2009 NISSAN LATIO torque

CVT-184< SERVICE INFORMATION >
[RE0F08A]
TRANSAXLE ASSEMBLY
• When installing the cooler outlet tube (1) to the transaxle assembly (2), align the cooler tube bracket (A) against the transaxle as
shown.
• When installing the transaxle to the engine, align t he matching mark on the drive plate with the matching
mark on the torque converter alignment stud.
• When securing the transaxle to the engine, attach the bolts in
accordance with the following standard.
• When installing the drive plate to torque converter nuts, tighten them temporarily. Then tighten the nuts to the specified torque.
• After completing installation check for fluid level, fluid leakage, and the positions of CVT. Refer to CVT-17," Checking CVT Fluid " ,
CVT-175, " Adjustment of CVT Position " and
CVT-175, " Checking of CVT Position " .
• When replacing the CVT assembly, erase EEP ROM in TCM. Refer to CVT-12, " Service After Replacing
TCM and Transaxle Assembly " . WCIA0618E
Bolt No. 1 (Transaxle to engine) 2 (Engine to transaxle)
Number of bolts 2 7
Bolt length
“A” mm (in) 55 (2.17) 50 (1.97)
Tightening torque
N·m (kg-m, ft-lb) 62 (6.3, 46) WCIA0619E
Converter nuts: : 51 N·m (5.2 kg-m, 38 ft-lb)
WCIA0616E

CVT SYSTEM
CVT-201
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CVT SYSTEM
Cross-Sectional View - RE0F08B INFOID:0000000004305573
1. Converter housing 2. Oil pump 3. Forward clutch
4. Reverse brake 5. Planetary carrier 6. Primary pulley
7. Steel belt 8. Sun gear 9. Side cover
10. Internal gear 11. Secondary pulley 12. Differential case
13. Final gear 14. Idler gear 15. Reduction gear
16. Output gear 17. Parking gear 18. Input shaft
19. Torque converter SCIA8015E

CVT SYSTEM
CVT-203
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Hydraulic Control System
INFOID:0000000004305575
TCM Function INFOID:0000000004305576
The function of the TCM is to:
• Receive input signals sent from various switches and sensors.
• Determine required line pressure, shifting point, and lock-up operation.
• Send required output signals to the step motor and the respective solenoids.
CONTROL SYSTEM OUTLINE The CVT senses vehicle operating conditions through vari ous sensors. It always controls the optimum shift
position and reduces shifting and lock-up shocks. SCIA1807E
SENSORS (or SIGNAL)
⇒TCM
⇒ACTUATORS
PNP switch
Accelerator pedal position signal
Closed throttle position signal
Engine speed signal
CVT fluid temperature sensor
Vehicle speed signal
Overdrive control signal
Stop lamp switch signal
Primary speed sensor
Secondary speed sensor
Secondary pressure sensor Shift control
Line pressure control
Primary pressure control
Secondary pressure control
Lock-up control
Engine brake control
Vehicle speed control
Fail-safe control
Self-diagnosis
CONSULT-III co mmunication
line
Duet-EA control
CAN system
On board diagnosis Step motor
Torque converter clutch solenoid
valve
Lock-up select solenoid valve
Line pressure solenoid valve
Secondary pressure solenoid
valve
Shift position indicator
O/D OFF indicator lamp
Starter relay

CVT SYSTEM
CVT-205
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*1: Input by CAN communications.
*2: Output by CAN communications.
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
Line Pressure and Secondary Pressure Control INFOID:0000000004305579
• When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the TCM
controls the line pressure solenoid valve and secondary pressure solenoid valve.
• This line pressure solenoid controls the pressure regulat or valve as the signal pressure and adjusts the pres-
sure of the operating oil discharged from the oil pump to the line pressure most appropriate to the driving
state. Secondary pressure is cont rolled by decreasing line pressure.
NORMAL CONTROL Optimize the line pressure and secondary pressure, dependi ng on driving conditions, on the basis of the throt-
tle position, the engine speed, the primary pulley (input ) revolution speed, the secondary pulley (output) revo-
lution speed, the brake signal, the PNP switch signal, the lock-up signal, the voltage, the target gear ratio, the
fluid temperature, and the fluid pressure.
FEEDBACK CONTROL When controlling the normal fluid pressure or the sele cted fluid pressure, the secondary pressure can be set
more accurately by using the fluid pressure sensor to detect the secondary pressure and controlling the feed-
back.
Shift Control INFOID:0000000004305580
In order to select the gear ratio which can obtain the dr iving force in accordance with driver's intention and the
vehicle condition, TCM monitors the driving conditions, such as the vehicle speed and the throttle position and
selects the optimum gear ratio, and determines the gear change steps to the gear ratio. Then send the com-
Out-
put Step motor X X
TCC solenoid valve X X X
Lock-up select solenoid valve X X X
Line pressure solenoid valve X X X X
Secondary pressure solenoid valve X X X
O/D OFF indicator signal (*2)
X X
Control item
Fluid
pressure
control Select con-
trol Shift control
Lock-up
control CAN com-
munication
control Fail-safe
function
(*3) SCIA1846E

