Contents: Engine off/start ⬇ Cars with manual transmission ⬇ Cars with automatic transmission ⬇ Conditions required for the system…⬇ Manual system on/off ⬇ Activation/deactivation ⬇ Display instructions ⬇
The START-STOP system helps to save fuel and, accordingly, reduce harmful CO ₂ emissions. Each time the ignition is switched on, the function is activated automatically. In the Start-Stop mode, when stopping, the car engine switches off automatically, for example, when stopping at a traffic light. The engine also switches on again automatically. The system only works if the following conditions are met: the driver's door is closed, the driver is wearing a seat belt, the hood is closed, the speed after the last stop was higher than 4 km/h, and a trailer is not connected.
Caution! When the engine is off, the brake and steering boosters do not work. Never let the car roll with the engine off. Before driving through a flooded area, be sure to turn off the START-STOP system. If during the STOP phase in a car with a manual or automatic transmission (selector in position P) if the driver's seat belt is unfastened for more than 30 seconds or the driver's door is opened, the engine will need to be started manually. After starting the engine of a vehicle with a manual transmission manually, the engine will only be automatically switched off after the minimum distance required for the Start-Stop system to operate has been covered. If the selector of a vehicle with an automatic transmission is set to the D/S or N position after reversing, the vehicle must first reach a speed of over 10 km/h to automatically switch off the engine again. Changes in outside temperature may cause a noticeable change in the internal temperature of the battery even after several hours. If the vehicle is parked outside for a long time at sub-zero temperatures or in direct sunlight, the internal temperature of the battery may reach a value within several hours at which the START-STOP system operates normally. When the Climatronic climate control system is operating in automatic mode, the engine may not switch off automatically under certain conditions.
Engine off/start
Instrument cluster display: Engine shutdown (Stop phase)

Cars with manual transmission
Stop the car (if necessary, apply the parking brake). Set the gearshift lever to neutral. Release the clutch pedal. The engine will automatically switch off (Stop phase). The display shows the counter, pictogram
Press the clutch pedal.
The engine will start automatically (sTART phase). The control icon goes out.
Cars with automatic transmission
Stop the car and keep the brake pedal depressed. The engine will automatically switch off. The control icon appears on the display. Release the brake pedal. The engine will automatically start. The control icon goes out.
The engine is switched off in selector positions P, D/S, N, and in Tiptronic mode. In selector position P, the engine remains switched off even after the brake pedal is released. The engine is started when the accelerator pedal is pressed, or when the selector is moved to another drive position and the brake pedal is released. If the selector is moved to position R during the Stop phase, the engine is started again. The system recognizes vehicle movement by a large steering angle or by selecting selector position P (for example, when parking), and the engine does not turn off automatically. When the car is moving at low speed (for example, in a traffic jam or when turning) and after lightly pressing the brake pedal stops, the engine does not automatically turn off. When strongly pressing the brake pedal, the engine automatically turns off,
Conditions required for the system to operate
Instrument cluster display: Engine stop function is currently unavailable

The START-STOP system is very complex. Some processes are difficult to control without special equipment.
The engine does not turn off
Before each Stop phase, the system checks that certain conditions are met. The engine does not switch off, for example, in the following situations: the engine has not yet warmed up to the minimum temperature required for the Start-Stop system to operate; the temperature set for the air conditioning system or heater in the passenger compartment has not yet been reached; the outside temperature is very low or very high; windshield heating is on; intensive windshield defrosting mode is on (Climatronic) or windshield defrost fan with maximum air temperature setting (semi-automatic air conditioning); parking assistant or parking autopilot is activated; low battery; the stationary vehicle is on a steep incline or descent; the engine idle speed is too high. The control icon appears on the display
The engine will start automatically
During the Stop phase, the engine starts without active driver intervention, for example in the following cases: the vehicle is rolling, for example on a slope; the difference between the temperature set for the air conditioning system or heater and the temperature in the passenger compartment is too great; windshield heating is on; intensive windshield defrosting mode is on (Climatronic) or windshield defrost fan with maximum air temperature setting (semi-automatic air conditioning); the brake pedal was pressed several times (brake pressure is low); low battery; the current consumption is too high.
Manual system on/off
Start-stop system control key

Activation/deactivation
Press the key
When the Start-Stop mode is off, the indicator in the key lights up.
Note: If the system is switched off during the Stop phase, the engine is automatically started. When the Eco driving mode is selected with the system switched off, the system is automatically activated.
Display instructions
"M" Start the engine manually! "S" START THE ENGINE MANUALLY.
The driver is prompted if the conditions for automatic engine start are not met during the Stop phase. The engine must be started manually.
"M" Error: Start-stop system. "3" START-STOP ERROR.
There is a malfunction in the Start-Stop system. Contact a service station.
