Drive by Cable to Drive by Wire Conversion for Subaru

This blog post describes the basics of how to update the cable throttle (drive-by-cable) to an electronic throttle (drive-by-wire) in a Subaru. Not sure if your car is cable throttle or electronic throttle? Check here. Unfortunately, we can't give a full wiring write-up for this conversion since there are so many variations, but we can list the step-by-step basics of what will need to be updated in the car.

If you use an OEM ECU, you must also swap the engine to match.

This conversion can only happen if the new engine platform is a drive-by-wire because the ECU must match the engine. This blog post goes into more detail about how to pick the correct parts for your project

https://iwireusa.com/blogs/iwire-university/this-dictates-that-iwire-rules-of-thumb

If you are using a standalone ECU, you can swap parts without the restrictions of the stock ECU since it is customizable however you want.

It comes down to updating three components:

1. Updating the throttle body on the engine.

2. Wiring the new throttle body to your ECU.

3. Updating the throttle pedal and mounting it (Find our bracket for this here).

4. Wiring the new throttle pedal to your ECU.

The necessary connectors for this can be found in the links below.

Updating the Throttle Body in a Subaru

The cable for the throttle is attached to the throttle body, which is attached to the engine. To update the throttle body in a Subaru is relatively simple. It is attached to the new engine being installed. The other piece of this conversion is removing the cable for the throttle from the car, which runs from the old throttle body to the old pedal. To do this, unbolt the cable by removing the clip attached to the pedal and the engine. Then, pull the throttle cable out of the engine bay and into the car through the firewall grommet.

Connecting the New DBW Throttle to the ECU

If you've done a merge with iWire, then you can skip this step and plug the harness back into the ECU and the new pedal. If you went a DIY route, wire the DBW Relay to the ECU. We can't give specific pin information here because it changes so much between car models and years. Find a diagram specific to your car's model and year for this information. Below are links to standard DBW plugs needed for this conversion.

Updating the DBW Throttle Pedal

To update your pedal, remove the two bolts that currently hold it in place and pull it out. Then mount our iWire DBW Pedal Adapter Plate into place. (You'll want this bracket because the mounting points for the cable throttle pedal are different than the DBW pedal). Next, bolt the new DBW pedal onto the mounting plate, and you're good to go. We have posted our install video below if you're more of a visual person.