These instructions apply to the BMW 1 Series Mk3 (F40) 2019-Present. For other models, please choose your vehicle here.
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Unlike the rear-wheel-drive BMWs that hide the battery in the boot, the BMW 1 Series Mk3 (F40, 2019–present) is front-wheel drive and keeps its 12 V battery in the engine bay. The one thing that’s the same as every modern BMW: a new battery should be registered. This guide covers safe disconnection and that step.
Where the Battery Is
The 12 V battery is in the engine compartment, under a cover (the F40 shares its front-drive platform with the MINI and 2 Series Active Tourer). Most use an AGM battery.
Disconnecting
- Switch the car off and remove the key (or keep a keyless fob out of range).
- Open the bonnet and lift the battery cover.
- Loosen the negative (−, black) terminal first and lift the lead clear.
- If removing the battery, loosen the positive (+, red) next, then the hold-down clamp.
Airbag/pretensioner safety: if you’ll be near airbags or seat-belt pretensioners, wait 1 minute after disconnecting.
Reconnecting & Registering
- Reconnect positive (+) first, then negative (−) last; tighten and refit the cover.
- Reset the clock/date (the on-board clock stops while disconnected).
- Register a new battery in the power-management system with BMW diagnostics (dealer or independent with the right software/app) so the car charges it correctly and start/stop keeps working. A simple disconnect/reconnect of the same battery doesn’t need it.
Replace AGM with AGM — don’t fit a standard battery.
Frequently Asked Questions
Where is the 1 Series F40 battery?
In the engine bay — the F40 is front-wheel drive, so (unlike the 3 Series) the battery isn’t in the boot.
Do I have to register a new battery?
Yes — BMW’s charging strategy needs the new battery registered, or it won’t charge it correctly and start/stop may stop working.
Which terminal first?
Disconnect negative (−) first and reconnect it last.
Can I fit a normal (non-AGM) battery?
No — replace AGM with AGM to match the charging strategy and start/stop.
For any warning light that stays on, look up the code on autodtcs.com. To clear the service reminder, see our 1 Series F40 service reset guide.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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