The 1.8T Wiring Harness Explained

[AudiA4_20T]

Hey guys, thought I’d document this for people always trying to figure this stuff out. This should also help for my 2.7T swap. This is for a 2002 harness and I am missing a few connectors like SAI and MAF.





MAP Sensor
Connector: Black (4 pin)
1: Black
2: Empty
3: White with black stripe
4: Grey with blue stripe

Oil Level
Connector: Black (3 pin)
1: Black with red stripe
2: Brown
3: Red with green stripe

Thermostat (possibly wrong)
Connector: Black (2 pin)
1: Brown
2: Blue with brown stripe

Lower Coolant Temp Sensor
Connector: Black (2 pin)
1: Yellow with black stripe
2: Blue with black stripe

Throttle Body
Connector: Black (6 pin)
1: Purple with red stripe
2: Green with purple stripe
3: Red with purple stripe
4: Purple with red stripe
5: Brown with purple stripe
6: Grey with brown stripe

A/C Compressor (possibly wrong)
Connector: Black (2 pin)
1: Blue
2: Blue

IAT
Connector: Black (2 pin)
1: Black with red stripe
2: Black

Alternator (possibly wrong)
Connector: Black (2 pin)
1: Green with blue stripe
2: White with green stripe

N112
Connector: Brown (2 pin)
1: Green with yellow stripe
2: Brown with black stripe

N249
Connector: Black (2 pin)
1: Green with yellow stripe
2: Yellow with green stripe

Wideband 02
Connector: Black (6 pin)
1: White
2: Black with white stripe
3: Green with yellow stripe
4: Red with white stripe
5: Brown
6: Grey with green stripe

Rear 02 Sensor
Connector: Brown (4 pin)
1: Green with yellow stripe
2: White with grey stripe
3: Purple
4: Red

Crank Position
Connector: Grey (3 pin)
1: Black
2: Blue
3: Grey

Knock Sensor (Rear)
Connector: Blue (3 pin)
1: Yellow
2: Green
3: Black

Knock Sensor (Front)
Connector: Green (3 pin)
1: White
2: Brown
3: Black

???
Connector: Black (3 pin)
1: Blue with yellow stripe
2: Empty
3: Brown with yellow stripe

Oil Pressure
Connector: Black (1 pin)
1: Yellow

Speed Sensor (Trans)
Connector: Black (3 pin)
1: Empty
2: Brown
3: Brown with red stripe

Other Trans Sensor (??)
Connector: Black (5 pin)
1: Empty
2: Blue with red stripe
3: Black with blue stripe
4: Empty
5: Empty

????
Connector: Black (1 pin)
1: Red with black stripe

VVT Tensioner
Connector: Black (2 pin)
1: Green with blue stripe
2: Yellow with grey stripe

Coolant Temp (Top)
Connector: Black (4 pin)
1: Blue with brown stripe
2: Brown with yellow stripe
3: Black
4: Brown with grey stripe

Cam Position Sensor
Connector: Black (3 pin)
1: White with black stripe
2: Green with grey stripe
3: Black

Injector 1 (Front)
Connector: Black (2 pin)
1: Red with blue stripe
2: Black with green stripe

Injector 2
Connector: Black (2 pin)
1: Red with blue stripe
2: Brown with blue stripe

Injector 3
Connector: Black (2 pin)
1: Red with blue stripe
2: Grey with green stripe

Injector 4
Connector: Black (2 pin)
1: Red with blue stripe
2: Grey with purple stripe

N75
Connector: Black (2 pin)
1: Black with purple stripe
2: Yellow with white stripe

EVAP
Connector: Black (2 pin)
1: Green with yellow stripe
2: Purple

Coilpack 4 (Rear)
Connector: Black (4 pin)
1: Red with green stripe
2: Brown
3: Brown with black stripe
4: Brown with yellow stripe

Coilpack 3
Connector: Black (4 pin)
1: Red with green stripe
2: Brown
3: Grey with black stripe
4: Brown with yellow stripe

