Welcome to the North American Subaru Impreza Owners Club Friday February 26, 2021
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
Go Back   NASIOC > NASIOC General > Car Audio, Video & Security

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.

* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Thread Tools Display Modes
Old 12-14-2020, 03:23 PM   #1
Scooby Newbie
Member#: 265148
Join Date: Nov 2010
Location: MA
2001 Legacy

Default How to Swap in a 2019 Harman Kardon OEM Apple CarPlay Head Unit to a 15-18 WRX

This will be a tutorial for those looking to retrofit the CarPlay / Android Auto radios that come with the 2019+ WRX. This guide is a bit long winded but anyone looking to do this should consider getting a much info as they can before starting work. In short, the swap is rather easy, you just need to build an adapter harness between the 2016-2018 AMP connections in the trunk, to a pigtail from a 2019+ AMP.

Final Pic

I previously swapped in a 2019 WRX radio into my 2013 Crosstrek and now wanted the same experience in my 2016 WRX. Though the Nav in the '16 Rex is worlds better than the '13 XV, it's still clunky and lackluster compared to using a modern smartphone. I could have done what many of you did and purchased an aftermarket double DIN radio, or one of those Android units, but aftermarket radios have never been my thing. I always thought the bezel around single/double DIN radios looked tacky and took away from the interior. Even the Seicane android units jet out like someone glued a tablet screen onto a bezel and I've had issues such as poor FM reception or UI lag when trying those in the past. Completely fine if you went that route, they are just personally not for me so I wanted to swap in an OEM radio. I was specifically looking for a MAP button radio to retain factory Nav. Why would I want this with CarPlay? Well there are times I travel to some pretty remote areas that lack cell service. Carplay is great but I didn't want to be stranded in a dead zone with no GPS. With the factory Nav (which is worlds better on the '19 than the '16) I will always have a map irregardless of my cell reception. My '16 WRX also has HK Audio with the factory Amp & Sub. Swapping in a 2019 MAP button radio will allow me to retain this as well. I set up an eBay search back in 2018 and combed car-part.com regularly hoping someone would list one. In May of 2020 I finally found one for my crosstrek, and in August of 2020 found another for my WRX. I would commonly see auctions for the 6" & 7" PHONE button radios but the MAP HK radio is much rarer radio only included on 2019 - 2020 WRX/STI's with Leather.

Parts List
  • Radio 86471VA610 / 86471VA710 / 86481VA730 (MAP) - 86471VA620 (PHONE) 19-20 WRX w/ Pigtails
  • Amplifier 86221va050 19-20 WRX w/ Pigtails
  • Wire 18Ga 20 Colors 1FT
  • Wire 22Ga 11 Colors 1FT
  • Backup Camera 86267VA510 17-20 WRX
  • USB Jack 86257SJ131 2019-2020 WRX XV Impreza Outback Forester Legacy
  • Steering Wheel Controls 83154VA300
  • Axxess AX-TOYCAM3 Harness
  • AutoHarnessHouse.com Toyota Factory Amp Upgrade harness Item # 4438

Level Setting:
To start my WRX, as mentioned above, was a 2016 with factory Nav. My goal is to build a short adapter harness between the trunk connectors and the amplifier. The 2019 WRX Amp uses a completely different connector than the 2015-18. Not only that, but the amp itself was completely redesigned on the inside. This means you can't simply swap in a 2019 radio and expect it to talk to the 2016 amp. Between the 2015-2020 WRX years Subaru actually redesigned the HK amplifier 3 times and the pinouts for each are different. If you have a WRX with the base radio, and want to add a 2019+ Nav radio, this swap will be harder and you are probably better off following my tutorial for the Crosstrek as the pinouts between the HK Audio & non-HK cars are also different. This guide will assume you are going from a 2016-2018 WRX with Nav, to a 2019-2020 Nav Radio with a MAP button, but those in different boats looking to do the same should be able to take the tips here and apply them to their own situation. For the 2015 guys, referring to the service manual I noticed that two data lines pin7 & pin8 on connector R386 are not present on the 2015 models. You could solve this by running two wires all the way from the amp to the radio, but a short harness like the one I built wouldn't be possible.

When looking for parts such as the radio and Amp, I can't stress this enough, ASK FOR THE PIGTAILS!!! Most of these connectors are proprietary, you could try reaching out to autoharnesshouse.com & ae64.com but it's much easier to have the junk yard include them with the radio/amp. You can certainly hack up your harness if you'd like to, but my method was to not make a single cut in existing factory wires.

So you have all the parts, now what? If you are just wanting CarPlay / Android Auto and are fine with a PHONE button radio you can skip most of this guide and just reference items such as the camera section and the door switch wiring, you won't need to build an adapter harness as I do below. Assuming you are up for the challenge of upgrading to a 2019 MAP radio you'll need to start soldering. On the 15-20 WRX/STI's with HK audio there will be an Amplifier mounted in the trunk. The radio sends L/R channel audio to the amplifier as well as several data signals. The amplifier then interprets that and individually drives each speaker, which for the HK WRX have their wires leading to the trunk of the car. What we need to do is build a translation harness between the amp and the trunk wires so that we can leverage the existing wiring in the 2016 WRX, but allow the 2019 Amp to drive the speakers.

