Subaru Harness Conversion - ship us your wiring
  • Microsquirt harness to Subaru engine harness
  • Haltech universal harness
  • Subaru Harness Conversion - ship us your wiring

Subaru Harness Conversion - ship us your wiring

Previous Harness Customer?:

Subaru Year:


Using Subaru Auto Trans?:

Aftermarket ECM to Subaru engine harness:


  1. Remove harness from donor. Can use the connector guide: Harness Connectors -DO NOT SEND ENGINE (intake manifold), OR ALTERNATOR WIRING HARNESSES
  2. Please include this info in box: Project Info Sheet
  3. Ship to us for conversion (see step 2 for address).

Conversion of a Subaru wiring harness for a VW (Bus/Bug/Vanagon/Etc) to Subaru engine conversion. You remove the wiring harness from a donor vehicle, ship to us, and we return the modified harness ready for connection into your project chassis - Tested with labels and Instructions and ECU Backups for 05+ Subarus.


What does the engine management harness conversion include?

We remove the unnecessary wiring, splice, bench test, wrap, and label the harness for installation. A complete set of instructions are included in the box and emailed to the address used to purchase.

Can I use an Auto Trans ECU in a manual trans VW and vice versa?

Yes, however, it’s best to go with manual ECU if you have the choice. 2008 Forester, 2007 Impreza, and 2004 Legacy PZEV auto ECU won’t allow us to manually force it to manual trans (Recommended to go with MT ECU for these models).

Do you send a shipping label?

Due to the huge variance in harness sizing and destinations it makes more sense for the shipper to pay locally so we don't supply a shipping label.

Which years do you recommend?

Up to 2010 Forester/Impreza (2004 Forester turbo, 05 WRX Turbo), Up to 05 Legacy - see more here: Which Engine?

I've never pulled a wiring harness, how do I do this?

Watch the BUSARU wiring harness removal videos here: and here:

Which vehicles do you build engine management harnesses for?

Classic VW's, Porsches, Subarus, Kit Cars, Factory Five 818, Sandrails, boats, Snow Cats and on and on... nearly anything that you wish to put a Subaru engine into.

How long does the wiring harness conversion take?

Occasionally up to 4 weeks (usually 3) but can expedite with 1 week turnaround for $150 - make sure to note this on the Harness Info Sheet.

What wiring harness items do I need to pull from the donor car?

- Check here for the connectors you need to keep: Harness Connectors

- The main wiring harness under the dash.

- The Subaru computer which sits in the passenger foot rest on 1995+ cars, and is under the driver-side dash on 1990-1994 cars.

- The Ignitor, Mass Airflow Sensor, Oxygen Sensors, Atmospheric Pressure Sensor and PSSSV on passenger shock tower in engine bay (some models do not have these 2). Some models (turbo and 6cyl have a fuel pump controller that you will want to keep as well).

- If you have an OBD2 car then make sure to keep that connector (it sits in the driver-side kick panel).

- Keep the alternator harness (It can be cut at the fender, and where it enters the black relay box).

- Turbo conversions require the Fuel Pump Controller in the rear-right/left of the vehicle so grab the controller, its connector, and as much of the wiring to the connector as you can.

What do I need to send to BUSARU for wiring harness modification?

The main wiring harness under the dash (with all of it's connectors - Harness ConnectorsAND the ECU computer - you keep the sensors. engine harness (under intake manifold), and alternator harness.

I can't Identify a Subaru connector, can you help?

Yes, Please see the Subaru connectors here: Harness Connectors

What is a Code Killer?

CK is a Diagnostic Trouble Code (DTC) defeater, solving up to 9 common DTCs related to these engine swaps. This is optional and these DTC's don't affect performance of your engine although it is a good way to "clean up" your install and make your Malfunction Indicator Lamp (MIL) more useful (as it won't constantly be on and will only trigger when a critical DTC is triggered). 2005+ Code Killers defeat a lot more codes as there are many more options that can be flashed out of the ECU (see the A la carte service here: Subaru ECM Flash)

What about Cruise Control and AC?

If wanting to use the entire Subaru CC or AC system please clip the CC/AC connectors from the main harness before sending, as these are separate harnesses and not part of the engine management harness. Find the CC/AC wiring diagrams in the factory service manuals found here:

Microsquirt/Megasquirt/Haltech Wiring

We can wire your Microsquirt/Haltech ECM harness to your Subaru engine harness (found under the intake manifold). We will need the aftermarket harness and your Subaru engine harness. It's recommended that you find a local tuner shop (or learn to tune yourself), if going with the Microsquirt/Megasquirt/Haltech aftermarket ECM. This service is to physically wire the MS harness to the Subaru harness, unfortunately no tuning or support of the ECM systems/instructions are provided - simply put, this is just a wiring service. You can see much more information on Megasquirt/Microsquirt here: and Haltech here: