NISSAN LATIO 2011 Service Service Manual

AT-24
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
• *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 contract
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 “pro gressive” 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.
POWER TRANSMISSION
“N” and “P” Positions
• “N” position Power from the input shaft is not transmitted to the output shaft because the clutches do not operate.
• “P” position
Similar to the “N” position, the clutches do not operate. The parking pawl engages with the parking gear to
mechanically hold the output shaft so that the power train is locked.
“11” Position
2nd *1A BAutomatic
shift
3rd *1A *2C C B
*11
⇔ 2 ⇔ 3
⇔ 4
4th C*3C C
2 1st
BB
Automatic
shift
1 ⇔ 2 ⇐ 3
2nd
B
3rd *2C CB
1 1st
BB
Locks (held
stationary)
in 1st speed 1 ⇐ 2 ⇐ 3
2nd
B
3rd *2C CB
Shift posi-
tion R/C
5 H/C
6 F/C
15 O/C
17 Band servo
F/O.C
16 L/O.C
18 L&R/B
19 Lock-
up Remarks
2nd
apply 3rd re-
lease 4th ap-
ply
SAT991I
Revision: May 2010 2011 Versa

A/T CONTROL SYSTEMAT-25
< SERVICE INFORMATION >
DE
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M A
B
AT
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“D
1” and “21” Positions
*: Overrun clutch remains in engaged condition when throttle opening is less than 1/16. •
Forward clutch
• Forward one-way clutch
• Overrun clutch
• Low & reverse brake As overrun clutch engages, rear internal gear is locked by the operation of low and re-
verse 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.
SCIA1816E
• Forward one-way clutch
• Forward clutch
• Low one-way clutch Rear 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 th
rottle 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.
Revision: May 2010 2011 Versa

AT-26
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
“D2”, “22” and “12” Positions
*: Overrun clutch remains in engaged condition when throttle opening is less than 1/16.
SAT377J
•Forward clutch
• Forward one-way
clutch
• Brake band Rear sun gear drives rear planetary carrier and combined front internal gear. Front internal gear now rotates
around front sun gear accompanying front planetary carrier.
As front planetary carrier transfers the power to rear internal gear through forward clutch and forward one-
way clutch, this rotation of rear internal gear increases the speed of rear planetary carrier compared with
that of the 1st speed.
Overrun clutch
engagement conditions D
2: OD OFF (OD OFF indicator lamp is on) and throttle opening is less than specification*
2
2 and 12: Always engaged
Revision: May 2010 2011 Versa

A/T CONTROL SYSTEMAT-27
< SERVICE INFORMATION >
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“D
3”, “23” and “13” Positions
*: Overrun clutch remains in engaged condition when throttle opening is less than 1/16.
SAT378J
•
High clutch
• Forward clutch
• Forward one-way
clutch Input power is transmitted to front planetary carrier through high clutch. And front planetary carrier is con-
nected to rear internal gear by operation of forward clutch and forward one-way clutch.
This rear internal gear rotation and another input (the rear sun gear) accompany rear planetary carrier to
turn at the same speed.
Overrun clutch
engagement conditions D
3: OD OFF (OD OFF indicator lamp is on) and throttle opening is less than specification*
2
3 and 13: Always engaged
Revision: May 2010 2011 Versa

AT-28
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
“D4” (OD) Position
SAT379J
•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 brake At D
4 position, there is no one-way clutch in the power transaxle line and engine brake
can be obtained when decelerating.
Revision: May 2010 2011 Versa

A/T CONTROL SYSTEMAT-29
< SERVICE INFORMATION >
DE
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“R” Position
SAT380J
•
Reverse clutch
• Low & reverse brake Front 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 brake As there is no one-way clutch in the power transaxle line, engine brake can be obtained
when decelerating.
Revision: May 2010
2011 Versa