Coilpack 2
Connector: Black (4 pin)
1: Red with green stripe
2: Brown
3: Grey with brown
4: Brown with yellow stripe

Coilpack 1 (Front)
Connector: Black (4 pin)
1: Red with green stripe
2: Brown
3: Grey
4: Brown with yellow stripe

Coilpack Grounds: Brown with yellow stripe

************************************************** **************************************



2000 Audi S4 Body Harness Plugs:

- T10, Brown, 10 pin
1. green/red - K-line diag wire into ECU pin 43
2. green/brown - to pin 47 on ECU from ?
3. white/blue - vehicle speed signal to pin 54 on ECU
4. red/black - from park/neutral position relay to ignition/starter switch
5. black/blue - to pin 3 on back-up light switch
6. unused
7. unused
8. black/red - to pin 1 on oil level thermal sensor
9. red/grey - to pin 3 on oil level thermal sensor
10. yellow - to pin 81 on ECU from ?

- T10m, Black, 10 pin
1. blue - goes to the voltage regulator (D+/61)/generator
2. green/blue - rpm signal to pin 37 on ECU
3. white/grey - from cluster to oil pressure switch
4. red - from positive wire 30 to ECU pin 62
5. brown/yellow, pin 3 on engine coolant temp sensor
6. unused
7. blue/green - from cluster to pin 1 on Engine Coolant Level Warning Switch
8. red/blue - power pin 15 to fuel pump relay and then ECU
9. blue/brown - from cluster to ground connection 2?
10. brown/red - from cluster to to pin 2 on speedometer vehicle speed sensor (VSS)

- T10ar, Orange, 10 pin
1. red/green - from 20A fuse in fuse holder to power output stage pin 1 connector T5d
2. red/brown - to pin 48 on ECU from ?
3.
4. unused
5. black/blue - pin 1 on injector 1 to 20amp fuse in fuse holder
6. white/yellow - to pin 1 on leak detection pump
7. yellow/red - to pin 2 on leak detection pump
8. green/yellow - to 15A fuse in fuse holder
9.
10. blue/lilac - engine overhead warning light

- T15m, Red, 15 pin
1. green/brown - From ABS control module to ECU pin 74
2. unused (only for FWD)
3. black/green - A/C control head to ECU pin 41
4.
5. black/lilac - to pin 30 on ECU from ?
6.
7.
8.
9.
10.
11.
12.
13.
14. orange/brown - connection (low-bus)
15. orange/black - connection (high-bus)

- T15, White, 15 pin
1. yellow/blue - to pin 1 (4 on 2001) on throttle body
2. yellow/lilac - to pin 2 on throttle body
3. brown/red - to pin 3 on throttle body
4. green/yellow - to pin 4 (5 on 2001) on throttle body
5. green - to pin 5 (1 on 2001) on throttle body
6. brown/green - to pin 6 on throttle body
7. red/grey - to pin 1 on connector T6y
8. blue - to pin 2 on connector T6y
9. red/yellow - to pin 3 on connector T6y
10. black/white - to pin 6 on connector T6y
11. red/black - to pin 2 on brake light switch
12. white/red - to pin 4 on brake light switch
13. red/green - to pin 1 on clutch vacuum vent valve switch
14.
15.

************************************************** ********************************



2003 B6 A4 1.8T harness

T10, Black, 10 pin
1. blue - generator
2. unused
3. white/grey - Oil pressure switch
4. unused
5. red/green - from pin 121 on ECU to ?
6. brown/yellow - pin 3 from engine coolant level warning light
7. blue/yellow - Engine coolant level warning switch
8. unused
9. blue/brown - Engine coolant temp sensor
10. brown/red - Speedometer vehicle speed sensor pin 2 (unused in 03)

