. 4
• R. Audio block
• R47. Antenna for single lock and anti-theft alarm system, at the bottom of the A-pillar
• TV2. Wiring connection terminal 30

Ground connection points

• 12. In the engine compartment, on the left
• 13. In the engine compartment, on the right
• 42. Near the steering column
• 50/51. Left/right in the trunk
• 77/78. Lower part of left/right B-pillar
• 95. Ground point 1, in seat position adjustment wiring
• 114. In the automatic transmission wiring
• 136/145. Leaks of ground 2/3, in the seat heating wiring
• 205/206. In the driver's/front passenger's door wiring
• 207/208. In the rear left/right door wiring
• 218/219. Ground points 1/2, in the trunk lid wiring
• 238/249. Ground points 1/2, in the passenger compartment wiring
• 277-279. Ground points 3-5, in the interior wiring
• 283. Ground point 2, in the engine compartment wiring
• 286/294/295. Ground points 8/9/10, in the interior wiring
• 306. Connection to ground of ignition coils, in engine wiring
• 345. In the bumper wiring
• 347. In the ceiling wiring
• 367-369. Ground points 2-4, in the main wiring harness
• 371-374. Ground points 6-9, in the main wiring harness
• 376-378. Ground points 11-13, in the main wiring harness
• 380-382. Ground points 15-17, in the main wiring harness
• 384. Ground point 19, in the main wiring harness
• 387. Ground point 22, in the main wiring harness
• 389. Ground point 24, in the main wiring harness
• 391. Ground point 26, in the main wiring harness
• 395-400. Ground points 30-35, in the main wiring harness
• 406/407. Ground point 3, in the driver/front passenger door wiring
• 431. Ground point 2, in the ceiling wiring
• 437. In the license plate light wiring
• 438. Ground point 3. in the ceiling wiring 456-458. Ground points 1-3, in the front bumper wiring
• 502. Threaded connection 1 (30a), on the relay holder
• 507. Threaded connection (30), on the fuse holder (on the battery) 514. Threaded connection 4 (30a), on the relay holder
• 610. Ground point for audio unit, under center console, front
• 612. In the center of the trunk lid
• 638/639. Right/left pillar A
• 645-647. Mass points 1-3, on the bulkhead
• 652. Ground point for engine and transmission
• 657. Mass point 1, left, near the rear window
• 671-673. Mass points 1-3 (in front on the left longitudinal beam)
• 675/676. Ground points 2, right/left in the trunk
• 683/684. Front on right/left longitudinal beam
• 685/686. Mass points 1/2 front on right longitudinal beam
• 687/688. Mass points 1/2, on the central tunnel 689. In the center of the roof, in front

Power connections

Note: The connections listed below without specifying their location are located in the main wiring harness.

• B154. Connection 1 (DCt), in the passenger compartment wiring
• B162. Connection 75a, in the passenger compartment wiring
• B231. Connection 5 (30a), in the passenger compartment wiring
• B250. In the ceiling wiring
• B275. Connection (87)
• B277. Connection 1 (15a)
• B280-B282. Connections 4-6 (15a)
• B284. Compound 8(15a)
• B287/B288. Connections 11/12 (15a)
• B316. Connection 2 (30a)
• B318-B320. Connections 4-6 (30a)
• B322/B327/B329. Connections 8/13/15 (30a)
• B331/B332/B334. Connections 17/18/20 (30a)
• B335. Compound 1 (54)
• B340/B341. Connections 1/2 (58d)
• B344. Compound 1 (61)
• B346. Compound 1 (75)
• B348/B349. Connections 1/2 (75A)
• B351-B353. Connections 2-4 (87a)
• B358-B360. Connections 9-11 (87a)
• B362. Compound 13 (87a)
• B364/B365. Connections 15/16 (87a)
• B367/B368. Connections 18/19 (87a)
• B369. Connection 1 (5 Volts)
• B379. Compound 1 (Brake wear indicator)
• B383/B384. Connections 1/2 (cAN bus transmission line, signal 1)
• B390/B391. Connections 1/2 (cAN bus transmission line, signal 0)
• B397/B4O6. Compounds 1 (cAN bus comfort devices, signal 1)
• B441. Connection (CCS)
• B444. Compound 1 (diagnostics)
• B465-B487. Connections 1-23
• B520. Connection (RL)
• B528. Connection 1 (LIN bus)
• B537-B539. Connections 28-30
• B549. Connection 2 (LIN bus)
• B552. Connection 2, in ceiling wiring
• B555. Connection 2(50)
• B559. Compound 1 (30g)
• B564-B573. Connections 31-40
• B574/B575. Connections 20/21 (87a)
• B577. Connection (LIN bus), in ceiling wiring
• B592/B593. Connections 1/2, in the Climatronic system wiring

