Page 35 of 2896

AT-22
A/T CONTROL SYSTEM
Revision: June 20062007 Versa
CLUTCH AND BAND CHART
*1: Operates when OD OFF. (OD OFF indicator lamp is on.)
*2: Oil pressure is applied to both 2nd “apply” side and 3rd “release” side of band servo piston. However, brake band does not con-
tract because oil pressure area on the “release” side is greater than that on the “apply” side.
*3: Oil pressure is applied to 4th “apply” side on condition *2 above, and brake band contracts.
*4: A/T will not shift to 4th when OD OFF. (OD OFF indicator lamp is on.)
: Operates.
A: Operates when throttle opening is less than specification**, activating engine brake.
B: Operates during “progressive” acceleration.
C: Operates but does not affect power transmission.
D: Operates when throttle opening is less than specification**, but does not affect engine brake.
–**: Overrun clutch remains in engaged condition when throttle opening is less than 1/16. Shift posi-
tionR/C
5H/C
6F/C
15O/C
17Band servo
F/O.C
16L/O.C
18L&R/B
19Lock-
upRemarks
2nd
apply3rd
release4th
apply
PPA R K
POSITION
RREVERSE
POSITION
NNEUTRAL
POSITION
D*4 1st *1D B B
2nd *1A BAutomatic
shift
3rd *1A *2C C B
*11 ⇔ 2 ⇔ 3
⇔ 4
4th C *3C C
21stBB
Automatic
shift
1 ⇔ 2 ⇐ 3 2ndB
3rd *2C C B
11stBB
Locks (held
stationary)
in 1st speed
1 ⇐ 2 ⇐ 3 2ndB
3rd *2C C B
Page 37 of 2896
AT-24
A/T CONTROL SYSTEM
Revision: June 20062007 Versa
“11 ” Position
Forward clutch
Forward one-way clutch
Overrun clutch
Low & reverse brakeAs overrun clutch engages, rear internal gear is locked by the operation of low and
reverse brake.
This is different from that of D
1 and 21 .
Engine brake Overrun clutch always engages, therefore engine brake can be obtained when deceler-
ating.
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Page 38 of 2896
A/T CONTROL SYSTEM
AT-25
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: June 20062007 Versa
“D1 ” and “21 ” Positions
*: Overrun clutch remains in engaged condition when throttle opening is less than 1/16.
Forward one-way clutch
Forward clutch
Low one-way clutchRear internal gear is locked to rotate counterclockwise because of the functioning of these three
clutches.
Overrun clutch
engagement conditions
(Engine brake)D
1 : OD OFF (OD OFF indicator lamp is on) and throttle opening is less than specification*
2
1 : Always engaged
At D
1 and 21 positions, engine brake is not activated due to free turning of low one- way clutch.
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Page 41 of 2896
AT-28
A/T CONTROL SYSTEM
Revision: June 20062007 Versa
“D4 ” (OD) Position
High clutch
Brake band
Forward clutch (Does not affect power
transmission)Input power is transmitted to front carrier through high clutch.
This front carrier turns around the sun gear which is fixed by brake band and makes
front internal gear (output) turn faster.
Engine brakeAt D
4 position, there is no one-way clutch in the power transaxle line and engine
brake can be obtained when decelerating.
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Page 42 of 2896
A/T CONTROL SYSTEM
AT-29
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: June 20062007 Versa
“R” Position
Reverse clutch
Low & reverse brakeFront planetary carrier is stationary because of the operation of low and reverse brake.
Input power is transmitted to front sun gear through reverse clutch, which drives front
internal gear in the opposite direction.
Engine brakeAs there is no one-way clutch in the power transaxle line, engine brake can be
obtained when decelerating.
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Page 43 of 2896

AT-30
A/T CONTROL SYSTEM
Revision: June 20062007 Versa
TCM FunctionUCS005MC
The function of the TCM is to:
Receive input signals sent from various switches and sensors.
Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transaxle senses vehicle operating conditions through various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM DIAGRAM
SWITCHES & SENSORS
TCM
ACTUATORS
PNP switch
Accelerator pedal position signal
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Turbine revolution sensor (Power
train revolution sensor)
Vehicle speed sensor
Overdrive control switch signal
Stop lamp switch signalShift control
Line pressure control
Lock-up control
Overrun clutch control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
controlShift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
OD OFF indicator lamp
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Page 44 of 2896

A/T CONTROL SYSTEM
AT-31
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: June 20062007 Versa
CAN CommunicationUCS005M D
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-47,
"CAN System Specification Chart" .
Input/Output Signal of TCMUCS005M E
*1: Spare for vehicle speed sensor·A/T (revolution sensor)
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: Used as a condition for starting self-diagnostics; if self-diagnosis are not started, it is judged that there is some kind of error.
*5: Input by CAN communications.
*6: Output by CAN communications.Control itemLine
pressure
controlVehicle
speed
controlShift
controlLock-up
controlEngine
brake
controlFail-safe
functionSelf-diag-
nostics
function
InputAccelerator pedal position signal
(*5)XXXXX(*3) XX
Vehicle speed sensor·A/T
(Revolution sensor)XXXXX(*3) XX
Vehicle speed sensor·MTR (*1) X (*1) X (*1) X (*1) X X
Closed throttle position signal
(*5)(*2) X(*2) XXX(*4) X
Wide open throttle position signal
(*5)(*2) X (*2) X (*4) X
Turbine revolution sensor (Power
train revolution sensor)XX X XX
Engine speed signal X X X X
PNP switch X X X X X (*3) X (*4) X
Stop lamp switch signal
(*5)XX (*4) X
A/T fluid temperature sensors
(*5)XXXX XX
Overdrive control switch signal
(*5)XXXX (*4) X
TCM power supply voltage signal X X X X
Out-
putShift solenoid valve A/B X (*3) X X
Line pressure solenoid X (*3) X X
Torque converter clutch solenoid
valveX(*3) XX
Overrun clutch solenoid valve X X (*3) X X
OD OFF indicator lamp
(*6)XX
Page 45 of 2896

AT-32
A/T CONTROL SYSTEM
Revision: June 20062007 Versa
Line Pressure ControlUCS005M F
TCM has various line pressure control characteristics to match the driving conditions.
An ON-OFF duty signal is sent to the line pressure solenoid valve based on TCM characteristics.
Hydraulic pressure on the clutch and brake is electronically controlled through the line pressure solenoid
valve to accommodate engine torque. This results in smooth shift operation.
NORMAL CONTROL
The characteristic of the line pressure to the throttle opening is set
for suitable clutch operation.
BACK-UP CONTROL (ENGINE BRAKE)
If the selector lever is shifted to “2” position while driving in D4 or D3,
great driving force is applied to the clutch inside the transaxle. Clutch
operating pressure (line pressure) must be increased to deal with
this driving force.
DURING SHIFT CHANGE
The line pressure is temporarily reduced corresponding to a change
in engine torque when shifting gears (that is, when the shift solenoid
valve is switched for clutch operation) to reduce shifting shock.
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