BMW 730d Battery Drain — Modules Staying Awake
The E65/E66 has a complex CAN bus network with dozens of control modules. A faulty module that fails to enter sleep mode causes parasitic drain that flattens the battery overnight or over a few days. Common culprits include the TPMS module, comfort access module, telematics unit and DVD changer. Diagnosis requires measuring current draw per CAN bus branch.
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No commonly reported misdiagnoses for this fault yet. If you have replaced a part that did not fix this BMW 7 Series 2002 problem, submit a wrong diagnosis report — it helps other drivers avoid the same costly mistake.
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