VW T6.1 SOS battery see workshop warning fix

The Problem

The VW T6.1 displayed a persistent "SOS battery: see workshop" warning on every ignition cycle despite live data showing the backup battery at 90% state of health. Standard fault code clearing did not resolve it because the codes returned instantly, indicating the fault was software-triggered rather than a genuine hardware failure.

Solution

1. With the ignition on and engine off, connect OBDeleven to the OBD2 port and open the app.

   • A Pro plan is required to access the Basic Settings function used in this fix.

2. Tap the vehicle icon at the bottom of the app to access control units — this is not available from the home page.

3. Enter Control Unit 75 (Telematics).

4. Use the search bar within the module and type "Battery" to find "Backup_Battery-SoH" under live data, then check the state of health reading.

   • If the value is good (e.g. 90%), the fault is software-triggered and this reset procedure is appropriate; a genuinely degraded battery will need replacement instead.

5. Navigate to Basic Settings within the Telematics module.

6. Select and run "Resetting the history of the emergency call battery" — this resets the battery memory so the module recognises the battery as new.

7. After the Basic Settings procedure completes, run a standard fault code clear.

8. Confirm the SOS warning has cleared and does not return on the next ignition cycle.

   • If the warning does not reappear, the fix is confirmed. If it returns, the physical battery may genuinely need replacement.

9. If you already have VCDS, the same Basic Settings reset can be performed there as an alternative to OBDeleven.

   • Carista cannot perform this specific reset even if the fault code is visible, so it is not a viable substitute.