Harness Modification for Subaru Outback JDM 2021-2024 #18
Description
I have a Subaru Outback, MY2022, Australian model. The Eyesight Camera plug where the Comma harness goes is a 24-pin connector like the Subaru C and D harnesses. When attempting to use a D-harness the car immediately errors on startup, with Eyesight, ADB and a couple of other errors on the dash. This is before any attempts to use the Comma. The pinout on the Eyesight plug is different in wire count and wire position to the D-harness (and the C-harness).
Consulting the service manual for the car and comparing the pin-out to the Comma D-harness gives this table:
| Pin | D-Harness | Colour | Goes to | Subaru Label |
|---|---|---|---|---|
| 1 | CAN2_L |
Green | comma | (H)_A/S CAN_L |
| 2 | CAN1_L |
Blue | comma | P/U1 CAN_L |
| 3 | ||||
| 4 | PT11 |
blue/white | pass-through | |
| 5 | PT4 |
purple | pass-through | HRLY |
| 6 | LIN |
|||
| 7 | PT2 |
white | pass-through | CRG |
| 8 | PT1 |
grey | pass-through | GND |
| 9 | IGN |
brown | comma | IG |
| 10 | 12VIN |
red | comma | +B |
| 11 | GND |
black | comma | GND |
| 12 | PT3 |
yellow | pass-through | HTHR |
| 13 | CAN2_H |
orange | comma | (H)_A/S CAN_H |
| 14 | CAN1_H |
pink | comma | P/U1 CAN_H |
| 15 | ||||
| 16 | PT12 |
grey/white | pass-through | |
| 17 | ||||
| 18 | ||||
| 19 | PT10 |
green/white | pass-through | CR+ |
| 20 | PT9 |
purple/white | pass-through | CRM |
| 21 | PT8 |
brown/black | pass-through | IG |
| 22 | PT7 |
red/black | pass-through | GND |
| 23 | PT6 |
purple/brown | pass-through | +B |
| 24 | PT5 |
white/black | pass-through | THRG |
The required config is very close to the D-Harness:
- Comma D-harness has pins 4 and 16 as pass-through where these pins are empty on the Eyesight plug.
- The Eyesight plug has a wire on pin 6 (labelled
LIN) which goes to the steering wheel harness. This pin is empty on the Comma D-harness.
The C-harness is substantially different in pinout to my car.
For the D-Harness to work with the MY2022 AU Outback it requires an additional pass-through wire on Pin 6. I tested this by removing a wire from a 2nd harness and adding it to the D-harness. This worked, eliminating the errors on car start-up. I was subsequently able to use the Comma 4 after installing fork jacobwaller/master to handle fingerprinting.
From the manuals, it appears that my harness configuration is common across 2021-2024 JDM models of the Outback & Legacy. The 2020 model uses a 16-pin harness plug as used by the B-Harness, and the 2025 has an additional set of CAN pins on the eyesight plug(labelled EYELC2). Note that the 2022 USDM Models (officially supported) use a B-harness.
I would love to see this problem solved for more users who own my car model. Options I can see include:
- Modify the exiting D-harness spec to add an additional pass-through wire on Pin 6. As this pin is currently empty there should be no impact on existing D-harness compatible models.
- Create an E-harness compatible with the pinout on these models & leave the D-harness as-is.
- Deprecate the D-harness and replace it with an E-harness which covers both sets of cars.
I can provide some photos of the Eyesight plug in my car if needed.