1996 Legacy Wagon 4WD F4-25L DOHC: Cruise Control Vacuum Pump Description
Vacuum Pump: Description and Operation
VACUUM PUMP AND VALVE
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The vacuum pump activates when signal is emitted (current supply is ON) from cruise control module to supply the vacuum pressure to the cruise
control system.
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The air valve shuts off the atmospheric pressure while the current supply is ON and retains the vacuum pressure in the actuator vacuum pressure
chamber. When the current supply is interrupted, this valve opens and introduces the atmospheric pressure to the actuator chamber.
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The release valve blocks the atmospheric pressure while the current supply is ON, and introduces the atmospheric pressure when the current
supply is OFF.
When cruise control is canceled, the air valve is opened simultaneously to introduce the atmospheric pressure for faster deceleration.
When the cruise control is out of operation, the air valve and release valve are opened and the vacuum pump is not activated. Therefore, the inside
of the actuator is at atmospheric pressure, and the diaphragm does not operate.
During constant-speed driving with the cruise main switch ON, the air valve and vacuum pump are activated or not activated alternately while the
release valve is closed in order to introduce a vacuum pressure or atmospheric pressure into the actuator.
In this condition, move the diaphragm, which operates the throttle cam to provide control over the vehicle speed.
How the vacuum pump and valves operate in response to signals from the cruise control module.