804081 is a fault stored in your BMW's memory (an ISTA fault code, not a standard OBD-II P-code).
What it means: Drive readiness: implausible bus signal — «production/diagnostic mode, faulty». Most often appears with a weak/discharged battery, after long parking or after diagnostics; frequently self-clears. What to check: battery charge and terminals (>12.4 V with engine off); if it returns after charging — network/module diagnosis needed.