T10a, Brown, 10 pin
1. red/blue - from injector harness to... ?
2. black/red - Oil level thermal sensor pin 1
3. unused
4. red/black - Ignition/starter switch to ground
5. black/blue - Back up light switch pin 3
6. green/red - control module with indicator unit in instrument panel insert
7. unused
8. green/yellow - connector for fuse 234, connects MAF, N112, N80, N249
9. red/grey - Oil level thermal sensor pin 3 (red/green for 03)
10. unused

T17e, White, 17 pin
1. brown/green - to pin 1 on throttle body
2. yellow/lilac - to pin 2 on throttle body
3. brown/red - to pin 3 on throttle body
4. yellow/blue - to pin 4 on throttle body
5. grey/yellow - to pin 5 on Throttle Body
6. brown - to pin 6 on throttle body
7. unused
8. unused
9. unused
10. blue/green - from pin 38 ECU to steering column electronics module
11. red/black - to pin 4 on brake light switch from ECU
12. white/red - to pin 2 on brake light switch from ECU
13. red/green - to pin 2 clutch vacuum vent valve switch
14. grey/white - from pin 1 on locking relay for starter (clutch pedal switch) to pin 2 on clutch vent vacuum valve switch
15. black/lilac - from ? to ECU
16. red/grey - from power supply relay to fuse S229 (20A)
17. unused

T17d, Red, 17 pin
1. white/yellow - pin 1 leak detection pump to ECU
2. grey/red - pin 2 leak detection pump to ECU
3. unused
4. unused
5. blue/brown - ? (03)
6. lilac/blue - to airbag control module from pin 67 ECU
7. unused
8. unused
9. unused
10. red/blue - to pin 5 on fuel pump relay
11. red/white - to ECU pin 24 to coolant fan control module
12. unused
13. orange/brown - Wire connection (low-bus)
14. orange/black - Wire connection (high-bus)
15. blue/red - reverse lamp connector
16. unused
17. unused

************************************************** ************************************************

2004 B6 S4 4.2 harness

T10, Black, 10 pin
1. blue – generator ???
2.
3. white/green – from instrument panel to F1 (oil pressure switch)
4.
5.
6. brown/yellow – from pin 3 on F66 (Engine Coolant Level Warning Switch) to ground 269
7. blue/yellow – from J285 (dash) to pin 1 on F66 (Engine Coolant Level Warning Switch)
8.
9. blue/brown – from J285 (dash) to pin 1 on G2 (Engine Coolant Temperature Sensor)
10.

T10a, Brown, 10 pin
1. red/blue – from 25 to D95 ground for injector 1-6 ???
2. black/red – from 21 to pin 1 on G266 (Oil Level Thermal Sensor) ???
3.
4. red/black - to the 50 pin on the starter
5. black/blue – from connector A70 to F4 (Back-up light switch)
6. for auto cars
7.
8. green/yellow – from 26 to D22 ground
9. red/green – from instrument panel to pin 3 on G266 (Oil Level Thermal Sensor)
10.

T17e, White, 17 pin
1. brown/green – from throttle body pin 1 to ECU pin 72
2. yellow/lilac - from throttle body pin 2 to ECU pin 73
3. brown/red - from throttle body pin 3 to ECU pin 36
4. yellow/blue - from throttle body pin 4 to ECU pin 35
5. green/yellow - from throttle body pin 5 to ECU pin 33
6. brown - from throttle body pin 6 to ECU pin 34
7.
8.
9.
10. blue/green – from dash to ECU
11. red/black – pin 4 on brake light switch to ECU pin 56
12. white/red – pin 2 on brake light switch to ECU pin 55
13. green/grey – pin 2 on clutch vacuum vent valve switch to ECU pin 39
14.
15. black/lilac – from 20 to pin 21 on ECU
16. red/grey – from ECM power supply relay to fuse 229 (20A) to 229???
17.

