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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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OPERATING COMPONENTS AND FUNCTIONS
SensorFunction
Input shaft speed sensor Detect turbine speed at UD retainer
Output shaft speed sensor Detect T/F drive gear speed at T/F driven gear (4A/T)
Crank angle sensor Detect engine speed
TPS(Gasoline) Throttle opening ratio by potentiometer
Air conditioner switch A/C load by thermister
Inhibitor switch Select lever position by contact switch
Brake switch Brake pedal position
Vehicle speed sensor Detect vehicle speed by speedometer driven gear
Sport mode switch Sport mode On/Off signal
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2007 > 2.7L V6 GASOLINE >
Description
The automatic transmission is a combination of 3 - element 2 - phase 1 - stage torque converter and double shaft
electrocally - controlled unit which provides 4 speeds forward and 1 reverse. To improve the efficiency of power
transmission, the line pressure control was changed applying “Variable Force Solenoid (VFS) valve” on this model.
However, adopting VFS on this model, the line pressure is variably changed according to TPS and the vehicle speed,
this will enable more improved efficiency of power transmission and fuel consumption.
Characteristics
Some of the characteristics include:
▶Different power transfer
▶Different component layout
▶New shift logic(HIVEC) to improve shift feeling
▶Position of Valve Body
▶Variable shift pattern
▶Communication protocol and method
▶Step gate type shift lever.
Item Details
Weight Reduction 1. Aluminum oil pump
a. 2.3kg Approx
2. Pressed parts a. Retainer and hub of brakes and clutches
b. Carrier of planetary gear set
Better shift quality 1. Independent control of clutches and brakes enabled better control of
hydraulic pressure and skiped shifts (4 to 2, 3 to 1)
2. During N to D or N to R shift, feedback control adopted.
3. When starting from Creep condition, reduction of shock.(Creep condition is
controlled with 1st gear)
4. Solenoid valve frequency is increased for more accurate control. 35Hz to
61.3Hz except DCCSV that is 35Hz and VFS that is 600Hz.
5. HIVEC adoption for better shift feeling.
6. Variable shift pattern.
Increase in Power train efficiency 1. Fully Variable Line Pressure
2. VFS(Variable Force Solenoid)
- Manual shifting possible
- Step gate type shift lever
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Low&Reverse brakeLRHold LR annulus gear and OD carrier
Second brake 2NDHold reverse sun gear
One way clutch OWCRestrict the rotating direction of low & reverse annulus gear
Operating elements
UD/COD/CREV/C 2ND/B LR/BOWC
P ●
R ●●
N ●
D1 ● ●○
D2 ● ●
D3 ●●
D4 ●●
1) ○ : OWC is operated when shifts from 1st gear to 2nd gear.
2) L&R brake is released in 1st gear when the vehicle speed is more than 5KPH approximately.
Torque converter and shaft
The torque converter consists of an impeller(pump), turbine and stator assembly in a single unit. The pump is
connected to the engine crankshaft and turns as the engine turns. This drawing force is transmitted to the turbine
through the oil which is recycled by the stator.
The transmission has two parallel shafts ; the input shaft and the output shaft. Both shafts are in line with the engine
crankshaft. The input shaft includes the overdrive clutch, reverse clutch, underdrive clutch, one way clutch, 2ND brake,
low&reverse brake, overdrive planetary carrier, output planetary carrier and transfer drive gear. The output shaft
includes the transfer driven gear.
CLUTCHES
The gear changing mechanism utilizes three multi- disc clutches. The retainers of these clutches are fabricated from
high- precision sheet metal for lightness and ease of production. Also, more responsive gearshifts at high engine
speeds are achieved by a pressure- balanced piston mechanism that cancels out centrifugal hydraulic pressure. This
mechanism replaces the conventional ball check valve.
UNDERDRIVE CLUTCH
The underdrive clutch operates in 1st, 2nd, and 3rd gears and transmits driving force from the input shaft to the
underdrive sun gear(A).
The components comprising the under clutch are as illustrated below.
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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.