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[aacordon]

So after much searching to figure out how to keep my stock bluetooth mic, and adapt the usb and aux cables to my Avic z120bt, there was nothing for the 2011. So i ripped my stock HU apart to find the pin-outs. Here they are...

the pinouts i wrote are for the stereo side, mirror it for the harness

USB (Male Connector looking at the back of the stereo)



____
|1 2|
|3 4|
-----

1. VBUS
2. GND
3. DATA -
4. DATA +



AUX Connector (Male Connector looking at the back of the stereo)



________ ___ _______
| |_| |_| |
|1 2 3 4 5 6 7 8 |
|9 10 11 12 13 14 15 16 |
______________________

1. N.C.
2. MIC SHIELD
3. SUBW+
4. SUB CONT (continous?)
5. AUX R+
6. AUX L+
7. MICDET (NOT SURE WHAT ITS FOR)
8. MIC IN
9. N.C.
10. N.C
11. SUBW-
12. SUBW SHIELD
13. AUX ON
14. AUX-LR-
15. MICDET
16. MICGND

The 20 Pin is still the same for the speakers, can, etc. connectors follow link below.Subaru 20-pin radio harness pin-out

hope this helps, please correct any errors i may have

[SVXdc]

Brilliant!

You've [started us down the road to a solution for] the current hot question -- 'how to retain the OEM mic with an aftermarket HU'. You've also confirmed my suspicion that the premium HU has a line-level subwoofer output (similar to the Navi HU and HUs in some recent Forester models).

ADDED: The sub output may be working in some Foresters. I think the needed components are unpopulated in Impreza HUs.

BTW, this thread is about the Subaru OEM HU, made by Clarion, with built-in USB and Bluetooth, but just a simple display. Picture:

This is not the Pioneer AVIC-U310BT that some Canadian models get.

First, let's change the pin numbers to match Subaru's wiring diagrams...

Aux/Mic/Sub socket

Subaru's pin numbering
(viewing rear of OEM HU or wires side of car's harness):
 _   ________________   _
| ---                --- |
| 8  7  6  5  4  3  2  1 |
|16 15 14 13 12 11 10  9 |
 ------------------------

Corresponding numbering on PC board:
  2  4  6  8 10 12 14 16
  1  3  5  7  9 11 13 15

PCB   Subaru   Description                  OEM Color
---   ------   --------------------------   ------------
16       1     Mic In (+)                   White/Black
14       2     Mic B+ (+5V supply)          Gray
12       3     Aux In Left +                Yellow
10       4     Aux In Right +               Blue
 8       5     Subwoofer Amp Turn-On        -
 6       6     Subwoofer Out + (positive)   -
 4       7     Mic Shield                   -
 2       8     NC                           -

15       9     Mic In Ground (-)            Violet/Red
13      10     Mic Detect                   Black/Blue
11      11     Aux Audio Ground             Shield
 9      12     Aux Enable                   Black/Orange
 7      13     Subwoofer Shield             -
 5      14     Subwoofer Out - (inverted)   -
 3      15     NC                           -
 1      16     NC                           -

Most people shouldn't worry about the PC board pin numbers. I've included them here for people who want to match them up to aacordon's picture.

Aux Input

The aux input is electrically the same as in previous years. When you plug something into the car's jack, the jack connects the Aux Enable pin to chassis ground (not audio ground). This tells the HU to let you switch into aux mode. When the enable line is floating (nothing plugged in), the aux button doesn't work.

Note that when there is nothing plugged in, the aux jack shorts the Left and Right input wires to audio ground (to minimize noise going into the HU). Remember this if you want to keep your OEM jack and splice in a second aux device.

To connect the OEM jack to an aftermarket HU, all you'll need are pins 3 (Left), 4 (Right), and 11 (Ground).

BT Microphone Input

We've discovered (see posts below) that the OEM mic is inside a module with a small amplifier circuit. It is not directly compatible with aftermarket HUs.