Other connections

• D101/D106. 1/4 connections, in engine wiring
• D136. Power supply connection 2 (15a), in the engine compartment wiring
• D141. Connection (5V), in the engine wiring
• D174. Ground point 2 (5V), in engine wiring
• D180/D181. Connections 1/2 (87a), in the engine compartment wiring
• D190. Ground point 3 (5V), in engine wiring
• D52. Power supply connection (15A), in the engine compartment wiring
• E48. Connection (injectors), in the fuel injection system wiring
• M1. Power connection 1 (30), in seat adjustment wiring
• M9. Seat adjustment wiring connection
• M41-M44. Connections 1-4, in the driver's seat wiring
• M51-M54. Connections 1-4, in the front passenger seat wiring
• M61-M68. Connections 1-8, in the rear seat wiring
• M94-M96. Connections 2-4, in the seat adjustment wiring
• 04. Power connection (30as), in seat heating wiring
• 015/016. Connection 4, in seat heating wiring
• R75/R76. Connections (58d) 1/2, in the door control unit wiring
• U2. Connection 1 (15), in the automatic transmission wiring
• W41. Power supply connection (58), in the license plate light wiring
• X149/X150. Connection (5V/58), in the rear bumper wiring
• X151. Connection (5V), in the front bumper wiring
• X65. Connection (parking assistance system), in the front bumper wiring
• X68. Power connection (parking assistance system), in the rear bumper wiring

Switches, switches, regulators

• E1. Light switch
• E2. Direction indicator switch
• EZ. Emergency signal switch
• E4. Switch for low beam headlights and high beam signaling
• E7. Fog light switch
• E18. Rear fog light switch
• E20. Instrument and switch illumination regulator
• E22. Windscreen wiper interval switch
• E24. Driver's seat belt switch
• E25. Front passenger seat belt switch sensor
• E26. Sensor-switch for glove compartment illumination
• E34. Tailgate Window Wiper Switch
• EZZ. Windscreen wiper interval mode switch
• E40. Driver's door window lift control switch
• E43. Mirror adjustment switch
• E44. Headlamp Washer Pump Switch
• E45. Cruise control switch
• E48. Mirror selection switch for adjustment
• E52. Rear left window lift switch (in the door)
• E53. Rear left window lift switch (in the driver's door)
• E54. Rear right window lift switch (in the door)
• E55. Rear right window lift switch (in the driver's door)
• E74. Battery main/isolation switch
• E81. Front right window lift switch (in the driver's door)
• E94/95. Front left/right seat heating regulator
• E102. Headlight leveling regulator
• E107. Front passenger door window lift control switch
• E128/E129. Rear left/right seat heating control switch
• E139. Sunroof sliding cover control switch
• E177. Front passenger seat lumbar support adjuster
• E180. Windscreen heating switch
• E218-E220. Button for setting seat position #1-#3
• E224. Front passenger airbag switch
• E231. Switch for heated exterior mirrors
• E233/E234. Remote/manual trunk release button.
• E256. TCS/ESP systems switch
• E263. Switch for folding the outside rearview mirror
• E2bb. Parking assistance switch
• E267. Interior volume sensor switch
• E308/E309. Driver/front passenger interior locking switch
• E318. Child safety lock switch
• EZ19. Fuel tank filler flap release button
• E325. Sunroof Switch
• E326. Front interior light switch
• E335/E336. Switch for adjusting the lumbar support height/protrusion
• E337. Massage function switch
• E360. Vehicle tilt sensor switch
• E415. Vehicle access authorization and engine start switch
• E418. Switch for adjusting the seat position in the longitudinal direction
• E421. Tilt adjustment switch
• E424. Seat cushion height adjustment switch
• E425. Backrest adjustment switch
• E447. Seat position memory button
• E454/E455. Rear left/right reading light
• E457/E458. Driver/front passenger side reading light
• E492. Tire inflation pressure monitoring display key
• E538. Parking brake switch
• E540. "AUTO HOLD" function switch

