Crosswind Assist Function - GF42.45-D-0004TSA

Model 907 

with code JA8 (Crosswind Assist) 

Shown on model 907 

Function requirements, general 

• "Circuit 15 ON"
• No undervoltage or overvoltage
• Vehicle speed > 80 km/h
• Straight-ahead driving or slight cornering

Crosswind Assist in general 

The Crosswind Assist function detects wind influences that act on the vehicle and warns the driver by means of a message in the multifunction display of the instrument cluster.

Function sequence for Crosswind Assist 

The ESP® control unit processes the following input signals to determine the vehicle behavior:

• Status "Circuit 15 ON"

  The electronic ignition lock control unit (EZS) control unit sends the status "tml. 15 ON" via the suspension FlexRay.

• Yaw response

  The yaw rate sensor for lateral and longitudinal acceleration, which is integrated in the in the Supplemental Restraint System (SRS) control unit, detects the movement of the vehicle when it encounters strong gusts of wind. The SRS control unit sends the signals to the ESP® control unit via the vehicle dynamics CAN.

  If the ESP® control unit detects track offset caused by strong crosswinds, it brakes the wheels on the side facing the wind, causing the track offset to decrease. The driver does not have to perform large steering movements in order to stay in the lane.

• Vehicle speed

  The ESP® control unit calculates the vehicle speed from the wheel speeds which it reads in directly from the RPM sensors.

• Steering angle

Steering movements are detected by the steering angle sensor.

The steering column tube module (MRM) control unit reads in the signals from the steering angle sensor directly and sends them via the suspension FlexRay.

After processing the signals, the ESP® control unit regulates a one-sided intervention by the brake system on the front and rear axle, thereby generating a yaw motion, which counteracts the crosswind.

Regulation of the one-sided brake intervention is controlled by the ADAPTIVE BRAKE.

Output of warning message 

The warning message "Crosswind Assist intervention" is generated in the multifunction display of the instrument cluster. The ESP® control unit sends the request to actuate the multifunction display via the suspension FlexRay, the EZS control unit and the user interface CAN to the instrument cluster.

Electrical function schematic for Crosswind Assist	PE42.45-D-2053-97TSA
Overview of system components for driver assistance systems	GF54.00-D-9998TSA