Ford Fusion: Vehicle Dynamic Suspension / Vehicle Dynamic Suspension - System Operation and Component Description. Description and Operation

System Operation

System Diagram

Network Message Chart

  Module Network Input Messages - VDM

Vehicle Dynamic Suspension

The VDM is connected to the HS-CAN to communicate with the ABS module, the PCM and other modules. With the information received the VDM monitors the heave, roll, pitch, cornering, braking and acceleration of the vehicle. Based on this information the VDM calculates the best action for each valve solenoid.

Once the valve solenoid is energized, the damping increases with the PWM duty cycle. At minimum current the damping is less than when max current is applied. The damper and valve solenoid have been designed so failure leads to a firm ride. The fail-safe level of damping is at a level equivalent to what is produced at higher currents, but it is not the same as the maximum current.

When the VDM is initialized (ignition ON), it carries out a preliminary electrical check of the height sensors, height sensor circuits, valve solenoids and valve solenoid circuits. Any malfunction detected in the system causes the VDM to set a DTC (diagnostic trouble code) and send a message over the HS-CAN2 to the GWM . The GWM then sends a message to the IPC over the HS-CAN3 and the IPC responds by displaying a message in the message center.

Component Description

Height Sensor

The height sensor uses a potentiometer to send a variable amount of voltage back to the VDM. The sensor has 3 circuits, one circuit is for the 5 volt sensor supply, one circuit is for sensor ground and one circuit is for the sensor output.

Valve Solenoid

The VDM uses a PWM output to control the valve solenoid. The solenoid opens or closes the valve depending on the amount of current supplied by the VDM. The higher the current, the more the valve is opened, resulting in a higher level of damping.

Vehicle Dynamics Control Module (VDM)

The VDM monitors all sensor inputs and all HS-CAN messages that relate to the vehicle dynamic suspension and then directly controls the valve solenoids. The VDM sends an individual electrical current to each valve solenoid to control the amount of damping required.

When one of the following components is installed new, disassembled, disconnected or removed the VDM requires calibration.

• VDM
• Suspension height sensor
• Front lower control arm
• Front strut assembly
• Rear lower control arm
• Rear shock

The calibration procedure is required for the system to learn the zero-position of the vehicle which means the vehicle must be on a level surface, must not be moving and cannot contain any passengers or cargo. The calibration procedure is carried out using a diagnostic scan tool. The calibration routine should not be performed with the vehicle raised off the ground or immediately after lowering the vehicle as the suspension will not be in a neutral position. The suspension must be neutralized before performing the calibration routine by driving the vehicle for a short distance such as around a parking lot.