Sensor switches, contact switches

• F. Brake light switch sensor
• F1. Engine oil pressure switch
• F2/3. Driver/front passenger door contact switch
• F4. Reverse light switch sensor
• F10/F11. Contact switch in rear left/right door
• F34. Low brake fluid level switch
• F47. Brake pedal position sensor switch (in the engine compartment)
• F59. Driver's door single lock switch
• F125. Multifunctional switch
• F138. Airbag coil contact spring
• F147/148. Driver/front passenger side vanity mirror lighting contact switch
• F189. Tiptronic mode switch sensor
• F220/221. Single locking unit in driver/front passenger door
• F222/223. Single locking unit in rear left/right door
• F256. Trunk lid locking unit
• F266. Bonnet contact switch
• F265. Cooling system thermostat with control from MAP sensor
• F319. Selector lever lock switch in position P

Sensors, control and measuring instruments

• G/G1. Fuel gauge/sensor
• G3. Coolant temperature gauge
• G5. Tachometer
• G6. Fuel distribution pump
• G17. Interior temperature sensor
• G21. Speedometer
• G28. Crankshaft speed sensor
• C-31. Boost air pressure sensor
• G32. Low coolant level sensor
• G33. Low washer fluid level sensor
• G34. Front left brake pad wear sensor
• G39. Lambda probe
• G40. Hall sensor
• G42. IAT sensor
• G44/G45. Right rear/front wheel sensor
• G46/G47. Left rear/front wheel sensor
• G59/60. Driver/front passenger seat temperature sensor
• G61. Knock Sensor #1
• G62. Coolant temperature sensor
• G65. High pressure sensor
• G66. Knock Sensor #2
• G70. MAF sensor
• G71. Intake manifold pressure sensor
• G79. Accelerator pedal position sensor
• G81. Fuel temperature sensor
• G83. Radiator outlet coolant temperature sensor
• G85. Steering wheel angle sensor
• G93. Transmission oil temperature sensor
• G94/G95. Rear left/right seat temperature sensor
• G107. Sunlight intensity sensor
• G108. Lambda probe #2
• G112/G113. Potentiometer of the electric motor of the drive of the central flap/air flow flap
• G128. Front passenger seat occupied sensor
• G13O. Post-catalytic lambda probe
• G131. Post-catalytic lambda probe #2
• G134. Sunlight Intensity Sensor #2
• G135. Potentiometer of the electric motor of the drive of the window blower flap
• G143. Potentiometer of the electric motor of the air recirculation flap drive
• G150/G151. Left/right ventilation system temperature sensor
• G179/180. Driver/front passenger side airbag activation sensor
• G182. Transmission Input Shaft Speed Sensor
• G185. Sensor No.2 of the accelerator pedal position
• G186. Throttle actuator (electronic power control)
• G187/188. Throttle position sensor 1/2
• G190. Frontal impact sensor
• G191/192. Temperature sensor (ventilation system) central/in footwell
• G195. Transmission output shaft speed sensor
• G203/G206 Rear left/right parking assistance sensor
• G212. EGR system potentiometer
• G219. Sensor for adjusting the position of the driver's seat backrest
• G220/G221. Potentiometer of the electric motor of the left/right temperature control flap drive
• G227. Sensor for adjusting the driver's seat in the longitudinal direction
• G232. Sensor for adjusting the driver's seat tilt
• G247. Fuel pressure sensor
• G252/G255. Front right/left parking assistance sensor
• G256/G257. Rear airbag activation sensor on driver/front passenger side
• G261/G262. Temperature sensor in the left/right footwell
• G263. Evaporator outlet flow temperature sensor
• G266. Engine oil level and temperature sensor
• G269. Steering torque sensor
• G273. Interior volume sensor
• G287. Post-catalytic lambda probe #3
• G294. Brake servo pressure sensor
• G299. IAT Sensor #2
• G303. Interior Volume Sensor Receiver/Sender Module #1
• G330. Potentiometer of the electric motor of the damper drive, diffused air supply
• G374/G375. Height/Length Stop Adjustment Sensor
• G384. Vehicle tilt sensor
• G397. Rain and light sensor
• G410. Low fuel pressure sensor
• G423. Potentiometer for adjusting the height of the lumbar support (models with massage function)
• G450. Exhaust Gas Pressure Sensor No.1
• G452. Front passenger seat belt emergency tensioner squib #2
• G453. Driver's side inflatable curtain igniter
• G476. Clutch pedal position sensor
• G483. Brake servo vacuum sensor
• G503. Sensor for seat height adjustment
• G506. Temperature sensor before diesel particulate filter
• G507. Temperature sensor before turbocharger
• G514/G515. Potentiometer for horizontal/vertical adjustment of left outside rearview mirror
• G516/G517. Potentiometer for horizontal/vertical adjustment, right outside rearview mirror
• G527. Temperature sensor behind the diesel particulate filter

