Hill Start Assist, Basic Function - GF42.47-P-1010A

Model All (4xWD, CAR) 

Overview 

This document contains information on:

• General 
• Function requirements 
• Function 
  • Releasing Hill Start Assist 
  • Canceling Hill Start Assist 

General 

Hill Start Assist prevents the vehicle from rolling back when starting off on a hill.

The function is automatically triggered when, during vehicle stillstand, an incline or slope is detected that would cause the vehicle to roll contrary to the drive range engaged.

Function requirements 

• Drive train operational
• Transmission is in position D or R
• Electric parking brake is released

Function 

Releasing Hill Start Assist 

If the brake pedal is released and it is detected that the vehicle is starting off, brake pressure is reduced. To this end, the slope output torque is compared with the available start-off torque.

If the start-off torque is sufficiently large, Hill Start Assist is deactivated and the vehicle starts off without rolling in the undesired direction of travel.

If the driver does not operate the brake pedal, the pressure in the brake system is reduced after 1 s.

Canceling Hill Start Assist 

The Hill-Start Assist is terminated immediately if

• The engine is switched off. (Exception: The engine is switched off by the ECO start/stop function)
• The driver terminates the pulling away procedure by fully releasing the accelerator pedal.
• A forward/reverse gear drive range change takes place.
• A drive range change to selector lever position "N" takes place.
• The electric parking brake is actuated.
• The vehicle is slipping.

The Hill-Start Assist does not function, if

• The vehicle is driven off on a level road or on a downhill gradient.
• The transmission is in selector lever position "N".
• The electronic parking brake is applied.
• The ESP® is malfunctioning.
• The vehicle is slipping.

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