These instructions apply to the Subaru Forester Mk5 (SK) 2019-Present.
For other models, please choose your vehicle here.
Disconnecting the 12 V battery on your Subaru Forester (2019–present) — the fifth-generation SK — is a straightforward job most owners can do at home with one spanner. You might do it to fit a new battery, to lay the car up over winter on a maintenance charger, or to safely isolate the electrics before working near the airbags. Provided you disconnect and reconnect in the right order, the Forester wakes up cleanly and relearns the handful of settings it briefly forgets, so there is no reason to be nervous about it.
Where the 12 V Battery Is
On the SK the 12 V battery is in the engine compartment, under a cover. Lift the cover to expose the two terminals: the negative (−) post takes the black earth lead and the positive (+) post takes the red lead, usually under a red plastic flap. Be sure which post is which before you touch a spanner to anything.
If yours is the e-Boxer mild hybrid, remember it is a two-battery car. There is a separate high-voltage battery under the boot floor, wired in bright orange cabling, and that system is off-limits for home work: never touch the orange high-voltage cabling. Everything here concerns only the ordinary 12 V battery, which is safe to handle.
Getting Ready
- Switch the ignition fully off and make sure the car is not in its READY state.
- Keep every keyless transmitter well away from the car, outside range, so it cannot wake and re-power the circuits.
- Close the doors and tailgate, and switch off the lights, climate and any accessories so nothing is drawing current.
- Note your radio presets and, if the car uses one, your audio security code.
- Give the control modules a couple of minutes to power down before you loosen a terminal.
- Have the right spanner ready, and wear gloves and eye protection.
Disconnecting
- Switch everything off, and keep keyless transmitters well away from the car so it cannot wake up.
- Slacken the clamp and disconnect the negative (−) terminal first, then move the earth lead clear so it cannot fall back onto the post.
- Now slacken and lift off the positive (+) lead.
- If you are working near the airbags or seat-belt pretensioners, wait a couple of minutes after disconnecting before starting that work.
Reconnecting
- Refit the positive (+) lead first and tighten its clamp.
- Refit the negative (−) earth lead last and tighten it.
- Check both clamps are secure — a loose terminal causes flickering electrics and false warnings — then close the cover.
What You’ll Need to Reset Afterwards
Once power is restored the Forester needs a few items settling:
- Clock and radio presets — re-enter them, plus the audio code if prompted.
- Power windows — if the one-touch function is lost, hold each switch fully up and then fully down at the limits to relearn it.
- Steering-angle and EyeSight driver-assistance systems settle after a short drive on a clear, well-marked road.
- Seat and mirror memory, where fitted, may need re-storing.
- A new battery should be a like-for-like unit of the correct specification for your model.
If a Warning Light Stays On or the Car Feels Off
- Check both clamps are tight and clean — a poor connection is the most common cause of odd behaviour.
- Let the car relearn over a gentle drive; many lights, including EyeSight-related ones, clear once the systems recalibrate.
- Re-do the window relearn if one-touch has stopped working.
- If a light stays on, rule out a genuinely tired or flat battery and read any stored code — look it up on autodtcs.com.
Frequently Asked Questions
Where is the 12 V battery on a Subaru Forester (2019 on)?
In the engine compartment, under a cover. On the e-Boxer mild hybrid the high-voltage battery is separate and sits under the boot floor — never touch its orange cabling; you only ever work on the 12 V battery.
Which terminal do I disconnect first?
Always the negative (−) terminal first, and reconnect it last. On reconnection the positive (+) goes back on first, then the negative. This keeps the risk of a short against the body to a minimum.
What needs resetting afterwards?
Re-enter the clock and radio presets, relearn the one-touch windows if they stop working, and let the steering-angle and EyeSight assistance systems settle over a short drive. Seat and mirror memory may also need re-storing where fitted.
How long should I wait near the airbags?
Give it a couple of minutes after disconnecting the battery before working on the airbags or seat-belt pretensioners, so the restraint system has fully discharged.
Will disconnecting the battery reset the service light?
No. The service reminder is stored separately and is not cleared by pulling the battery — that needs the proper service-reset procedure. Disconnecting may clear some transient fault codes, but a genuine fault will simply log again.
Can I jump-start it instead of disconnecting?
If you only want to recover a flat battery, a careful jump-start avoids the disconnect. Disconnecting is for renewing the battery, winter storage on a charger, or isolating the electrics for work near the airbags.
If a warning light stays on after reconnecting, read the stored code and look it up on autodtcs.com.
Independent guide — not affiliated with Subaru. Always follow your official service manual and safety precautions. Read our full disclaimer.