B5 2.7T to B6 A4 Wiring guide

[Julian Aksnes]

The kick panel is under the dash against the left wall behind a piece of trim, its so the ecu gets the brake signal mostly used for the cruise control and being a b7 youll have to get the crash signal at either the ccm or the airbag module I would suggest the ccm itd easier to get at and I wouldn't touch the airbag module unless needed

But this T3au connector.. is it located behind the instrument cluster? So what it does is basicly just to jump the crash sensor since it doesnt come from the engine but from the car itself.. From behind the instrument cluster to the CCM or T17 brown that is

[Julian Aksnes]

Im unable to figure out my brake light problem. Its constant ON. Then I thought of something.. is it because I havent swapped the ABS yet? I can see from the wiring diagram that brake lights are on of the pins to rewire on the ABS.. any thoughts?

[blitz2190]

But this T3au connector.. is it located behind the instrument cluster? So what it does is basicly just to jump the crash sensor since it doesnt come from the engine but from the car itself.. From behind the instrument cluster to the CCM or T17 brown that is

Im unable to figure out my brake light problem. Its constant ON. Then I thought of something.. is it because I havent swapped the ABS yet? I can see from the wiring diagram that brake lights are on of the pins to rewire on the ABS.. any thoughts?

Didn't see this question the other day, no the t3au plug is connected(lookes like it is part of the plug) to the red plug in the ecu box. as for the crash signal you will need to get it at the ccm or airbag module, the brake light you may need to get at the kick panel if your not swapping the abs. I don't know right now off hand but I have said it before in a few threads which pin, and I think it is in the first post but don't have time to look today.

[Nayte]

Hi all, I'm new to the forums, but I've been reading through a lot of Audizine threads through the years.

I'm planning a 2.7 swap for my B7, but I am a looooooong way from doing any wiring. I am still in the research/parts gathering phase, and recently delved into the wiring & adaption threads.
I purchased a B6 3.0 MT parts car that I have been using to source the manual swap components, and I also have a 2.7 BEL motor with the matching ECU & harness.

In regards to the ABS, if I'm reading this right, can I swap over the ABS module from the 3.0 into my B7? Fortunately, my roommate has a B5 S4 (APB). I was able to compare the B5/6/7 modules, and they all appear to be different.

I already have the module pulled from the B6, and I'm going to pull the cluster as well. If I can use the module, do you know if it'll need the associated harness from the B6? Or should I re-wire it to the B7 harness? I've traced the harness back to the driver's side door in the B6, but I haven't had the chance to see how/if it's possible to remove from the chassis. I'd like to get as much out of the car as I can before it goes to the yard. Hopefully soon, because I need the space in my garage

[blitz2190]

you'll also need the yaw rate sensor behind the radio headunit from the 3.0 to match the abs, but you may not have to swap the abs if the bel computer can communicate with it. I don't think anyone has tested this yet, I would get the parts since they won't cost you anything then swap if you need to after doing the 2.7 swap. You will need the 3.0 abs plug as well I recommend cutting as much wire as you can to give yourself room to work when re wiring it. Everything you need to do is mentioned in the first post.

[Nayte]

I'll be sure to grab the yaw sensor as well. From what I could find, most threads only discussed APB swaps in depth, so I guess I'll see how the BEL differs. My garage isn't insulated (not fun in MI), so I planned on spending the winter studying wiring diagrams and comparing notes to what you have already put together.

I have the entire engine & harness pulled already (interior is also gutted) so I think I just need what I can get of the chassis harness, the cluster, and the yaw sensor.

Anyway, thanks for the write-up. I'll be sure to report back if I find anything in regards to the BEL.

[ADCS]

BEL is entirely different in terms of wiring, tuning and IMMO. The wiring is not any harder or easier (actually maybe easier since all OEM relays work). It just has a different pinout.

[mauromj]

So if I apply power (+12v) to T17d RED Pin10 red/blue (B6 chassis), this should power the fuel pump. Can anyone confirm this?

[blitz2190]

So if I apply power (+12v) to T17d RED Pin10 red/blue (B6 chassis), this should power the fuel pump. Can anyone confirm this?

right pin but it should be ground not 12v, the 12v comes from the ignition, the ground is triggered by the ecu.

[mauromj]

right pin but it should be ground not 12v, the 12v comes from the ignition, the ground is triggered by the ecu.

Ok.

And the 12v ignition source is external to the body plugs and Ecu, correct? Meaning I don’t have to wire anything special up for that?


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[blitz2190]

Correct it's already tied to the same post 30 that the wire with the nut attaches

[mauromj]

Cool. I just jumped it to ground and got it working.

I like to verify everything before I wire it up.

Whats everyone doing for a fan controller? I really dont like the idea of a relay triggering on and off based off the temp sensor. I would much rather have a PWM controller like the B5. Has anyone successfully set one of those up? I am having a hard time finding any info on the pinout.

I could always go with one of these (have one on my M3 track car), but I would rather have an OEM-ish solution.

http://www.autocoolguy.com/

[ADCS]

Many are using the B5 S4/C5 A6 fan control module.

[blitz2190]

Cool. I just jumped it to ground and got it working.