T17d, Red, 17 pin
1. yellow - from pin 1 on leak detection pump to ECU pin 80
2. green/red – from pin 2 on leak detection pump to ECU pin 25
3. red/yellow – from coolant fan control module 2 to ECU pin 104
4.
5.
6. lilac/blue (possibly not there) – from fuse 234 to ECU pin 61???
7. green/black – from pin 1 on N220 valve for exhaust flap to ECU pin 22
8.
9.
10. red/blue – pin 4 on fuel pump relay to pin 65 on ECU
11. red/white – from coolant fan control module 1 to ECU pin 66
12.
13. orange/brown – CanBus (low) from instrument panel to pin 58 on ECU
14. orange/black – CanBus (high) from instrument panel to pin 60 on ECU
15. blue/red – from J393 (Central Control Module for Comfort System) to 220???
16.
17.

[Staz]

i hate that youre missing the maf one !!!!!!!!!!!!!!!

nice writeup though

[AudiA4_20T]

lol someone will fill it in.

[a4darkness]

I can't even. This. Seriously. Wow. Just wow.

Really great idea.

[alexza4]

real nice Clint! virtual rep to you man.

[AudiA4_20T]

It's getting better when I trace every wire around the harness down to the pin

[Dolphin18T]

You know the Bentley manual has all of this, right?

Let me know if you need any diagrams and I'll post them up.

[alexza4]

are you doin this shit now? you must be bored ;)

how are you doin with those PSS9's? still want them!

[AudiA4_20T]

You know the Bentley manual has all of this, right?

Let me know if you need any diagrams and I'll post them up.

I've seen the bentley though and it's rather confusing. I gotta find my disc I know its somewhere. YGPM

[Dolphin18T]

Here's an example of what's in the manual. You have to practice using the guide it has leading in to the wiring diagram section to be able to read it easily, but it's worth it. My trans swap would have been a nightmare without it, or I probably would have just bypassed the starter interlock relay, which I really didn't want to do.

[Bische]

great idea!

[dougyfresh]

I've seen the bentley though and it's rather confusing. I gotta find my disc I know its somewhere. YGPM

It's not that confusing. Took me five minutes to read the diagram and figure out the clutch switch. It took Jake... well. it didn't as he couldt figure it out even after I laid out the steps and such.

Go to Raritan Valley and take a quick electronics course in reading diagrams.

The key information not posted yet are the pin outs for the ECU. again... in the bentley.

[texasboy21]

Anyone know how much a new harness is?

[AudiA4_20T]

Here's an example of what's in the manual. You have to practice using the guide it has leading in to the wiring diagram section to be able to read it easily, but it's worth it. My trans swap would have been a nightmare without it, or I probably would have just bypassed the starter interlock relay, which I really didn't want to do.

none of that makes sense to me lol

[Dolphin18T]

It's not that confusing. Took me five minutes to read the diagram and figure out the clutch switch. It took Jake... well. it didn't as he couldt figure it out even after I laid out the steps and such.

Go to Raritan Valley and take a quick electronics course in reading diagrams.

The key information not posted yet are the pin outs for the ECU. again... in the bentley.

Did you finally get both of Vince's clutch switches wired correctly? I thought you just jumped the relay.

It would take me quite a long time to to post up the images required to pinout the entire ECU... Hah.

[Staz]

could u possibly post up the diagram of the maf ? please !

[AudiA4_20T]

could u possibly post up the diagram of the maf ? please !

someone can yank the plug. I know its a 4 pin but idk the colors. My MAF wires are gone so idk lol

[Staz]

someone can yank the plug. I know its a 4 pin but idk the colors. My MAF wires are gone so idk lol

i meant to quote dolphin18t.. i know its the 4 pin i just changed out my connector along with splicing and adding a few wires that i bought from the dealer but its still giving me low voltage on the maf (so im thinking somethings wrong with the wiring somewhere down the line of it) .. was wondering is i buy a used harness and take the maf harness from it, if i could just run it behind the engine as the other wires do and if it plus directly/ near the ecu ?

