These instructions apply to the Subaru Forester Mk2 (SG) 2002-2008.
For other models, please choose your vehicle here.
Like the airbag system, the anti-lock brake (ABS) system on the second-generation (SG) Subaru Forester stores its faults as a two-digit flash code that the ABS warning light blinks out — it is not read through the OBD-II port. You put the system into diagnostic mode by grounding one pin of the same under-dash diagnosis connector, then count the flashes. This guide covers reading the ABS code, what each number means, and clearing the memory after a repair.
Brakes are safety-critical. Reading the code is non-invasive, but an illuminated ABS light means the anti-lock function is disabled — ordinary braking still works, but the wheels can lock under hard or slippery braking. Clearing the memory does not repair anything; if the light returns, the fault is still present. Have any ABS fault properly diagnosed and repaired.
Why the ABS light needs the flash method
A generic OBD-II scanner reads the engine/emissions system, not the ABS control module. On the SG Forester the ABS module reports through its own warning light using the diagnosis connector, so the code has to be blinked out and counted by hand — exactly the same idea as the airbag (SRS) flash code, but on a different connector pin and with its own set of codes.
Read the ABS flash code
The diagnosis connector sits at the side of the driver’s seat, under the instrument-panel lower trim. You will use terminal 6 and a ground terminal.
- Take the diagnosis connector out from the side of the driver’s seat.
- Turn the ignition switch OFF.
- Connect diagnosis connector terminal 6 to the ground terminal.
- Turn the ignition switch ON. The ABS warning light enters diagnostic mode and begins to blink.
- Read the flashes. A long flash (1.2 seconds on) counts as a “ten”; a short flash (0.3 seconds on) counts as a “one”. The light shows the start code 11 first, then the stored fault codes with the most recent shown first, repeating for up to about three minutes.
Reading it: the start code 11 is one long flash plus one short flash. A fault such as code 24 is two long flashes plus four short flashes. If only the start code (11) is shown, there is no fault stored in memory. The module keeps up to the three most recent codes until they are cleared.
ABS flash-code list — SG Forester
| Code | What it points to |
|---|---|
| 11 | Start code — shown first; shown alone when no fault is stored |
| 21 | Front ABS wheel-speed sensor (RH) — open circuit or input voltage too high |
| 23 | Front ABS wheel-speed sensor (LH) — open circuit or input voltage too high |
| 25 | Rear ABS wheel-speed sensor (RH) — open circuit or input voltage too high |
| 27 | Rear ABS wheel-speed sensor (LH) — open circuit or input voltage too high |
| 22 | Front ABS wheel-speed sensor (RH) — abnormal sensor signal |
| 24 | Front ABS wheel-speed sensor (LH) — abnormal sensor signal |
| 26 | Rear ABS wheel-speed sensor (RH) — abnormal sensor signal |
| 28 | Rear ABS wheel-speed sensor (LH) — abnormal sensor signal |
| 29 | Abnormal signal from any one of the four wheel-speed sensors |
| 31 | Inlet solenoid valve, front RH (in the ABS control module / hydraulic unit) |
| 32 | Outlet solenoid valve, front RH |
| 33 | Inlet solenoid valve, front LH |
| 34 | Outlet solenoid valve, front LH |
| 35 | Inlet solenoid valve, rear RH |
| 36 | Outlet solenoid valve, rear RH |
| 37 | Inlet solenoid valve, rear LH |
| 38 | Outlet solenoid valve, rear LH |
| 41 | Abnormal ABS control module |
| 42 | Source (supply) voltage is abnormal |
| 44 | Fault in combination with the automatic transmission control |
| 51 | Abnormal valve relay |
| 52 | Abnormal pump motor and/or motor relay |
| 54 | Abnormal stop-light switch |
| 56 | Abnormal G-sensor output voltage (models fitted with a G sensor) |
Codes 21–29 point to the wheel-speed sensors and their wiring — a common cause of an ABS light, often just a damaged sensor or a corroded connector at one wheel. Codes 31–38 and 41–56 point inside the hydraulic unit and its supply.
Clear the ABS memory after repair
Only clear the codes once the fault is actually fixed. With a code called up (terminal 6 still grounded and the light blinking):
- Disconnect terminal 6 from the ground terminal.
- Within about 12 seconds, connect and disconnect terminal 6 to the ground terminal three times, holding each connection for at least 0.2 seconds.
- Confirm the memory is clear — after clearing, the ABS light should show only the start code (11).
Frequently asked questions
Can I read a Subaru ABS light with an OBD-II scanner? Not on the SG Forester — the ABS module reports through the flash-code method above, on diagnosis-connector terminal 6, not through the OBD-II port.
The light shows only 11 — is that bad? No. Code 11 on its own is the start code with no stored fault. If your ABS light is off during normal driving, the system is healthy.
My ABS and brake lights are both on. That often points to a wheel-speed sensor or the supply/relay side rather than the hydraulic valves. Read the code first — a single sensor code (21–29) is usually a much smaller job than an internal hydraulic-unit fault.
Is it safe to drive with the ABS light on? The normal brakes still work, but the anti-lock function is disabled, so the wheels can lock under hard or slippery braking. Drive gently and get it fixed.
If the airbag (SRS) light is on too, that system uses the same flash-code method — see how to read the airbag (SRS) flash code.
Need to look up a brake or chassis trouble code on your Subaru? Our sister site autodtcs.com covers diagnostic trouble codes.
Independent guide — not affiliated with Subaru. Always follow your official service manual and safety precautions. Read our full disclaimer.