AT-30
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
TCM Function
INFOID:0000000005928075
The function of the TCM is to:
• Receive input signals sent from various switches and sensors.
• Determine required line pressure, shifting poi nt, 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.
SAT381J
SWITCHES & SENSORS
⇒TCM
⇒ACTUATORS
Transmission range switch
Accelerator pedal position signal
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Input speed sensor
Vehicle speed signal
Overdrive control switch signal
Stop lamp switch signal Shift control
Line pressure control
Lock-up control
Overrun clutch control
Fail-safe control
Self-diagnosis
CONSULT-III communication
line control
Shift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
OD OFF indicator lamp
Revision: May 2010
2011 Versa

A/T CONTROL SYSTEMAT-31
< SERVICE INFORMATION >
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CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000005928076
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-7,
"System Description".
Input/Output Signal of TCMINFOID:0000000005928077
JSDIA1518GB
Control itemLine
pressure control Veh icl e
speed
control Shift
control Lock-up
control Engine
brake
control Fail-safe
function Self-diag-
nostics
function
Input Accelerator pedal position signal
(*5)XXXXX(*3) XX
Output speed sensor X X X X X (*3) X X
Vehicle speed signal (*1) X (*1) X (*1) X (*1) X X
Closed throttle position signal
(*5)(*2) X (*2) X X X(*4) X
Wide open throttle position signal
(*5)(*2) X (*2) X (*4) X
Input speed sensor X XXX X
Engine speed signal XXX X
Transmission range sw itch XXXXX(*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 XX X
Revision: May 2010 2011 Versa

AT-32
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
*1: Output speed 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.
Line Pressure ControlINFOID:0000000005928078
• TCM has various line pressure control char acteristics to match the driving conditions.
• An ON-OFF duty signal is sent to the line pres sure 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
Out-
put Shift solenoid valve A/B
X(*3) X X
Line pressure solenoid X (*3) X X
Torque converter clutch solenoid
valve X(
*3 ) X X
Overrun clutch solenoid valve XX (*3) X X
OD OFF indicator lamp
(*6)XX
Control item
Line
pressure
control Vehicle
speed
control Shift
control Lock-up
control Engine
brake
control Fail-safe
function Self-diag-
nostics
function
SAT003J
SAT004J
Revision: May 2010 2011 Versa

A/T CONTROL SYSTEMAT-33
< SERVICE INFORMATION >
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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.
AT LOW FLUID TEMPERATURE
• A/T fluid viscosity and frictional characteristics of t he clutch facing change with A/T fluid temperature. Clutch
engaging or band-contacting pressure is compensated for, according to A/T fluid temperature, to stabilize
shifting quality.
• The line pressure is reduced below 60 °C (140° F) to prevent shift-
ing shock due to high viscosity of A/T fluid when temperature is
low.
• Line pressure is increased to a maximum irrespective of the throt- tle opening when A/T fluid temperature drops to −10° C (14° F). This
pressure rise is adopted to prevent a delay in clutch and brake
operation due to extreme drop of A/T fluid viscosity at low temper-
ature.
Shift ControlINFOID:0000000005928079
The shift is regulated entirely by electronic cont rol to accommodate vehicle speed and varying engine opera-
tions. This is accomplished by electrical signals trans mitted by the output speed sensor and the ECM (acceler-
ator pedal position sensor). This results in improved acceleration performance and fuel economy.
CONTROL OF SHIFT SOLENOID VALVES A AND B
The TCM activates shift solenoid valves A and B according to sig-
nals from the accelerator pedal position sensor and output speed
sensor to select the optimum gear position on the basis of the shift
schedule memorized in the TCM.
The shift solenoid valve performs simple ON-OFF operation. When
set to “ON”, the drain circuit closes and pilot pressure is applied to
the shift valve.
RELATION BETWEEN SHIFT SOLENOID VALVES A AND B AND GEAR POSITIONS
SCIA4828E
SCIA4829E
SCIA4830E
SAT008J
Revision: May 2010 2011 Versa