Description

CIRCUIT DESCRIPTION
The No. 4 solenoid valve controls the hydraulic pressure acting on the brakes and clutches of the planetary gear units when gears are shifted and does smooth gear shifting.
The Engine Control Module (ECM) determines optimum operating pressure according to the signals from the throttle position sensor, speed sensor and O/D clutch speed sensor and controls the volume of current flow to the solenoid valve.
The amount of electric current to the solenoid is controlled by the (*) duty ratio of ECM output signals, causing momentary change to the hydraulic pressure acting on the clutches during gear shifting. When the duty ratio is high, the hydraulic pressure acting on the clutches is low.
(*) Duty Ratio







The duty ratio is the ratio of the period of continuity in one cycle.
For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then refer to chart above.