Acura 3.5 RL Manual page 486

Description
Electronic Control System (cont'd)
Ascending Control
When the PCM determines that the vehicle is climbing a hill in
3rd gear to prevent the transmission from frequently shifting between 3rd and 4th gears, so the vehicle can run smooth
and have more power when needed.
NOTE:
• Shift schedules between 3rd and 4th gear stored in the PCM 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.
Descending Control
When the PCM determines that the vehicle is going down a hill in
when the throttle 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 accelerate, the transmission will
then return to 4th gear.
ASCENDING MODE
3RD/4TH SHIFTING
CHARACTERISTICS
CONTROL AREA
position, the system extends the engagement area of
position, the shift-up speed from 3rd to 4th gear
DESCENDING MODE
Flat road
mode
Steep descending
mode
Gradual descending
mode