What does AOFF mean in cars?
4 Answers
In cars, AOFF refers to the automatic start-stop switch. The engine automatic start-stop system automatically shuts off the engine when the vehicle comes to a temporary stop during driving and restarts it when needed to continue moving. The features of the automatic start-stop function include: 1. The engine can automatically shut off, reducing fuel consumption and emissions; 2. After the engine shuts off, the power supply can replace the belt pulley to provide operating power for the engine cooling fan and the car's air conditioning. Precautions for using the automatic start-stop system are: 1. Quickly shift to P gear when the engine stops and release the brake; 2. Reduce current consumption; 3. Do not repeatedly press the brake when the engine is off; 4. Let the engine speed drop to zero, engage the starter gear, and then restart; 5. Do not activate the automatic start-stop system during low-speed parking or when the air conditioning is on.
I just heard about this AOFF indicator from a technician at the 4S store a couple of days ago. It actually indicates that the auto start-stop function is turned off. When I was driving my friend's new car last time, the engine kept stopping and suddenly restarting at every red light, which made me super nervous. So I directly pressed a button with a circular arrow on the center console, and the AOFF popped up on the dashboard. The technician said turning it off can extend the battery life, especially in northern winters where temperatures drop below minus ten degrees Celsius, as the battery is more prone to draining. However, environmentalists might not like this, since the auto start-stop can indeed save about 8% of fuel.
Last time when I was stuck at an intersection picking up my child from school, I noticed a yellow AOFF light suddenly appeared on the dashboard. After consulting a mechanic, I learned this indicates the system detected insufficient battery voltage and automatically disabled the start-stop function. My car's battery hadn't been replaced in four years. The mechanic tested it with a battery analyzer and confirmed it only had 35% lifespan remaining. This reminds everyone: if you see this warning, it's best to check your battery promptly, especially for vehicles with automatic start-stop systems that use AGM batteries - replacing one can cost nearly 2,000 yuan. By the way, the system also automatically disables start-stop when wading through water in rainy conditions, which is a protective design for the engine.
I always turn off the auto start-stop function as soon as I get in the car. Once, before driving on the highway, I checked the car's condition and found a small button on the lower left side of the steering wheel with an icon of the letter A and a circular arrow. After pressing it, the dashboard displayed 'AOFF,' and the airflow from the AC became noticeably more stable—previously, every time the start-stop function activated, the AC compressor would shut off for a few seconds, making my back sweat. The mechanic said frequent starts do cause wear on the engine, especially in older cars where piston clearances have increased. Nowadays, new hybrid electric vehicles are smarter, using the motor to power the AC, so this issue doesn't occur during start-stop.
