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2007 > 2.7L V6 GASOLINE >
Electronic Control System
DESCRIPTION
The electronic control system used in the new generation auto transaxle is far superior to the previous systems. This
system is able to adopt a variable shift pattern for smooth and problem free shifting.
A solenoid valve is applied to each of the clutches and brakes and is independently controlled. Feedback control and
correction control is performed in all gears as well as utilization of mutual control system to increase shift feeling.
The torque converter damper clutch uses a partial lock up and full lock - up system. An additional control method called
the HIVEC system (neural network) is adopted to increase shift feeling.
Block Diagram (CAN)
ELECTRIC CONTROL LOCATION
The TCM(PCM) is located on the intake manifold in the engine room.
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B42OD Solenoid Pulse
Vpeak : Max. 70V 56.3V
W/H Open DTC Spec : P0765DTC : P0765
B43 DCC solenoid Lock_Up on
PulseHI : V_BAT
LO : Max. 1.0V
Vpeak : Max. 70V 15.4V
0.45V
56.3V
W/H Open DTC Spec : P0743DTC : P0743
B44 RED Solenoid Shifting
Pulse HI : V_BAT
LO : Max. 1.0V
Vpeak : Max. 70V 15.4V
0.45V
56.3V
W/H Open DTC Spec : P0770DTC : P0770
B45 2ND Solenoid Shifting
Pulse HI : V_BAT
LO : Max. 1.0V
Vpeak : Max. 70V 15.4V
0.45V
56.3V
W/H Open DTC Spec : P0760DTC : P0760
B46 N.A -- - -
B47 N.A -- - -
B59 Variable Solenoid ( - ) Idle
Pulse HI : V_BAT
LO : Max. 1.0V
Vpeak : Max. 70V 1.8/1.2V - N
range
0.03V(DC) - D range 600Hz
W/H Open DTC Spec : P0748DTC : P0748
B65 N.A -- - -
B66 N.A -- - -
B75 Variable Solenoid (+) Idle
Pulse HI : V_BAT
LO : Max. 1.0V
Vpeak : Max. 70V 13.1V
- 0.07V
W/H Open DTC Spec : P0748DTC : P0748
B80 N.A -- - -
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fluctuated even though turns on or off the input signal. The electrical ‘time constant’ is much more fast than one of
mechanical so the frequency of VFS is extremely higher than the conventional PWM type.
Characteristics of Bosch VFS:
Supply pressure : 700~1600kPa
Control pressure: typically 600~0 kPa
Current range: typically 0~1,000 mA
Dither frequency: Up to 600 Hz
Dimension: 32 mm protrusion reach 42 mm
The reducing pressure will be supplied to the ‘Supply’ port of the VFS valve on the above illustration to control the line
pressure.
Reducing pressure
Function
As same as one of Alpha or Beta automatic transaxle system, this reducing valve length can be adjusted by rotating
the screw on the picture. As you rotate the screw toward clockwise by 90°, the reducing pressure will increase about
1.0bar. However, the reducing pressure is used just as a ‘supply pressure’ for the solenoid valves (except
Low&Reverse, Reduction and Damper Clutch control solen), so this may not be handled to rotate in the field service
shop. VFS is operated based on the ‘supply pressure’ and it outputs the ‘control pressure’ to control the regulator
valve indirectly. While developing the VFS system, the line pressure was used as a ‘supply pressure’ for VFS and
other solenoid valves but it has been changed into additional ‘reducing pressure’ because the line pressure is variably
changed by VFS so the control pressure becomes unstable and some hydraulic pressure oscillation occurred. That is
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BRAKES
The gear changing mechanism utilizes two multi- disc brakes.
LOW&REVERSE BRAKE AND SECOND BRAKE
The low&reverse brake(A) operates in 1st and reverse gears, when the vehicle is parked, and during manual
operation. It locks the low&reverse annulus gear and overdrive planetary carrier to the case.
The second(C) brake(B) operates in 2nd and 4th gears and locks the reverse sun gear(D) to the case.
The components comprising the low&reverse brake and second brake are as illustrated below.
As shown, the discs and plates of the two brakes are arranged on either side of the rear cushion plate(E), which is
itself secured to the case(F) by a snap ring.
OWC
To improve the shift feeling from 1st to 2nd gear, OWC was adopted on the low&reverse brake annulus gear. Instead
of hydraulic fixing by Low&reverse brake at the 1st gear, this mechanical fixing device was used. This structure is not
a new concept, because this OWC already has been installed on the previous models.