Pic comparing the '16 amp connectors to the harnesses mentioned above

The harness is essentially a re-mapping exercise. Using the service manual radio pinouts from the 2019 & 2016 WRX, I had to study both to see what pin each signal was coming in at the source (trunk harness) and where is needed to go at the destination (2019 Amp). Both manuals are available on Subaru TechNet which is $35 for a 3-day pass. I included the bits I used here, but if you need more info it's easy to grab the full PDF. I believe after everything it was just over 30 short wires that I had to re-map.

At this point you may already be overwhelmed. Once you get going it's actually pretty simple, there is nothing special going on, just connecting wires from A to B where they need to go based on the manual. Once you have all the re-mapping work planned out it's time to bust out that soldering iron. All of the wires in the harness I built were soldered and heat shrunk wrapped. This part was actually pretty relaxing spending an hour so after work each night one by one soldering connections at my dining room table. Color coding is optional but makes things easier. I bought a pack of 11 different colors of 22Ga wire which was used for the data lines going from the radio to the amp, and a pack of 20 different colors of 18Ga wire which was used for the wires going to the speakers. I had some colors left over but can't remember how many. The length I chose for the harness from trunk connectors to amp was between 6-in to 1ft so it would tuck up nicely without stressing any wires.

Pics of the harness before wrapping

In the manual you will notice that 6 of the data lines (A5, A4, A3, A2, B23, B22) are shielded, it was recommended wrapping these lines in foil tape, connecting that tape to the wire from the the ground pin (24-pin No 6 in this case), then wrapping in pipe thread tape (I used the thicker yellow oil type), and finally a layer of electrical tape as a DIY shield which I did, but given the short length may not be necessary. The data lines will go from the 24-pin connector in the trunk to the amp, and the speaker lines go from the 12 & 10-pin connector in the trunk to the pigtails included with the amplifier.

Pic showing the harness wrapped up, note the foil tape

For harness I did not want to cut or splice the factory wires in any way so I used a "Toyota Factory Amp Upgrade harness" Item # 4438 by AutoHarnessHouse.com which is the same as the 12 & 10-pin connectors on the 2015-2018 amps, as well as an Axxess AX-TOYCAM3 Harness which is the same as the 24-pin connector, allowing me to mate right up to the trunk harness, and making the whole project completely reversible should I ever go back to the stock 2016 radio.

Pic of the translation harness installed in the car between the '16 wiring and the '19 amp

You will also need to swap to a newer camera part # 86267VA510. While my 2016 Camera displayed the video fine, it would not show the guide lines. THe solution was to swap in the newer camera and voilla my lines were back. The conenctor is the same so no splicing or adapters needed here, just remove the old camera (if you have a 15-16 rex) and swap in the new.

To use Android Audo / Apple CarPlay you will need to upgrade the USB jack. The stock one only outputs enough power for a slow charge, where as the 2019+ part # 86257SJ131 supplied 2.1A to the phone so it doesn't die while operating. The jack fits into the center console directly where the existing one is and the harness in my 2016 plugged right in so again just remove and replace with the newer part.

Pic of the 2.1A USB jack

The Steering wheel controls you will notice are now all mapped incorrectly. List is Vol Up & Back is now Vol Down etc. I actually passed on this for now but to correct these you will need to obtain the 2019+ Steering Wheel controls part# 83154VA300, remove the steering wheel including the airbag, and swap in the new buttons. I'll mess around with many things but I always hesitate at safety equipment. For now I am using the existing controls and just have to remember which buttons do what now until I either get brave enough to remove my airbag, or Subaru has another airbag recall at some point like they did for the older model cars and I can do it then before bringing it in .

The new 2019+ Radios also have a new feature where they will remain on after the car has turned off until the driver door is opened. For this you will need to run a single wire from the head unit to the driver door switch. The factory wire goes into pin 1 of the door switch which when de-pressed is ground. There was an empty spot on pin 2 which using a multimeter I also determined functioned the same grounding when the switch was opened. I previously removed any connectors not used on the pigtail harnesses mentions above, so I took one of the removed pins and fit it into slot 2 of the door switch. I ran the other end of this under the door jam trim to a single blue wire coming out of the 12-pin pigtail on the radio. This was the ONLY wire I needed to run to the back of the radio for this swap meaning that the only pigtail you NEED to get when buying a 2019 radio is that 12-pin connector. Without this the radio will stay on for 3 minutes each time you turn off the car, annoying but not unusable if you decide to skip this step.

Pic of he back of the radio, note the new single blue wire I ran to the door switch. All other connectors plug in as-is.

