What does it mean when the BYD Song engine accessory function is restricted?
2 Answers
BYD Song engine accessory function restricted is the transmission's protection mode. When the transmission computer detects a transmission fault, it will protect the automatic transmission by locking it in a certain gear to reduce damage. Transmission version: The BYD Song's transmission is domestically produced and independently developed by BYD. The BYD Song is equipped with either a 6-speed manual or a 6-speed dual-clutch transmission, depending on the vehicle configuration. Transmission tuning: The transmission tuning does not prioritize shift speed but ensures smoothness for daily use while delivering very smooth power delivery. After engaging the S gear, there is no significant change in throttle response.
I've driven many hybrid vehicles before, and the "Engine Accessory Function Limited" warning in BYD Song is quite common. It means the system has detected issues with engine-related auxiliary functions such as air conditioning, generator, or battery controller, and automatically restricts their operation to protect the vehicle from further damage. This frequently occurs in hybrid models, with possible causes including software glitches, sensor false alarms, low battery levels, or minor component failures. When encountering this, I immediately pull over to check the dashboard for any other warning lights; sometimes restarting the vehicle helps as it might just be a temporary bug. To prevent such issues, it's recommended to regularly visit authorized service centers for software updates and maintenance, and keep the battery adequately charged without waiting until it's too low. Especially during winter or extreme heat when system loads are high and prone to triggering limitations, avoid pushing the vehicle on long trips if unnecessary—safety always comes first.
