Honda Civic Service Manual page 695

Description
Electronic Control System {cont'dl
Ascending Control
When the PCM determines that the vehicle is climbing a hill in E position, the system oxtends the sngagement area of
2nd gear and 3rd gear to prevent ths transmission from fr€quently shifting between 2nd and 3rd gears, and between 3rd
and 4th gears, so the vehicle can run smooth and have more power when needed. There are two ascending modes with
different 3rd gear driving areas according to the magnitude of a gradient stored in the pCM.
NOTE:
. The PCM memory contains shift schedules between 2nd and 3rd gears, and between 3rd and 4th gears that enable the
PCM's fuzzy logic to automatically select the most suitable gear according to the magnitude of a gradient
. Fuzzy logic is a form of artificial intelligence that lets computers respond to changing conditions much like a human
mind would,
Dssconding Control
When the PCM determines that the vehicle is going down a hilt in E position, the shift-up speed from 3rd to 4th gear
when th€ throftle is closed becomes faster than the set speed for flat road driving to widen the 3rd gear driving area.
This, in combination with engine braking from the deceleration lock-up, achieves smooth driving when the vehicle is
descending. There are two descending modes with different downshift (4 - 3) schedules according to the magnitude of a
gradient stored in the PCM. When the vehicle is in 4th gear, and you are decelerating on a gradual hill, or when you are
applying the brakes on a steep hill, the transmission will downshift to 3rd gear. When you accel6rate, the transmission will
then return to 4th gear.
ASCENDING MODE
DESCENDING MODE
4TH SHIFTING
L .
F
CHARACTERISIICS
CONTROL AREA
ff.1"11", vehicr. 3pe€d
ff;Tlr.,
vohicre speed
GRADUAL ASCENOING
CONTROL AREA
Docel6ration Control
When the vehicle goes around a corner. and needs to first decelerate and then accelerate. the rcM sets the data for deceleration
control to reduce the number of times the transmission shifts. When the vehicle is decelerating from speeds above 26 mph
(41 km/h), the rcM shifts the transmission from 4th to 2nd earlier than normal to cope with upcoming acceleration.
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