I have a problem with my 718, when ever I stop at traffic light the engine turn off as normal auto stop start function. But, it won’t start automatically. What could be the issue?

Manual or PDK?
Manual requires clutch depression in neutral to startup.

uto Start/Stop Function

When the vehicle stops, e.g. at a traffic light or in a traffic jam, the engine automatically stops, provided all the requirements for the auto stop function are met. In addition, the engine can also stop automatically when the vehicle stops while moving at walking speed. In this way, the automatic Start/Stop function helps to save fuel. The ignition remains on, even when the engine is stopped automatically. All safety functions continue to operate.

Prerequisites for the auto engine stop

1. Auto Start/Stop function switched on.
2. Luggage compartment lids are closed.
3. Engine, transmission, and air conditioning have reached operating temperature.
4. The vehicle has traveled at least at walking speed since the last auto engine stop.
5. Vehicles with PDK:
   Brake pedal pressed.
   Selector lever in position D, N, or P or manually selected drive position 1 or 2.
6. Vehicles with manual transmission:
   Seat belt fastened and driver’s door closed.
   Gear lever in neutral and clutch pedal released.

Vehicles with manual transmission: engine stop and start

Engine stop

1. Brake the vehicle with the footbrake.
2. Move the gear lever to neutral.
3. Release the clutch pedal.
   The engine stops.

Engine start

1. Seat belt fastened.
2. Driver's door closed.

• Press the clutch pedal.
  You can move off as normal.

Information
In certain situations, the engine is started automatically, e.g., if the vehicle is rolling forward or in order to maintain a comfortable temperature.Vehicles with PDK: engine stop and start

Engine stop

1. Brake the vehicle with the footbrake.
2. Press and hold the footbrake. – or –
   While stationary, move selector lever to P.

Information
The HOLD function can be activated by quickly flooring the pressed brake pedal while the vehicle is stationary. This keeps the vehicle at an engine stop without the brake pedal having to be pressed continuously.

1. Please see chapter "HOLD Function: Drive-off Assistant, Standstill Management" on page 121.

The engine starts automatically when the accelerator pedal is pressed or if the engine needs to be started.Information
If the adaptive cruise control (ACC) is switched on, the engine stops automatically when the vehicle is stationary, if the vehicle ahead also comes to a halt.

The vehicle is held in a stationary position by the HOLD function.Engine start

1. Selector lever in position P, D, N or manually selected gear 1 or 2.

• Release the footbrake (not in selector lever position P).
  – or –
  Press the accelerator pedal.
  – or –
  Move the steering wheel.
  – or –
  Select PDK selector lever position R.
  You can drive off normally.

it’s pdk . It just stall & I need to restart the car again

Plus the auto stop start is off

With sport on or off , with auto stop start on or off it just engine stops and you have to restart the car at stop light & traffic . Even the dealer don’t have a clue.

One time they reprogrammed it and it worked for 3 weeks then it happened again