Disconnect and Reconnect the Battery

Reviewed by the Service Reset editor · Updated August 9, 2026 · How we verify
Quick referenceTools10 mm spannerTime~15 minMethodDisconnect negative terminal first

These instructions apply to the Alfa Romeo Tonale Mk1 (965) 2022-Present.
For other models, please choose your vehicle here.

Disconnecting the 12 V battery on your Alfa Romeo Tonale (2022–present) — for a new battery, winter storage, or work near the airbags — is straightforward, but there’s one thing to know first: the Tonale is a 48 V mild hybrid, so it has two batteries. You only ever touch the 12 V one.

Alfa Romeo Tonale Mk1 — the vehicle covered in this guide.
Alfa Romeo Tonale Mk1. Photo by Mr.choppers via Wikimedia Commons, licensed CC BY-SA 3.0.

Two Batteries — Touch Only the 12 V

  • 12 V battery — in the engine compartment. This is the one you disconnect and replace, exactly like an ordinary car battery.
  • 48 V battery — under the centre console. This is the mild-hybrid pack — leave it alone. It is not an owner-serviceable item.

The PHEV (Plug-in) Tonale also has a separate high-voltage traction battery — again, never touch its orange cabling. For all the jobs below you work only on the 12 V battery in the engine bay.

Disconnecting Safely

  1. Note your radio code and presets, then switch everything off.
  2. Disconnect the negative (−) terminal first, then the positive.
  3. Working near airbags or seat-belt pretensioners? Wait a few minutes after disconnecting before such work.

Reconnecting and Re-initialising

Reconnect positive first, then negative. The Tonale then relearns:

  • Power windows — one-touch may need re-initialising (hold the switch fully up/down at the limit).
  • Electric boot lid and sunroof (if fitted) relearn their travel.
  • Start/stop and steering-angle settle after a short drive; re-enter clock and presets.

If Something Isn’t Right Afterwards

  • Warning lights often clear after a short drive once the relearns complete.
  • A persistent light stores a code — look it up on autodtcs.com.
  • Fit the correct 12 V battery type — the mild-hybrid system is fussy about battery spec.

Frequently Asked Questions

Where is the battery on an Alfa Romeo Tonale?

The 12 V battery is in the engine compartment; the 48 V mild-hybrid battery is under the centre console and is not owner-serviceable.

Can I disconnect the 12 V safely on the mild hybrid?

Yes — the 12 V is separate from the 48 V and (on the PHEV) the high-voltage system; never touch those.

Which terminal first?

Negative (−) off first, reconnect it last.

Do I need to recode anything?

Windows/roof/boot may need a one-touch relearn, and you’ll re-enter the clock and presets.

If a warning light stays on after reconnecting, look up the code on autodtcs.com.

Independent guide — not affiliated with Alfa Romeo. Always follow your official service manual and safety precautions. Read our full disclaimer.

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