I like to verify everything before I wire it up.

Whats everyone doing for a fan controller? I really dont like the idea of a relay triggering on and off based off the temp sensor. I would much rather have a PWM controller like the B5. Has anyone successfully set one of those up? I am having a hard time finding any info on the pinout.

I could always go with one of these (have one on my M3 track car), but I would rather have an OEM-ish solution.

http://www.autocoolguy.com/

Why? Car fans have been controlled that way for a long time with no issue. The fan controller modules not so much they commonly go out. In either case be careful about which you use as it could run hot in some areas with the stock temp sensor as it's ment to supplement the viscous fan not replace it. But depends on how hot it gets by you. I personally went the relay route with a BMW switch and had been running just fine for almost 2 years of use so far.

[B6_A4_Kid]

What are you guys doing to trigger your fuel pump? Car cranks, injectors click, there’s spark, now we just need fuel.


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[Bob Marley]

What are you guys doing to trigger your fuel pump? Car cranks, injectors click, there’s spark, now we just need fuel.


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Stock fuel pump wiring circuit not working for you?

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[AudiA4_20T]

What are you guys doing to trigger your fuel pump? Car cranks, injectors click, there’s spark, now we just need fuel.


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Your crank position sensor is dead.

[B6_A4_Kid]

Stock fuel pump wiring circuit not working for you?

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Yeah, not sure why it’s not though.

The crank sensor was just replaced with a new OEM unit.


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[Bob Marley]

Yeah, not sure why it’s not though.

The crank sensor was just replaced with a new OEM unit.


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You need to comfirm that pump is getting powrr or not... what checks have you made so far?

This is basic but...

Obviously check fuse first...

Put a meter across the 4 pin connector leading to your fuel pump Hat ... Back Probe the 2 heavier gauge wires ...(the other two are for Fuel level float.)
I forget the colors...you should be getting +12v across those 2 when cranking.

If you're getting power disconnect the feed from the fuel rail and stick it in a bottle...when you crank fuel should come out & fill the bottle... if it doesnt...start working backwards towards the pump...pull the line feeding fuel filter check for flow... pull the line leaving Tank hat...etc.

If all that checks out...start looking elswhere, fuel system is good for the most part



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[B6_A4_Kid]

Ok I’ll check those this weekend. Would this have anything to do with us not having an m box ecu?


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[Bob Marley]

Ok I’ll check those this weekend. Would this have anything to do with us not having an m box ecu?


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Doubt that

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[mauromj]

Short the pin discussed earlier between blitz and I to ground (the body plug pin). This should power your fuel pump with the ignition on.

If you get nothing, troubleshoot your relay/fuse.

If yuo hear the pump running, you know the issue is with your ECU making up that connection. Likely due to the CPS.

[ADCS]

Yeah, not sure why it’s not though.

The crank sensor was just replaced with a new OEM unit.


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In my case, my crank sensor was good. The wiring on the engine harness was crap. 3 of the 4 wires were severed under the rubber boot. Fixed that and it fired right up.

[B6_A4_Kid]

I had a minute after work today and I busted out the power probe. I have power and ground at the connect, unfortunately when I removed the connector the whole thing just crumble, which is just awesome. Anyways, I don’t hear anything when I turn the key, no prime or anything, but power is getting to the pump.


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[AudiA4_20T]

The ECU is actually a gate for the fuel pump relay. Since the injectors & ECU are on the same power wire, you can rule that out. CPS is usually the reason the ECU doesn't ground the FP relay. CEL is on when the key is on ACC right?

[B6_A4_Kid]

There is no cel when key is on


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[blitz2190]

Hmm that could mean the ecu is not getting power, does the cell ever light up?

[B6_A4_Kid]

Nope. Never lights up, but car cranks and I feel like I can hear injectors popping.


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[B6_A4_Kid]

Anyone want to help me out with this? I am not sure what’s needed to power the ecu


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[blitz2190]

Without seeing the wires I would say go over it and recheck the harness, all you need to communicate with the ecu is the power wires on the first post and k-line. Obviously it won't work with just that but that's where I would start checking.

[AudiA4_20T]

Pin 4 needs constant 12V and black/blue wire needs switched 12V

[B6_A4_Kid]

Thanks for the help guys. We got it sorted out!


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[B6_A4_Kid]

Well my dudes, the time has finally come.

https://youtu.be/rU6vZaSyP54


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[B6_A4_Kid]

I just want to thank everyone who helped us along the way. Blitz and Clint, you guys are awesome! Huge thanks to you guys!


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[jjvwg]

blitz, looking at the wiring connections on the first post you show the following:


looking at the wiring diagrams, this completely cuts out the starter interlock relay and the need to depress the clutch to start the car. did you mean to do that?

[blitz2190]

I did, but i have a diagram I have meaning to upload to fix that for those that wish to retain it.

[jjvwg]

I did, but i have a diagram I have meaning to upload to fix that for those that wish to retain it.

10-4. im going to have a look at it also as I want to retain it so I will post it up if I get to it before you do.

[Andyb6biturbo]

Subscribed :)

[Krzysiekvtec]

How to avoid this?
Close fuel cap tank

[Krzysiekvtec]