[AudiA4_20T]

i meant to quote dolphin18t.. i know its the 4 pin i just changed out my connector along with splicing and adding a few wires that i bought from the dealer but its still giving me low voltage on the maf (so im thinking somethings wrong with the wiring somewhere down the line of it) .. was wondering is i buy a used harness and take the maf harness from it, if i could just run it behind the engine as the other wires do and if it plus directly/ near the ecu ?

yes you could pin one in but it'd be a nightmare. It was giving you low voltage so you replaced the whole MAF harness?

[Staz]

yes you could pin one in but it'd be a nightmare. It was giving you low voltage so you replaced the whole MAF harness?

heres the thread i posted on it

the techs at the dealer said it was my connecter having issues thats why my maf would keep blowing. so i wanted to order a whole harness for the maf but they said they didnt sell them. said id have to buy 4 wires and a new connector, splice the old ones, solder the new ones in and it would solve the problem. i did research and research and couldnt find a solution for it so i ended up doing what the dealer said and bought the stuff. replaced it, and was still giving me random low voltage.

so now im thinking im i just buy a used engine harness and take the maf harness out of it and run it behind where all the other wires are. Then just heat wrap them all since id have to take the oem wrap off to get the old maf harness out

heres what it looked like after i installed it

[A4SoftWalker]

Good info here. Nice to see it all laid out.

So that whole mass plugs into the ECU/ECM.... +ve rep

[AudiA4_20T]

adding more about the B5 S4 harness connectors

[AudiA4_20T]

stuff added at the bottom of the first post

[IVRINGS]

I hope you enjoy that package I sent you the other day. They said it should be there by Monday like I said. I'm going to finish up my timing stuff and pick a clutch this week and get things ready for wiring. I miss driving my car.

[AudiA4_20T]

started adding 2002 B6 wiring to it

[lookaught]

Nice Clint! Thanks!

I too find the Bentley manual annoying to read, particularly because the colors are written in German abbreviations on the diagrams which is a tad confusing (and I even speak german!).

[AudiA4_20T]

I started getting better at it but i have an actual harness coming too which should help

[diagnosticator]

Thanks for your efforts posting this valuable reference! I recommend you add this to the AZ Wiki. Included in the AZ Wiki, anyone can add to the content of this reference, a lot easier than as a single post/thread.

[diagnosticator]

The main features to understand to read the wiring diagrams, is that the top of the diagram is the +BAT, "30", and the bottom is Chassis Ground, "31". The current flows in the diagram from the top "+BAT, 30" to the bottom, "31, Chassis Ground". The numbers in the square boxes at the circuit traces, refer to the numbers along the bottom of the diagram, and indicate where the circuit trace continues in the diagram. Where a circuit trace continues, a box with the origination reference number corresponds to the destination reference number for that circuit.

[AudiA4_20T]

John I'm not done yet but this will be part of the 2.7T swap DIY

[IVRINGS]

I started getting better at it but i have an actual harness coming too which should help

Your welcome... I hope that I'm the next one to have mine up and running. I just wished my 6-speed swap would have been done a long time ago. Looks like 5-speed for now and maybe do FT's or K04's during the 6-speed so I can get out of the FORD

[AudiA4_20T]

well that's all I can get for now until I figure this thing out better.

[nefkntym]

Good info Clint, I am looking for pin out info for the 1.8t harness.

[AudiA4_20T]

Good info Clint, I am looking for pin out info for the 1.8t harness.

PM me with what you need I've been working on the side with it for awhile

[daghstdrummer]

WOW! sticky....

[Haenszel20v]

www.bentleypublishers.com

[Scubasteeve]

That's cool.

[AudiA4_20T]

www.bentleypublishers.com

Yea that's what I've been using. It makes sense after awhile but some of them are still very confusing

[SpeedWorksAuto]

Borrowed some info and reposted it here: http://www.audizine.com/forum/showth...42#post7054042

[CrazyCal]

Excellent write-up. Definite STICKY??????