Lincoln Aviator: Vehicle Dynamic Suspension / Description and Operation - Vehicle Dynamic Suspension - Vehicles With: Air Suspension - System Operation and Component Description

System Operation

System Diagram

Network Message Chart

  Module Network Input Messages - SUMA

Air Suspension

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

When the SUMA is initialized (ignition on), it carries out a preliminary electrical check of the height sensors, height sensor circuits, solenoids and solenoid circuits. Any malfunction detected in the system causes the Air Suspension Control Module 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

Easy Entry/Exit Feature

When the vehicle is in Standard operating condition (not in the Deep Conditions or Excite selectable drive mode the vehicle will lower (0.6 inches) 15mm upon igition off. This will be interrupted if a door is opened during the leveling process and will resume once the door is closed. The vehicle then will kneel an additional ( 1 inch) 35mm for a total of a ( 2 inch) 50mm drop upon the customers approach. Approach is detected by Key Fob proximity, pressing the unlock button on the Fob, or remote start. Again, this will be interrupted if a door is opened during the leveling process, however it will not resume once the door is closed. The vehicle is intended to only level the front or rear of the vehicle at a time.

Height Sensor

The height sensor sends a PWM signal back to the SUMA. 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.

Air Spring Solenoid

The SUMA uses a PWM output to control the air spring solenoid. The solenoid opens or closes depending on the amount of current supplied by the SUMA.

Air Suspension Compressor Assembly

The Air Suspension Compressor Assembly is a 4 channel system, it supplies and controls air pressure to the the front and rear air springs independently. This is a closed system with an air pressure reservoir.

The compressor only maintains system pressure and can not inflate the entire system if pressure is fully discharged.

SUMA (Suspension Control Module A)

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

The SUMA is integral to the Air Suspension Compressor and not replaceable separately.

The SUMA requires calibration when one of the following components is installed new, disassembled, disconnected or removed.

• SUMA
• Suspension height sensor
• Front air spring
• Rear air spring

The calibration procedure is carried out using the diagnostic scan tool and is required for the system to learn the zero-position of the vehicle.

Before performing the calibration procedure:

• Be sure the vehicle is on a level surface.
• The vehicle must not be moving.
• No occupants in the vehicle.

Make sure the suspension is in a neutral position if it was recently lowered. To neutralize the suspension, drive the vehicle a short distance, such as around a parking lot.