Expedition 2WD V8-4.6L SOHC VIN 6 (1999)
Suspension Control Module: Description and Operation
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it
is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension
control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension
control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by
monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the
Brake Pedal Position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and
communication software for testing the vehicle and related components.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control
module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection
to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