Sound signals

• N. Klaxon
• H2. High-frequency horn
• I3. Buzzer or gong
• H7. Low-frequency horn
• H12. Anti-theft alarm siren
• H15/H22. Front/rear parking assistance buzzer

Electronic control units

• J. ECM
• J4. 2-tone horn
• J9. Rear window heating relay
• J47. Windscreen heating relay
• J49. Fuel pump relay #2
• J104. Used ABS
• J119. Multifunctional display
• J126. Used fresh air supply fan
• J1Z6. Used seat and steering column position adjustment (with memory function)
• J179. Used glow plugs
• J217. Used automatic transmission
• J234. Used SRS
• J245. Used adjustment of the upper hatch cover
• J255. Used Climatromc system
• J285. Used instrument cluster with display
• J293. Used radiator fan
• J301. Used air conditioning system 3317/3329. Terminal voltage supply relay 30/15
• J338. Throttle body
• J386/387. Used driver/front passenger doors
• J388/389. Used rear left/right door
• J393. Central control unit for comfort equipment
• J400. Used with windscreen wiper drive motor
• J466. S/U parking assistance system
• J500. Used EP AS
• J519. Used on-board network
• J527. Used steering column electronics
• J533. Data bus diagnostic connector
• J538. Used fuel pump
• J540. Used parking brake
• J623. ECM
• J682. Terminal 50 Power Supply Relay
• J706. Used front passenger seat occupancy detection
• J729/J730. Relay 1/2 double washer
• J764. Used electronic steering column lock
• J774/J786. Used heated front seats

