BMW Series: 1, 5, 7 - Complete discharge of the battery | HELLA

If a full discharge of the battery after long periods of disuse is determined in the vehicles listed above, the cause may be a defect in the fuel filter heater.

A contact problem results in the battery continuously energising the fuel filter heater. Long periods of disuse may therefore discharge the battery.

The connections in the engine compartment may also scorch, triggering an engine fire in the worst-case scenario.

The vehicle manufacturer has already addressed the issue and notified owners of affected models. For various reasons, however, it must be assumed that not all vehicles have been checked or modified.