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HOLD Function: Drive-Off Assistant, Standstill Management

The HOLD function, considered assistance function, supports the driver when stopping the vehicle and driving off on steep gradients.

The vehicle is automatically secured against rolling backwards.

When the HOLD function is active, the light indicator on the instrument panel comes on.

When adaptive cruise control is operating normally, the HOLD function actively holds the vehicle at a standstill following automatic braking. If the driver's seat belt is unfastened and the driver's door is opened when the HOLD function is active, the electric parking brake is activated automatically.

Information
If the electric parking brake is used to hold the vehicle on the gradient, you can drive off in the usual way.

The electric parking brake detects the start request and is automatically released.

1. Please see chapter "Electric parking brake" on page 73.

Information
The Drive-Off Assistant will not function:

1. In PDK selector-lever position P and N: If the PDK selector lever is moved when the HOLD function is active, the HOLD function is deactivated.
2. If the vehicle is not stationary.
3. If the engine is not running.
4. On gradients of less than 5%.
5. If the driver’s door is opened and the driver’s seat belt is not fastened.
6. If the pressure on the brake pedal is too low.

Driving off with standstill management

The vehicle is held at a standstill without using the brake and secured to prevent it from rolling Information backwards.

Information
The HOLD function can be activated, regardless of the gradient, by quickly flooring the pressed brake pedal while the vehicle is stationary. This keeps the vehicle at a standstill without the brake pedal having to be pressed continuously. A drive position change to the PDK selector lever position does not deactivate the HOLD function.

Drive-Off Assistant Not Working
If the Drive-Off Assistant is not functioning, the driver cannot be assisted when driving off on hills.

• Hold the vehicle with the footbrake.

Slight rolling back on uphill gradients
If the vehicle comes to a standstill on steep gradients without the driver applying the footbrake, the vehicle can roll back until the HOLD function stops it. In this situation it is possible to reduce the roll-back by applying the footbrake.

• Assist holding of the vehicle by increasing the braking force with the footbrake.

Loss of control of the vehicle
The limits set by the laws of driving physics cannot be overcome with the HOLD function. Despite the HOLD function, responsibility for stopping and starting on gradients lies with the driver.

When stopping and starting on slippery surfaces (e.g., icy or loose substrate) the HOLD function cannot be guaranteed to provide assistance. The vehicle can slip in such cases.

• Always adjust your driving style to the road surface and the vehicle load; use the footbrake if necessary.

If the drive-off assistant is not working, it is no longer possible to assist the driver when driving off on gradients.

• Hold the vehicle with the footbrake.

Information
When the HOLD function is active, the driver may feel a difference in the brake pedal and hydraulic noises may be heard. This behavior is typical of the system. There is no fault.