ACCUMULATORS
NumberFunction Name Color
1 Low&Reverse Brake None
2 Underdrive Clutch Yellow
3 Second Brake Blue
4 Overdrive Clutch None
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Objective
* Energy (hydraulic pressure) storage
* Impact and pulsation damping when solenoid valves operating
* Operation as spring element
* Smooth shifting by preventing sudden operation of clutches and brakes
TRANSFER DRIVE GEAR
With the transfer drive gear, increased tooth height and a higher contact ratio have reduced gear noise.
Also, the bearing that supports the drive gear is a preloaded type that eliminates rattle, and the rigidity of the gear
mounting has been increased by bolting the bearing directly onto the case.
OUTPUT SHAFT/TRANSFER DRIVEN GEAR
As shown in the illustration below, the transfer driven gear is press- fitted onto the output shaft, and the output shaft is
secured by a locking nut and supported by bearings.
The locking nut has a left- handed thread, and a hexagonal hole in the other end of the shaft enables the shaft to be
held in position for locking nut removal.
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MANUAL CONTROL SYSTEM
MANUAL CONTROL LEVER
The manual control lever is fitted to the top of the valve body and is linked to the parking roller rod and manual control
valve pin.
A detent mechanism is provided to improve the gear shift feeling during manual selection.
PARKING MECHANISM
When the manual control lever is moved to the parking position, the parking roller rod moves along the parking roller
support and pushes up the parking sprag.
As a result, the parking sprag meshes with the transfer driven gear (parking gear), thereby locking the output shaft. To
minimize the operating force required, a roller is fitted to the end of the rod.
POWER TRAIN
P POSITION
Hydraulic pressure is applied to the LR brake and the RED brake, so power is not transmitted from the input shaft to
the UD clutch or OD clutch, and the output shaft is locked by the park brake pawl interlocking the park gear.
N POSITION
Hydraulic pressure is applied to the LR brake(A) and the RED brake, so power is not transmitted from the input shaft
to the UD clutch or OD clutch.
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1st GEAR POWER FLOW
Hydraulic pressure is applied to the UD clutch(B) the LR brake(A) and the one way clutch(OWC), then the UD clutch
transmits driving force from the input shaft to the UD sun gear, and the LR brake locks the LR annulus gear to the
case.The UD sun gear of the planetary gear drives the output pinion gear, and the LR brake locks the annulus gear,
and the output pinion drives the output carriers, and the output carrier drives the transfer drive gear, and the transfer
drive gear drives the transfer driven gear of the output shaft, and power is transmitted to the differential gear through
the differential drive gear.
2nd GEAR POWER FLOW
Hydraulic pressure is applied to the UD clutch(A) the 2nd brake(B) and the one way clutch(OWC), then the UD clutch
transmits driving force from the input shaft to the UD sun gear, and the 2nd brake locks the reverse sun gear to the
case.The UD sun gear of the planetary gear drives the output pinion gear and the LR annulus gear, and the LR
annulus gear drives the OD planetary carriers, and OD planetary carriers drives OD pinion gear, and the OD pinion
gear drives the output carriers, and the output carrier drives the transfer drive gear, and the transfer drive gear drives
the transfer driven gear of the output shaft, and power is transmitted to the differential gear through the differential
drive gear.
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3rd GEAR POWER FLOW
Hydraulic pressure is applied to the UD clutch(A) and the OD clutch(B), then the UD clutch transmits driving force from
the input shaft to the UD sun gear, and the OD clutch transmits driving force from the input shaft to the overdrive
planetary carrier and low&reverse annulus gear.The UD sun gear of the planetary gear drives the output pinion gear
and the LR annulus gear, and the LR annulus gear drives the OD pinion gear through the OD planetary carrier, and
the OD pinion gear drives the reverse sun gear and the output carrier.The OD clutch drives the OD carrier, and the
OD carrier drives the OD pinion gear, and the OD pinion gear drives the reverse sun gear and the output carrier, and
the output carrier drives the transfer drive gear, and the transfer drive gear drives the transfer driven gear of the
output shaft, and power is transmitted to the differential gear through the differential drive gear.
4th GEAR POWER FLOW
Hydraulic pressure is applied to the OD clutch(A) and the 2nd brake(B), then the OD clutch transmits driving force
from the input shaft to the OD planetary carrier and LR annulus gear, and the 2nd brake locks the reverse sun gear to
the case.The OD clutch drives the OD carrier, and the OD carrier drives the OD pinion gear and the LR annulus gear,
and the OD pinion gear drives the output carrier, and the output carrier drives the transfer drive gear, and the transfer
drive gear drives the transfer driven gear of the output shaft, and power is transmitted to the differential gear through
the differential drive gear.