2021 BMW 48V Battery Discharge TSB

Symptoms

Owners of affected 2021 BMW vehicles may experience a totally discharged 48V battery. This condition can lead to the need for battery replacement, impacting vehicle operation and potentially incurring repair costs if not covered under warranty or by the manufacturer's guidance.

Diagnosis and Trigger Conditions

BMW has identified several conditions that can lead to a total BMW 48V battery discharge in 2021 models. These include:

• Charging the vehicle using a 12V charger with the hood closed during a prolonged stationary period, such as in a showroom or storage.
• Storing vehicles for an extended period while connected to a low-output solar or trickle charger.
• Storing vehicles for an extended period with no charger connected, resulting in an improperly maintained 12V battery.

These scenarios can prevent the 48V battery from maintaining an adequate charge, ultimately leading to its complete discharge and potential failure.

Important Warnings

To prevent a BMW 48V battery discharge and the potential need for replacement, owners should be aware of specific charging and storage practices to avoid:

• Do not use a 12V charger with the hood closed for extended periods, especially during vehicle storage.
• Avoid relying solely on low-output solar or trickle chargers for long-term vehicle storage, as these may not adequately maintain the 48V battery.
• Ensure proper 12V battery maintenance during extended storage periods, as a poorly maintained 12V battery can indirectly affect the 48V system.

Owner Action

If you own a 2021 BMW 330i, 430i, M340i, 330e, X5, M550i, 540i, X7, M440i, 530e, or 530i and are experiencing issues with your 48V battery, or if your vehicle has been subjected to the conditions described, it is recommended to contact your authorized BMW service center. They can diagnose the battery's condition and advise on the appropriate steps, which may include testing or replacement of the 48V battery.

Source: NHTSA ID: 10202468