What does 'AC off to protect the engine' mean?

[VonVera]

When a car displays the message 'AC off to protect the engine', it indicates an automatic protection mechanism triggered by starting the vehicle without turning off the air conditioning. During startup, the engine requires a significant instantaneous current, and having the AC on consumes additional current. Simultaneously, the starter motor also bears the extra load from the AC compressor, which can cause substantial damage to the motor. Avoid turning off the engine before switching off the AC. Doing so harms the engine because the next startup will occur with the AC's load, imposing high stress that may damage the engine. Turn off the AC appropriately when necessary. During driving, situations like prolonged traffic jams or waiting may arise. Keeping the AC on while the engine idles for extended periods leads to incomplete fuel combustion, producing high concentrations of carbon monoxide. If surrounding airflow is poor, this exhaust gas may enter the cabin, posing a poisoning risk to occupants. Pointing vents upward cools faster. In summer, directing cool air upward accelerates cabin cooling. Conversely in winter, aiming warm air downward speeds up heating. This principle works because hot air rises, making this method highly fuel-efficient.