Disconnect and Reconnect the Battery

Reviewed by the Service Reset editor · Updated August 18, 2026 · How we verify
Quick referenceTools10 mm spannerTime~15 minMethodDisconnect negative terminal first

These instructions apply to the DS 9 Mk1 (X) 2021-Present.
For other models, please choose your vehicle here.

Disconnecting the 12 V battery on your DS 9 (2021–present) — for a new battery, winter storage, or work near the airbags — needs one extra step most cars don’t: a wait for the body computer (BSI) to go to sleep before you pull the terminal. The DS 9 is mostly an E-Tense plug-in hybrid, so there’s also a high-voltage system you must leave alone.

Find the Battery First

The 12 V battery is in the engine compartment. On the E-Tense plug-in hybrid, the high-voltage traction battery is separate — never touch the orange high-voltage cabling; you only ever work on the 12 V battery. Note your radio security code and presets before you start.

Disconnecting Safely (BSI Sleep)

  1. Turn the car off and remove the key from the ignition.
  2. Close the windows, then lock the car with the mechanical key and close all the doors.
  3. Wait 6 minutes so the BSI body computer powers down fully.
  4. Disconnect the negative (−) terminal first, then the positive.
  5. Working near airbags or pretensioners? Wait a few minutes after disconnecting before such work.

Reconnecting and Re-initialising

Reconnect positive first, then negative. The DS 9 then relearns:

  • Power windows and sunroof — one-touch needs re-initialising (see our DS 9 window-reset guide).
  • Remote control may need a quick re-sync.
  • Re-enter the clock and presets.

If Something Isn’t Right Afterwards

  • Warning lights often clear after a short drive.
  • A persistent light stores a code — look it up on autodtcs.com.
  • Fit the correct 12 V battery type — the stop/start and hybrid systems are fussy about spec.

Frequently Asked Questions

Where is the 12 V battery on a DS 9?

In the engine compartment. The E-Tense high-voltage battery is separate — never touch its orange cabling.

Why wait 6 minutes before disconnecting?

So the BSI body computer goes to sleep — pulling the terminal while it’s awake can corrupt stored settings.

Which terminal first?

Negative (−) off first, reconnect it last.

What needs resetting afterwards?

Windows/sunroof need a relearn, the remote may need a re-sync, 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 DS. Always follow your official service manual and safety precautions. Read our full disclaimer.

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