Lighting fixtures

• K18. Trailer direction indicator lamp
• K28. Coolant temperature/level control pump
• K29. Glow plug indicator lamp
• K31. Cruise control indicator lamp
• K37. Low washer fluid level indicator lamp
• K38. Low engine oil level indicator lamp
• K47. ABS warning light
• K65/K94. Left/right direction indicator lamp
• K105. Fuel reserve indicator lamp
• K118. Brake system indicator lamp
• K132. Power Management Malfunction Indicator Lamp
• K133. Control lamp for full locking function of single lock
• K136. Parking assistance system indicator lamp
• K145. Front passenger airbag deactivation control pump
• K155. TCS/ESP systems control lamp
• K162. Control lamp for disabled interior volume sensor
• K170. Lighting fixture lamp malfunction indicator lamp
• K174/K175. Driver/front passenger interior locking indicator lamp
• K188. Vehicle tilt sensor indicator lamp
• K213. Parking brake indicator lamp
• K216. Control lamp No.2 of ESP and TCS systems
• K236. Electronic brake warning lamp
• K237/K238. AUTO HOLD function control lamp No.1/No. 2
• L9. Light switch illumination
• L22/23. Left/right fog lamp bulb
• L28/L32. Front/rear cigarette lighter illumination
• L4. Left rear fog light bulb
• L71. TCS switch illumination
• L76. Button illumination
• L78. Illumination of the position regulator of the outside mirrors
• L101. Selector lever position display illumination
• L117. Parking assistance switch illumination
• L118. Interior volume sensor switch illumination
• L120. Glove compartment lighting
• L131/L132. Turn signal lamp in outside left/right mirror
• M1/2. Left front/right rear side light bulb
• M3/4. Right front/left rear side light bulb
• M5/6. Left front/rear turn signal lamp
• M7/8. Right front/rear turn signal lamp
• M9/10. Left/right brake light bulb
• M17. Right reversing light bulb
• M25. High-level brake light bulb
• M29/30. Left low/high beam lamp
• M31/32. Right low/high beam lamp
• N110. Left door release handle illumination
• W1. Front interior light W3. Trunk light
• W6. Light in the glove box
• W9/W10. Light in left/right footwell
• W11/W12 Rear left/right reading light
• W14/W20. Vanity mirror light bulb, front passenger/driver side
• W31/W32. Front left/right sill light
• W33/W34. Rear left/right sill light
• W39/W40 Left/Right Central Reading Light
• W43. Rear interior light
• W52/W53. Front left/right sill light (in the outside rearview mirror)
• X. License plate light

Valves, electromagnetic valves, pyropatrons

• N18. EGR valve
• N30-33 Injectors for cylinders 1-4 respectively
• N70. Ignition coil #1 with output stage
• N75. Boost pressure control solenoid valve
• N79. PCV system heating element
• N80. E/m valve No.1 of the EVAP system canister
• N88-93. Solenoid valve 1-6 respectively
• N95. Driver's Airbag Spark Plug
• N127. Ignition coil #2 with output stage
• N131/N132. Squib No.1/No. 2 Airbag front passenger
• N153/N154. Driver/front passenger seat belt emergency tensioner squib No.1
• N153/N154. Driver/front passenger seat belt emergency tensioner squib #2
• N199/200. Driver/front passenger side airbag squib
• N₂01/202. Driver/front passenger side inflatable curtain igniter
• N₂05. Intake camshaft control valve
• N₂40-243. Solenoid valve of injector cylinder 1-4
• N₂50. Driver's Airbag Pyropatron No.2
• N₂51/252. Driver/front passenger side inflatable curtain igniter
• N₂76. Fuel pressure regulating valve
• N₂80. Air conditioning compressor regulating valve
• N₂82/N₂83. Solenoid valves No.9/10
• N₂91/292. Ignition coils 3/4 with output stage
• N316. Intake manifold flap valve
• N345. EGR cooler valve
• N360. Steering column lock control element
• N376. Ignition Switch Rotation Interlock Solenoid Valve

Electrical wiring connectors, sockets

• T1. Screw connection, on the distribution block in the engine compartment
• T2ba. 2-pin connector, black, behind the right headlight
• T4a. 4-pin connector, near the starter
• T4ba, T4db. 4-pin connector, black, under the front passenger seat
• T4bv. 4-pin connector, black, under the driver's seat
• T46a/T46b. 4-pin connector, black, under left/right side of rear seat
• T6af 6-pin connector, on the distribution block in the engine compartment
• T8a. 8-pin connector, black, on the left front longitudinal beam
• T8d. 8-pin connector, right on the rear bumper
• T8x/T8u. 8-pin connector near injectors/cylinder head
• T10c/T10d 8-pin connector under driver/front passenger seat
• T10m 10-pin connector, on the distribution block in the engine compartment
• T10o, T10w. 10-pin connector, on transmission
• T10x. 10-pin connector, near the selector lever
• T14f 14-pin connector, on transmission
• T16d 16-pin diagnostic connector
• T16ks/T16ls. 16-pin connector, front, left/right outside rearview mirror
• T20b. 20-pin connector, on the air conditioner control unit
• T20c. 20-pin connector, on the Climatromc system unit/air conditioning control unit
• T40. 40-pin connector, under the distribution block in the engine compartment
• U1. Cigarette lighter
• U5. 12V socket, in the trunk
• U9. Rear cigarette lighter
• U10. Trailer Wiring Connector
• U18. 12V socket #2, in the trunk

