BMW 328i check engine light issue following alternator replacement on BMW 328i

Some BMW 328i owners report experiencing a check engine light issue following an alternator replacement, which may stem from various factors such as sensor failures, catalytic converter problems, or a loose gas cap. These owners emphasize the importance of diagnosing the issue using an OBD-II scanner to determine the cause and severity of the problem. Common causes identified include emissions faults, sensor issues, and the need for oxygen sensor replacements. If the check engine light remains illuminated after tightening or replacing the gas cap, further evaluation by a qualified mechanic is recommended, as it could indicate underlying electrical problems like a failing battery or alternator. Additionally, some owners note that a flashing check engine light signifies a more urgent issue that requires immediate attention to prevent significant damage to the vehicle.