My 2016 rex didn't have the Telematics kit so I just removed the unit from the radio and haven't noticed any issues but you 2017+ guys may have to read into that to confirm nothing extra is needed.

I may be forgetting some but here is a mapping of the wires

2016 Trunk Harness -> 2019 Amplifier
24-Pin No 5 -> 28-Pin Black No 7 (R+)
24-Pin No 3 -> 28-Pin Black No 6 (L+)
24-Pin No 12 -> 28-Pin White No 8 (ACC)
24-Pin No 4 -> 28-Pin Black No 21 (R-)
24-Pin No 2 -> 28-Pin Black No 20 (L-)
24-Pin No 23 -> 28-Pin White No 7 (INT/IL1+)
24-Pin No 22 -> 28-Pin White No 21 (INT-/IL-)
24-Pin No 8 -> 28-Pin White No 6 (CAN+/TX+)
24-Pin No 7 -> 28-Pin White No 5 (CAN-/TX-)
24-Pin No 6 -> Foil Tape Shield
10-Pin No 1 -> 28-Pin White No 12 (+B/Power)
10-Pin No 5 -> 28-Pin White No 15 (+B/Power)
12-Pin No 6 -> 28-Pin White No 25 (GND)
12-Pin No 7 -> 28-Pin White No 28 (GND)

2016 Trunk Harness <- 2019 Amplifier
10-Pin No 3 <- 28-Pin Black No 1 (FR+)
10-Pin No 8 <- 28-Pin Black No 3 (RR+)
10-Pin No 2 <- 28-Pin Black No 13 (RL+)
10-Pin No 10 <- 28-Pin Black No 15 (FL+)
10-Pin No 9 <- 28-Pin Black No 16 (FR-)
10-Pin No 7 <- 28-Pin Black No 18 (RR-)
10-Pin No 6 <- 28-Pin Black No 26 (RL-)
10-Pin No 4 <- 28-Pin Black No 28 (FL-)
12-Pin No 2 <- 28-Pin Black No 2 (TWR+)
12-Pin No 9 <- 28-Pin Black No 14 (TWL+)
12-Pin No 1 <- 28-Pin Black No 17 (TWR-)
12-Pin No 3 <- 28-Pin Black No 27 (TWL-)
12-Pin No 4 <- 28-Pin Black No 12 (WF1+)
12-Pin No 10 <- 28-Pin Black No 25 (WF1-)
12-Pin No 5 <- 28-Pin Black No 4 (WF2+)
12-Pin No 12 <- 28-Pin Black No 19 (WF2-)

2019 Radio -> Door Switch
12-Pin No 4 -> 3-Pin No 2 (Switched GND)

Attached are the Sections from the 2016 & 2019 Service Manuals that I referenced.

NOTE: On the page showing the 2019 Amp connectors, they show the amplifier plastic side down with connector (A) R386 being on the left and connector (B) R316 on the right. This is actually INCORRECT in the service manual. (B) which is the black connector is actually on the left, and (A) the white connector is on the right.

CarPlay Waze Nav on the Radio

2019 WRX FSM Section: https://od.lk/f/MjRfMjk1Nzg2NjJf
2016-18 WRX FSM Section: https://od.lk/f/MjRfMjk1Nzg3NTNf

If you want to do any deeper reading see my tutorial for the Crosstrek here: https://www.subaruxvforum.com/thread...d-unit.177571/
* Registered users of the site do not see these ads.

Last edited by protivakid; 12-19-2020 at 05:44 AM.
protivakid is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 12-14-2020, 05:26 PM   #2
Scooby Specialist
Member#: 94408
Join Date: Aug 2005
Chapter/Region: E. Canada
Location: Canada
17 STI Sport-Tech
20 Corolla Hybrid Premium


Awesome write-up. Interesting about the amp differences and revisions.. strange they did that.

I was wanting to do all this, but had such a hard time getting the proper wiring diagrams for the 19+, and used HUs were hard to come by in Canada (new was way cost prohibitive up here). I decided to just live with my 17 HU considering I picked up a dd with CarPlay, and my STI has become the weekend car.

Anyway, thanks for being so dedicated to this. Iím sure it will help many others. Great job.
littledrummerboy is offline   Reply With Quote
Old 12-18-2020, 05:40 PM   #3
Scooby Newbie
Member#: 447706
Join Date: May 2016
Location: Greenville, SC
2017 WRX Base


This is awesome! Thanks for writing this up.
waltersh is offline   Reply With Quote
Old 12-29-2020, 03:36 AM   #4
Scooby Newbie
Member#: 446616
Join Date: May 2016
Chapter/Region: MWSOC
Location: Ohio, USA
2018 WRX Limited
Lapis Blue Pearl


Many thanks for putting this information out there. Been wanting to do this for awhile now, hoping to find a good price on the head unit.
andrew_l_s is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 03:49 PM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.