The car's harness connects Mic Detect (Subaru pin 10, labeled "MIC DET" on the HU's circuit board) to ground. I suspect this tells the HU to enable handsfree functions.

The HU's Pin 2 (what I previously called Mic Detect A -- misleadingly labeled "MIC DET" on the circuit board) sends +5V to power the mic module.

Pin 1 is the audio signal (+) from the mic to the HU. Pin 9 is the ground for the mic and its amp circuit. See pictures and posts below.

Subwoofer Output (not functional on this Impreza HU)

The sub out is the same as on the Impreza/Forester Navi HU and some recent Forester non-nav HUs. The output is balanced (differential) mono. It is not left and right stereo.

To connect to an amplifier that doesn't accept a balanced signal, send the HU's positive output (pin 6) and the shield (pin 13) to your amp's line-level input. On the Navi HUs, tying the inverted output (pin 14) to the subwoofer shield will increase the signal on the positive output. That will likely work for this HU too.

If your amp has two inputs, you may need to use a Y adapter to feed the OEM HU's positive sub out into both of the amp's inputs. Do not connect both of the HU's outputs into separate inputs on the amp -- the signals will cancel each other out, and you won't hear anything.

Pin 5 is a standard amp remote turn-on (has +12V when your HU is on). You can use this for a speaker amplifier or other accessories. Watch your current draw -- I recommend staying under 200mA total. If in doubt, use a relay with a low-current coil (not one of those monster 30 Amp automotive relays).

It's a good bet that the aux/mic harness in some 2011 Forester models will have wires on the subwoofer pins.

It looks like the Impreza HUs don't get the sub output. So the upcoming subwoofer accessory for Imprezas will probably have a T-harness that taps into a pair of the main speaker outputs

[Chayse]

Cool. I'll need this to wire in the factory Mic for my Pioneer. If my '11 will ever get here that is.

SVXdc - so this means I only need to connect two of the three wires on the adapter I received from you?

[SVXdc]

Originally Posted by Chayse

Cool. I'll need this to wire in the factory Mic for my Pioneer. If my '11 will ever get here that is.

Well, at least you can wire up all of your harnesses while you're waiting and be ready to go.

SVXdc - so this means I only need to connect two of the three wires on the adapter I received from you?

Yes, I'm fairly sure pins 1 and 9 will be all you need. [ADDED: I was wrong. See replies below]

As for retaining OEM the USB jack, since some Canadian 2011 Imprezas have an AVIC-U310BT (see this thread), the USB adapter cable should be available as a replacement part, either from Subaru or Pioneer. Probably will be expensive, but might still be better than the time/effort/materials it would take to hack together something to plug into the car's harness or socket.

[acuracing]

I'm working on getting pictures of the mic right now. I had bought the 16-pin harness (with only three wires for the Bluetooth mic) from SVXdc previously but ended up not using it since the Clarion HU had a built-in mic on the face. I ended up returning the Clarion for various reasons and just installed a AVIC-X920BT last night and want to really use the existing OEM mic. Let's get this all sorted out ASAP. Stay tuned for pics. My wedding photography setup is missing the macro lens since a buddy is borrowing it but I will see what I can do while I take out the map light/mic housing.

[acuracing]

Okay, I was able to get some pictures of these. Forgive me if they came out blurry. Here's a link to the full gallery of everything I took pics of. The original larger sizes can be viewed here as well. Subaru Mic - a set on Flickr

Here is the view of the female map/mic harness. In looking directly at the pins, here is the color coding of the wires.



-----------
1 2 3 4
5 6
-----------

1: N/C
2: Blue
3: Red
4: Yellow
5 & 6: For map lights only...

Here is wiring of the male mic harness that leads back into the car. This is looking directly at the pins.

-----------
1 2 3 4
5 6
-----------

1: White/Black
2: Gray
3: Violet/Red
4: N/C
5 & 6: For map lights only...

Here's some shots of the inside of the mic after opening it. There isn't anything I could really see in writing on the PCB. Mainly a lot of C7, R5, etc. The white and black thin wires are for the microphone itself. I unscrewed the PCB to see if there would be anything under it and there is nothing. Simply solder joints.



