Expedition 4WD V8-281 4.6L SOHC (1998)
Level Control Solenoid Valve: Description and Operation
Inflator Solenoid, Level Control
Front Fill Solenoid
The front fill solenoid connects the output of the compressor assembly to the two front air shocks. When energized along with the front gate solenoid, air
pressure to the front axle can be modified, affecting its height relative to the body.
Front Gate Solenoid
The front gate solenoid provides pneumatic isolation of the left and right sides of the vehicle. The separation is necessary to eliminate the transfer of air
from left to right front air shocks during roll conditions. When the solenoids are off (closed) the left and right air shocks are separated, allowing a
pressure differential to be generated. In a turn, the increased pressure in the two outermost air shocks raises the two outer wheel spring rates, decreasing
vehicle roll.
Conversely, opening (energizing) the gate solenoid on smooth driving surfaces connects the left and right air shocks. This forces left and right side air
pressures to be the same. Also, allowing the transfer of air reduces the resistance to vertical wheel movement, resulting in a softer ride.
Rear Fill Solenoid
The rear fill solenoid connects the output of the compressor assembly to the two rear air shocks. When energized along with the two integrated rear
solenoids, air pressure to the rear axle can be modified, affecting its height relative to the body.
