Honda Civic Service Manual page 874

Description
The Continuously Variable Transmission (CVT) is an electronically controlled automatic transmission with drive and driv
en Oullevs, and a steel belt. The CVT provides non stage speeds forward and one reverse. The entire unit is positioned in
l i n e w i t h t h e e n g i n e .
Transmission
Around the outside of the flywheel is a ring gear which meshes with the starter pinion when the engine is being staned.
The transmission has four parallel shafts: the input shaft, the drive pulley shaft. the driven pulley shaft, and the secondary
gear shaft. The input shaft is in line with the engine crankshaft. The drive pulley shaft and the driven pulley shaft consist of
movable and fixed face pulleys. Both pulleys are linked by the steel belt.
The input shaft includes the sun gear. The drive pulley shaft includes the forward clutch which mounts the carrier assem-
bly on the forward clutch drum. The carrier assembly includes the pinion gears which mesh with the sun gear and the ring
gear. The ring gear has a hub-mounted reverse brake disc.
The driven pulley shaft includes the start clutch and the secondary drive gear which is integral with the park gear' The sec-
ondary gear shaft is positioned between the secondary drive gear and the final driven gear. The secondary gear shaft
includes the secondary driven gear which serves to change the rotation direction. because the drive pulley shaft and the
driven oullev shaft rotate the same direction. When certain combinations of planetary gears in the transmission are
engaged by the clutches and the reverse brake, power is transmitted from the drive pulley shaft to the driven pulley shaft
to provide E, E, E, and El.
Electronic Control
'96 - 98 Models:
The electronic control system consists of the Transmission Control Module (TCM), sensors, three linear solenoids, and a
inhibitor solenoid. Shifting is electronically controlled under all conditions'
The TCM is located below the dashboard, behind the kick panel on the driver's side.
'99 - 00 Models:
The electronic control svstem consists of a Powertrain Control Module (PCM), sensors, three linear solenoids and an
inhibitor solenoid. Shifting is electronically controlled under all conditions. A Grade Logic Control System to control shift-
ing in E position while the vehicle is ascending or descending a slope.
The PCM is located below the dashboard, under the kick panel on the passenger's side.
Hydraulic Control
The lower valve body assembly includes the main valve body, the Pressure Low (PL) reguiator valve body, the shift valve
body, the start clutch control valve body, and the secondary valve body. They are positioned on the lower part of the
t r a n s m i s s i o n h o u s i n g .
The main valve body contains the Pressure High (PH) control valve, the lubrication valve, and the pitot regulator valve.
The secondary valve body contains the PH regulator valve, the clutch reducing valve, the start clutch valve accumulator,
and the shift inhibitor valve. The PL regulator valve body contains the PL regulator valve and the PH-PL control valve
which is ioined to the PH,PL control linear solenoid. The inhibitor solenoid valve is bolted on the PL regulator valve body.
The shift valve body contains the shift valve and the shift control valve. which is joined to the shift control linear solenoid.
The start clutch control valve body contains the start clutch control valve, which is joined to the start clutch control linear
solenoid. The linear solenoids and the inhibitor solenoid are controlled by the TCM or PCM. The manual valve body which
contains the manual valve and the reverse inhibitor valve, is bolted on the intermediate housing.
The ATF pump assembly is located on the transmission housing, and is linked with the input shaft by the sprockets and
the sprocket chain. The pulleys and the clutch receive fluid from their respective feed pipes, and the reverse brake receives
fluid from internal hydraulic circuit.
Shift Control Mechanism
Input from various sensors located throughout the vehicle determines which linear solenoid the TCM or PCM will activate.
Activating the shift control linear solenoid changes the shift control valve pressure, causing the shift valve to move. This
pressurizes the drive pulley pressure to the drive pulley and the driven pulley pressure to the driven pulley and changes
their effective pulley ratio. Activating the start clutch control linear solenoid moves the start clutch control valve. The start
clutch control valve uncovers the port, providing pressure to the start clutch to engage it
(cont'd)
1 4 - 1 9 5
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