And the connection.

Blue female to Violet/Red male
Red female to Gray male
Yellow female to White/Black male


Hope that helps in any way.

-Mike

[SVXdc]

Thanks, Mike, for opening up your mic and uploading all of those pictures!

Here's how Subaru numbers the 6-pin connector (which they designate R56 in models without the sunroof, or R62 in models with sunroof):

Viewing pins side of car's harness plug
(or wires side of overhead console's socket):

1     2
3 4 5 6

Pin   Function    Car's wire    Map/Mic Pod
---   ---------   -----------   -----------
 1    Ground      Black         Gray      (to map lights)
 2    +12V Bat.   Blue/Green    Green     (to map lights)
 3    -           NC            NC
 4    Mic In -    Violet/Red    Blue
 5    Mic Det A   Gray          Red
 6    Mic In +    White/Black   Yellow

Here are cropped versions of your close-ups of the mic's PC board

(click to see larger images)

I've mirrored the rear view (so it's as if you can see through the front) to make it easier to trace the circuit.

Looks like quite a few resistors and capacitors, and at least one transistor. With these better-focused shots of the front and back (with the black and white wires lifted out of the way), I can try to make out the circuit.

I'm starting to wonder if the 3rd wire coming from the HU (what I'm calling 'Mic Detect A') provides a voltage to this circuit. Could be simply to power an amplification stage, or perhaps even some kind of HU-controlled variable gain.

So can someone take a voltmeter to the HU's Mic Detect A pin (pin 2 on the 16-pin aux socket) with the aux/mic harness unplugged, and see if the HU is sending out a voltage? [ADDED: A 2011 owner told me it's +5V]

Here's Sonic Electronix's page for the AVIC-U310BT (discontinued). Their close-up of the AVIC's mic shows its 2.5mm plug only has 2 pins. In the Canadian Imprezas with that AVIC as the "factory" HU, if they're connecting anything to the OEM mic's 3rd wire, either it's one of those two pins, or it's coming from somewhere else besides the HU. [ADDED: Canadian Imprezas with the U310BT use a Pioneer mic on top of the steering column. I don't know if the Subaru mic is even present in the overhead location]

[acuracing]

Here's the best I could do with the PCB of the mic. I found an old school digicam with Macro that has a battery that lasts all of a minute. Hope this helps. Unfortunately, I won't be able to test the HU output on the "Mic Detect A" wire because I do not have either a voltmeter or the stock HU at the moment.





Also, for what it is worth, the Bluetooth mic that came with the X920BT is the exact same as the U310BT.

-Mike

[SVXdc]

Excellent! I've added cropped versions to my previous post. When I have more time, I'll figure out the circuit.

Can you read anything printed on the transistor (5-pin device Q1) or on the brown-colored capacitors?

I can make out all of the resistors except maybe R6. Is that "392"?

The input wires appear to be labeled in Japanese. Can anyone translate?

There is one more label at the very bottom (between C11 and C10), and near the pads for the black and white microphone wires.

[acuracing]

Originally Posted by SVXdc

Excellent! I've added cropped versions to my previous post. When I have more time, I'll figure out the circuit.

Can you read anything printed on the transistor (5-pin device Q1) or on the brown-colored capacitors?

I can make out all of the resistors except maybe R6. Is that "392"?

The input wires appear to be labeled in Japanese. Can anyone translate?There is one more label at the very bottom (between C11 and C10), and near the pads for the black and white microphone wires.

Okay this should help answer more of the puzzle.

On the transistor, it reads (looking at the PCB head-on with the Q1 marking denoting the upper left corner of the transistor):

------
0 4 1
* 2 1
------

The numbers are actually rotated 90* CCW on the transistor itself. The asterisk is actually more of a "dot" from what I could tell with my loupe.

There are no markings I can make out on any of the brown capacitors. They simply look blank.

R6 is indeed "392".

-Mike