Electric motors, fans, pumps

• V. Windshield wiper motor
• VI. Electric motor for the drive of the sliding cover of the upper hatch
• V2. Fresh air supply fan
• V7. Radiator fan
• V12. Electric motor for rear window wiper
• V17/V25. Left/right outside rearview mirror drive motor
• V26/27. Electric motor for rear left/right window lift
• V28/V31. Electric motor for driver/front passenger seat adjustment in longitudinal direction
• V45/V46. Driver/front passenger seat backrest adjustment electric motor
• V48/49. Left/right headlight leveling motor
• V56/V57. Driver/front passenger door lock drive motor
• V59. Windscreen and rear window washer pump
• V70. Electric motor for the central flap drive
• V71. Electric motor for air flow control flap drive
• V107. Electric motor for windshield defroster flap drive
• V121/V122. Left/right outside rearview mirror folding motor
• V126/V130. Electric motor for adjusting the lumbar support of the front passenger seat in the vertical/longitudinal direction
• V138. Driver's seat height adjustment electric motor
• V147/148. Electric motor front left/right window lifter
• V149/150. Electric motor for adjusting left/right outside rearview mirror
• V154. Air recirculation flap drive electric motor
• V155. Fuel filler flap release motor
• V157. Electric motor for flap drive in intake manifold
• V158/V159. Electric motor for left/right temperature control flap drive
• V161/V162. Electric motor for additional locking of the single door lock of the driver/front passenger
• V163/V164. Electric motor for additional locking of single rear left/right door lock
• V187. Power steering motor
• V213. Electric motor for the diffuse air supply flap drive
• V214/V215. Rear left/right door single lock motor
• V229/V230. Electric motor for adjusting the driver's seat lumbar support in the vertical/longitudinal direction
• V243/V244. Driver/front passenger seat tilt adjustment motor
• V246. Electric motor for adjusting the height of the front passenger seat
• V254. Electric motor for releasing the luggage compartment lid
• V282/V283. Left/right parking brake motor
• V328. Massage function pump

Mirrors and displays

• Y6. Automatic transmission mode selector lever position indicator
• Y7. Automatic dimming interior rearview mirror
• Y20/Y21 Left/right outside rearview mirror with automatic dimming

Heating elements

• Z1. Heated rear door glass
• Z2. Heated windshield
• Z4/5. Heated outside left/right mirror
• Z6/7. Driver's seat cushion/backrest with heating
• Z8/9. Heated front passenger seat cushion/backrest
• Z10/11 Rear left seat cushion/backrest
• Z12/13. Rear right seat cushion/backrest
• Z19. Lambda probe heating
• Z28. Lambda probe heating #2
• Z29. Post-catalytic lambda probe #1 heating
• Z30/Z64. Post-catalytic lambda probe heating #2/#3
• Z76/Z77. Driver's seat cushion left/right side support heating
• Z73/Z79. Left/right side support heating for driver's seat back
• Z80/Z81. Front passenger seat cushion left/right side support heating
• Z84/Z85. Heated left/right side support of rear right seat cushion
• Z86/Z87. Heated left/right side support of the rear right seat back.
• Z83/Z89. Left/right rear seat cushion side support heating
• Z90/Z91. Left/right rear seat backrest side support heating

(The original article is available on the website: AUDImanual)