A lamp-failure warning can indicate that an exterior lighting function is not operating as expected. It may concern a lamp you cannot see from the driver's seat, such as a brake light or rear signal.
With the vehicle safely parked, check the affected lighting functions and ask someone to help observe the rear lamps when practical. A bulb is one possible cause, but wiring, connectors, or lamp electronics can also be involved.
Tell Cherry City Transmissions which light is affected and whether the message followed a bulb replacement or other work. Do not assume that a working dashboard indicator proves the exterior lamp is operating.