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How to Replace the SOS Module Battery on a Citroen/Peugeot/Opel

Model: Citroen C3 Aircross - Years: 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024
Part: Checks and maintenance

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Video tutorial

On Citroën, Peugeot, and Opel models from the Stellantis group, the flashing red light on the SOS button indicates that the backup battery of the telematics module (TCU/BTA) is flat and needs replacing. The module's location varies: on C3 Aircross and 2008, it is behind the touchscreen/radio, above the centre console; on other models, it may be in the engine bay or footwell.

The procedure shown in the video (dismantling the screen, extracting the module, opening, rebuilding the battery pack, reassembling, testing) is logically correct. The critical point: the battery is not available as a single replacement at reasonable prices (it costs about £180 at the dealership), but it can be rebuilt.

Simply purchase two CR123A 3V batteries (about £8.50 in total) and connect them in series to achieve the necessary 6V, soldering the original connector to the new pair. Some users recommend using a pre-packaged battery (thicker but functional) to avoid soldering.

After replacement, no programming is required: the light will stop flashing on its own. The battery is a safety component (eCall); if you are not comfortable soldering, it is better to consult a workshop.


Posted on 14 November 2026 by ScegliAuto


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