Acura RL. Manual - part 221

lever position signal, to control shifting while the vehicle is ascending or descending a slope.

Fig. 25: Shift Control Diagram - Grade Logic Control
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Grade Logic Control: Ascending Control

When the PCM determines that the vehicle is climbing a hill in D and D3, the system extends the engagement
area of 2nd gear, 3rd gear, and 4th gear to prevent the transmission from frequently shifting between 2nd and
3rd gears, between 3rd and 4th gears, and between 4th and 5th gears, so the vehicle can run smoothly and have
more power when needed.

NOTE:

Shift commands stored in the PCM between 2nd and 3rd gears, between 3rd
and 4th gears, and between 4th and 5th gears, enable the PCM to automatically
select the most suitable gear according to the magnitude of a gradient.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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Fig. 26: Throttle Opening And Vehicle Speed Graph (Grade Logic Control: Ascending Control)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Grade Logic Control: Descending Control

When the PCM determines that the vehicle is going down a hill in D and D3, the shift-up speed from 4th to 5th
gear, 3rd to 4th gear, and from 2nd to 3rd (when the throttle is closed) becomes faster than the set speed for flat
road driving to extend the 4th gear, 3rd gear, and 2nd gear driving areas. This, in combination with engine
braking from the deceleration lock-up, achieves smooth driving when the vehicle is descending. There are three
descending modes with different 4th gear driving areas, 3rd gear driving areas, and 2nd gear driving areas
according to the magnitude of a gradient stored in the PCM. When the vehicle is in 5th or 4th gear and you are
decelerating while applying the brakes on a steep hill, the transmission downshifts to a lower gear. When you
accelerate, the transmission then returns to a higher gear.

Fig. 27: Throttle Opening And Vehicle Speed Graph (Grade Logic Control: Descending Control)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Deceleration Control

When the vehicle goes around a corner and needs to decelerate first and then accelerate, the PCM sets the data
for deceleration control to reduce the number of times the transmission shifts. When the vehicle is decelerating
from speeds above 27 mph (43 km/h), the PCM shifts the transmission from 4th to 3rd earlier than normal to
cope with upcoming acceleration.

Shift-Hold Control

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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When negotiating winding roads, the throttle is suddenly released and the brakes are applied, as is the case
when decelerating at the entrance of a corner, Shift-Hold Control keeps the transmission in its current (lower)
ratio as it negotiates the corner and accelerates out.

When the vehicle is driven aggressively on a winding road, the PCM extends the engagement time of 3rd gear
and 4th gear to prevent the transmission from frequently shifting between 3rd, 4th, and 5th gears. This allows
the driver to have more control for both acceleration and deceleration.

The PCM monitors the average change in vehicle speed and throttle over time. When these values exceed those
for normal driving conditions, the shift-up from 3rd to 4th gear and 4th to 5th gear is delayed. This gives more
control over power, and engine braking when the driver is driving aggressively around winding roads. The
transmission resumes the normal shift-up pattern after the PCM determines that normal driving has resumed.

Fig. 28: Identifying Conventional Automatic Transmission Shift Pattern
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Shift Control - Sequential Sportshift Mode

The RL transmission is provided a sequential sportshift mode in D. In D, the transmission has two shifting
modes; the automatic shift mode and the sequential sportshift mode. In the automatic shift mode used for
general driving, the transmission upshifts and downshifts automatically from 1st through 5th gear. In the
automatic shift mode, the shift indicator and the M indicator in the gauge control module do not come on.

The transmission is switched to the sequential sportshift mode by moving the shift lever into M from D, the
automatic shift mode is canceled, and the sequential sportshift mode comes into operation. The shift indicator
displays the number of the selected gear, and the M indicator comes on. In the sequential sportshift mode, the
driver can shift up and down manually from 1st through 5th gear by using the paddle shifters as well as the shift
lever, much like a manual transmission. The paddle shifters are installed on the back of the steering wheel, and
the driver can shift gears by pulling the paddle shifters without taking either hand off the steering wheel.

In the sequential sportshift mode, the transmission must be shifted up and down by using the shift lever or
paddle shifters. However, the transmission cannot downshift and stays in the current gear if the shift lever is
pulled or the downshift paddle shifter (-, downshift switch) is pulled while the vehicle is coasting at a speed that

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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would cause the engine to over-rev by downshifting the transmission, and the shift indicator blinks the number
of the selected gear several times, then returns to the number of the current gear. If the vehicle speed reaches an
appropriate speed while the shift indicator is blinking the number of the selected gear, the transmission
downshifts and the shift indicator displays the selected gear. The transmission also cannot upshift and stays in
the current gear if the shift lever is pushed or the upshift paddle shifter (+, upshift switch) is pulled while
driving below an appropriate upshifting speed, the shift indicator blinks the number of the selected gear several
times, then returns to the number of the current gear. If the vehicle speed reaches an appropriate upshift speed
while the shift indicator is blinking the number of the selected gear, the transmission upshifts and the shift
indicator displays the selected gear.

When the transmission decelerates to a stop, the transmission shifts to 1st gear automatically. The transmission
can be shifted to 2nd gear by pushing the shift lever or pulling the upshift paddle shifter while the vehicle is
stopped, and the vehicle can start off in 2nd gear.

The sequential sportshift mode is canceled when moving the shift lever to any position other than M.

Fig. 29: Shift Control - Sequential Sportshift Mode
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Clutch Pressure Control

The PCM actuates A/T clutch pressure control solenoid valves A, B, and C to control the clutch pressure. When
shifting between gears, the clutch pressure regulated by A/T clutch pressure control solenoid valves A, B, and C
engages and disengages the clutch smoothly.

The PCM receives input signals from the various sensors and switches, processes data, and outputs the current
to A/T clutch pressure control solenoid valves A, B, and C.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

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