Immobilizer Options in a Subaru Swap
Updated: Apr 29
In this blog post we go over the options for installing the immobilized ignition cylinder in a Subaru swap. The most important part is getting all of the necessary pieces from the same car. If all of the pieces are not from the same car, the immobilizer system will not work. Check out our other immobilizer blog post for more details on how the immobilizer system functions.
There are basically two options when it comes to updating the ignition cylinder in a Subaru. Either use the ignition cylinder and key to start the car, or tuck the key behind the dash and ignore it.
Option 1A (recommended): Swapping the ignition cylinder to the original column
Remove the ignition cylinder from the immobilized column and bolt it to the original column that came with the car being swapped. This keeps all of the other connections to the car like the Airbags the same. If the turbo steering rack is used (only recommend to do this for direct mount racks like 05+ STi) then the steering rack spline pattern is different than the RS knuckle. To solve this a custom adapter is needed which can be purchased from L&E Fabrications.
Option 1B: Swapping the entire steering column
Alternatively the entire column can be swapped. This would be fine for 2004-2005 STi column because they use a single charge Airbag. The 06+ columns could present an issue because they have a dual charge Airbag setup that would not be compatible with the older chassis. The steering knuckle issue here is length. The original turbo knuckle needs to be shortened to match the distance between the column and the rack of the older chassis.
Option 2 (not recommended): Mounting ignition cylinder under the dash
This option is easier to complete but can lead to problems in the long run. Basically the immobilized key is taped into the antenna (light up ring around the cylinder) and shoved underneath the dash and left alone. The problem with this solution is if the key shifts in the antenna, the immobilized key will no longer work. The key is very picky about where it sits within the antenna so if it moves, the antenna will not pick up the RFID in the key properly and the car will not start. If this route is chosen, at least put the key in the ignition cylinder so that the key will stay in place and potentially could be removed if need be.
Will my immobilized key work on the original door locks?
As is, no. The immobilized key would start the car and the original key or original keyless entry fob would open the doors. If you are adamant about having only one key for the car you can update the chassis by swapping out the door lock tumblers for the immobilizer door lock tumblers assuming you got those from the matching car. We believe they bolt up but we have not done this ourselves so we can not guarantee exact fitment. If you carry around a key ring like most people, we say save yourself the hassle and just use the two keys.
MAKE SURE YOU PLUG THIS UNIT INTO THE IMMOBILIZER CONNECTOR. THERE IS A MODULE THAT USES THE SAME PLUG LABLED "KEYLESS ENTRY" ON THE BOX. IF YOU PLUG THE KEYLESS ENTRY INTO THE IMMOBILIZER BOX YOU WILL FRY THE HARNESS AND MODULE.