Mazda RX-8 2004 Service Highlights page 325

LINE PRESSURE CONTROL OPERATION
• Line pressure switches to high or low pressure in accordance with line pressure switching pre-programmed in
the TCM.
• If the pressure control solenoid valve is
energized, line pressure switches to the low-
pressure side; if the pressure control solenoid
valve is de-energized, line pressure switches to
the high-pressure side.
• Line pressure generated by the oil pump
(discharge pressure) acts on the area marked A
on the pressure control valve. It, however, does
not act if the pressure control valve is turned on
by a signal relayed from the TCM. Thus line
pressure is regulated to match the spring force
acting on the right side of the pressure control
valve. If the pressure control solenoid turns off,
solenoid pressure acts and line pressure is
regulated to match the spring force and solenoid pressure acting on the right side of the pressure control valve.
As a result, line pressure is decreased when the pressure control solenoid valve is on, and increased when it is
off.
• Line pressure, which acts only in D, S, or L range, acts on the area marked B on the pressure control valve.
Thus, the pressure control valve moves in the direction in which oil is drained, and line pressure is decreased
by an amount equal to the surface area marked B.
LINE PRESSURE:
ACTS ONLY IN
D RANGE
End Of Sie
05–13–34
AUTOMATIC TRANSMISSION
LINE PRESSURE
PRESSURE
CONTROL VALVE
B
A
DRAIN
TO CONTROL VALVES
(REGULATED)
OIL
PRESSURE
LOW
PRESSURE
SOLENOID ON
SOLENOID PRESSURE
LOWER PASSAGE
OPENS WHEN
SOLENOID
PRESSURE ACTS
SOLENOID
PRESSURE
X
SPRING
CHU051318901S08
HIGH
PRESSURE
D RANGE
P, N, R POSITION
SOLENOID OFF
CHU0513S053
UPPER PASSAGE
OPENS WHEN
SOLENOID PRESSURE
DOES NOT ACT
PRESSURE
CONTROL
SOLENOID
CHU0513S054