Subaru Auto to Manual Transmission Conversion Basic Overview

Subaru Auto to Manual Transmission Conversion Basic Overview

Jul 7, '21

This post is a general overview of how to convert your Subaru transmission from auto to manual. We wish we could offer a product to make this simple but because of the many changes in Subaru wiring between car model and years, we can't make a product that works for everyone. This works for non Canbus cars only. For a full write-up click here!

If you are looking for us to handle the auto to manual conversion for you, click here!

Below is a video of us helping Bucky Lasek with his Auto to Manual Swap


When doing an auto to manual transmission conversion on your Subaru you have three options:

1. Do it yourself with the iWire Auto to Manual Connector Package. These packages are designed for three types of transmissions: NA, Turbo, and DCCD. We've curated the necessary plugs and terminals needed for the swap but only recommend purchasing these connector packages if you already have a lot of wiring knowledge and skill. Our connector kits are designed for professionals and experts only, not your average home DIY-er. While we would love to write out all the steps to do it yourself, there are literally so many combinations and variations we can't.


2. Find an equivalent bulkhead harness and swap it out. This option is best for your average DIY-er.


3. Remove your bulkhead harness and send it to iWire. We can customize your harness for whatever transmission you plan to use. This option is best for Subaru enthusiasts not comfortable with wiring.


Common Cars Compatible for an Auto to Manual Transmission Swap:

- All Impreza models from 2007 and earlier.

- All Legacy models from 2004 and earlier.

- All Forester models from 2008 and earlier.

- All Baja models from 2006 and earlier.


General Overview for an Auto to Manual Transmission Swap:

1. Finish all mechanical changes needed for your new transmission like shifter linkage, pedal box, clutch setup, etc.


2. Wire up the Neutral Position Switch (CN-PL02016) and Reverse Lights (CN-PL02009). Choose the appropriate plug needed for your transmission (NA 2 - 2 pin plugs, Turbo Trans 1 - 4 pin plug, or DCCD 1 - 6 pin plug). The neutral position switch requires ground input and signal to ECU. The reverse lights require key-on power source and output to the reverse lights. For the 6 pin DCCD transmission plug, 2 pins will be left empty and can later be wired to a DCCD controller.


3. Wire in the Vehicle Speed Sensor Plug (CN-PL03002-1). This requires power, ground, and signal output. More about speed sensors (they need to match the cluster) can be found here

For a standard Subaru Vehicle Speed Sensor Pin 1 (Left side from the terminal end of the plug) is signal, pin 2 is ground, and pin 3 is 12v key on power. Pin 1, the signal wire, needs to run directly inside the cabin to tie into the signal wire between the cluster and the ECU since this wire does not come into the engine bay.


4. Wire in the Starter Relay Plug (CN-PL04020) and Clutch Switch for Starter Interrupt Plug (CN-PL02015). The starter relay plug needs feed and trigger from key. The clutch switch for starter interrupt needs ground side trigger and output to starter and ECU.


5. Wire in Cruise Control Clutch Switch (CN-PL02046). This can be installed in series with the Brake pedal switch so that depressing either the clutch or brake will disengage the cruise.


6. Ground the manual (MT) identification pin at the ECU. It should be noted that the MT identification doesn't actually change the mapping to a manual. If possible, reflash the ECU to manual map. If reflashing isn't possible, then you'll need to swap to a manual ECU. Leave the transmission computer plugged in, unless you swap to a manual ABS pump in which case you can remove the auto transmission computer.

  • For turbo models with reflashing capabilities you can not use the Cobb AP to reflash from an auto to manual map. If you have a Cobb AP installed you will uninstall it first, then reflash the ECU with a manual map using Open Source software, then reinstall the Cobb AP. Since the ECU ID has changed from auto to manual the Cobb AP will recognize the ECU as a manual and install accordingly.

When looking for the MT identification at the ECU you want to find the ground wire that has the "MT" note on it. Below are 2 different variations from 2 different diagrams.

on pin 


Purchase iWire's Auto to Manual Transmission Conversion Connector Package


NA Transmission

Turbo Transmission

DCCD Transmission