NISSAN LATIO 2008 Service Owner's Guide

A/T CONTROL SYSTEM
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A/T CONTROL SYSTEM
Cross-Sectional ViewINFOID:0000000001703161
Shift MechanismINFOID:0000000001703162
CONSTRUCTION
1. Converter housing 2. Oil pump 3. Brake band
4. Reverse clutch 5. High clutch 6. Front planetary gear
7. Low one-way clutch 8. Rear planetary gear 9. Forward clutch
10. Overrun clutch 11. Low & reverse brake 12. Output gear
13. Band servo piston 14. Reverse clutch drum 15. Side cover
16. Idler gear 17. Forward one-way clutch 18. Transaxle case
19. Reduction pinion gear 20. Final gear 21. Differential case
22. Input shaft 23. Torque converter
SCIA7938E

AT-20
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A/T CONTROL SYSTEM
FUNCTION OF CLUTCH AND BRAKE
CLUTCH AND BAND CHART
1. Torque converter 2. Oil pump 3. Input shaft
4. Brake band 5. Reverse clutch 6. High clutch
7. Front sun gear 8. Front pinion gear 9. Front internal gear
10. Front planetary carrier 11. Rear sun gear 12. Rear pinion gear
13. Rear internal gear 14. Rear planetary carrier 15. Forward clutch
16. Forward one-way clutch 17. Overrun clutch 18. Low one-way clutch
19. Low & reverse brake 20. Parking pawl 21. Parking gear
22. Output shaft 23. Idle gear 24. Output gear
SAT998I
Clutch and brake components Abbr. Function
5Reverse clutch R/C To transmit input power to front sun gear 7.
6High clutch H/C To transmit input power to front planetary carrier 10.
15Forward clutch F/C To connect front planetary carrier 10 with forward one-way clutch 16.
17Overrun clutch O/C To connect front planetary carrier 10 with rear internal gear 13.
4Brake band B/B To lock front sun gear 7.
16Forward one-way clutch F/O.CWhen forward clutch 15 is engaged, to stop rear internal gear 13 from rotating in
opposite direction against engine revolution.
18Low one-way clutch L/O.CTo stop front planetary carrier 10 from rotating in opposite direction against en-
gine revolution.
19Low & reverse brake L & R/B To lock front planetary carrier 10.
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 re-
lease4th ap-
ply
PPA R K
POSITION
RREVERSE
POSITION
NNEUTRAL
POSITION
D*4 1st *1D B B

A/T CONTROL SYSTEM
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• *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 “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.
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
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 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 re-
lease4th ap-
ply
SAT991I

AT-22
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
“D1” 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 brakeAs 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 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.

A/T CONTROL SYSTEM
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P “D
2”, “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 bandRear 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 conditionsD
2: OD OFF (OD OFF indicator lamp is on) and throttle opening is less than specification*
2
2 and 12: Always engaged

AT-24
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
“D3”, “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
clutchInput 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 conditionsD
3: OD OFF (OD OFF indicator lamp is on) and throttle opening is less than specification*
2
3 and 13: Always engaged

A/T CONTROL SYSTEM
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P “D
4” (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 brakeAt D
4 position, there is no one-way clutch in the power transaxle line and engine brake
can be obtained when decelerating.

AT-26
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
“R” Position
SAT380J
•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.

A/T CONTROL SYSTEM
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TCM FunctionINFOID:0000000001703163
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.
SAT381J
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-III 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

AT-28
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000001703164
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-6,
&#34;System Description&#34;.
Input/Output Signal of TCMINFOID:0000000001703165
SCIA7112E
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) X X X (*4) X
Wide open throttle position signal
(*5)(*2) X (*2) X (*4) X
Turbine revolution sensor (Power
train revolution sensor)XXXXX
Engine speed signal X X X X
PNP switch 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 X X X