CVT SYSTEM
CVT-207
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Lock-up and Se
lect Control INFOID:0000000004305581
• The torque converter clutch piston in the torque conv erter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
• The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid
valve, which is controlled by a signal from TCM. The torque converter clutch control valve engages or
releases the torque converter clutch piston.
• When shifting between “N” (“P”) ⇔ “D” (“R”), torque converter clutch solenoid controls engagement power of
forward clutch and reverse brake.
• The lock-up applied gear range was expanded by locking up the torque converter at a lower vehicle speed than conventional CVT
models.
TORQUE CONVERTER CLUTCH AND SELECT CONTROL VALVE CONTROL
Lock-up and Select Control System Diagram
Lock-up Released In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the
torque converter clutch solenoid and the lock-up apply pressure is drained.
In this way, the torque converter clutch piston is not coupled.
Lock-up Applied In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the torque
converter clutch solenoid and lock-up apply pressure is generated.
In this way, the torque converter clutch piston is pressed and coupled.
Select Control When shifting between “N” (“P”) ⇔“D” (“R”), optimize the operating pressure on the basis of the throttle posi-
tion, the engine speed, and the secondary pulley (out put) revolution speed to lessen the shift shock.
Control Valve INFOID:0000000004305582
FUNCTION OF CONTROL VALVE SCIA1958E
SCIA2374E

.
Fail-Safe INFOID:0000000004305589
The TCM has an electrical fail-safe mode. This mode make s it possible to operate even if there is an error in a
main electronic control input/output signal circuit.
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, th is function controls the CVT to make driving possible.
Output Speed Sensor (S econdary Speed Sensor)
The shift pattern is changed in accordance with thrott le position when an unexpected signal is sent from the
output speed sensor (secondary speed sensor) to the TCM. The overdrive-off mode is inhibited, and the tran-
saxle is put in “D”.
Input Speed Sensor (Primary Speed Sensor)
The shift pattern is changed in accordance with thro ttle position and secondary speed (vehicle speed) when
an unexpected signal is sent from the input speed sensor (primary speed sensor) to the TCM. The overdrive-
off mode is inhibited, and the transaxle is put in “D”.
PNP Switch
If an unexpected signal is sent from the PNP switch to the TCM, the transaxle is put in “D”.
CVT Fluid Temperature Sensor
If an unexpected signal is sent from the CVT fluid temper ature sensor to the TCM, the gear ratio in use before
receiving the unexpected signal is maintained or t he gear ratio is controlled to keep engine speed under 3500
rpm.
Transmission Fluid Pressure Sensor A (Secondary Pressure Sensor)
• If an unexpected signal is sent from the transmission fluid pressure sensor A (secondary pressure sensor) to
the TCM, the secondary pressure feedback control is stopped and the offset value obtained before the non-
standard condition occurs is used to control line pressure.
• If transmission fluid pressure sensor A (secondary pres sure sensor) error signal is input to TCM, secondary
pressure feedback control stops, but line pressure is controlled normally.
Pressure Control Solenoid A (Line Pressure Solenoid)
If an unexpected signal is sent from the solenoid to t he TCM, the pressure control solenoid A (line pressure
solenoid) is turned OFF to achieve the maximum fluid pressure.
Pressure Control Solenoid B (Secondary Pressure Solenoid)
If an unexpected signal is sent from the solenoid to t he TCM, the pressure control solenoid B (secondary pres-
sure solenoid) is turned OFF to achieve the maximum fluid pressure.
Torque Converter Clutch Solenoid
If an unexpected signal is sent from the solenoid to t he TCM, the torque converter clutch solenoid is turned
OFF to cancel the lock-up.
Step Motor
If an unexpected signal is sent from the step motor to the TCM, the step motor coil phases “A” through “D” are
all turned OFF to hold the gear ratio used right before the non-standard condition occurred.
CVT Lock-up Select Solenoid Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSIS
CVT-213
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If an unexpected signal is sent from the solenoid to t
he TCM, the CVT lock-up select solenoid is turned OFF to
cancel the lock-up.
TCM Power Supply (Memory Back-up) Transaxle assembly is protected by limiting the engine torque when the memory back-up power supply (for
controlling) from the battery is not supplied to TCM. Normal statues is restored when turning the ignition switch
OFF to ON after the normal power supply.
How to Perform Trouble Diagnosis for Quick and Accurate Repair INFOID:0000000004305590
INTRODUCTION The TCM receives a signal from the vehicle speed sensor , PNP switch and provides shift control or lock-up
control via CVT solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used wit h the OBD-related parts of the
CVT system for malfunction-diagnos tic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the CVT system. The CVT system must be in good
operating condition and be free of valve seizure, solenoid valve mal-
function, etc.
It is much more difficult to diagnose an error that occurs intermit-
tently rather than continuously. Most intermittent errors are caused
by poor electric connections or impr oper wiring. In this case, careful
checking of suspected circuits may help prevent the replacement of
good parts.
A visual check only may not find t he cause of the errors. A road test
with CONSULT-III (or GST) or a circuit tester connected should be
performed. Follow the "WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” as
shown on the example (Refer to "Diagnostic Worksheet Chart" )
should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
WORK FLOW A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a malf unction. It is important to fully understand the symp-
toms or conditions for a customer complaint.
Make good use of the two sheets provided, "Informati on From Customer" and "Diagnostic Worksheet Chart" ,
to perform the best troubleshooting possible.
Work Flow Chart SAT631IB
SAT632I
SEF234G

TROUBLE DIAGNOSIS
CVT-221
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6. While holding down the foot brake, gradually press down the
accelerator pedal.
7. Quickly read off the stall speed, and then quickly remove your foot from the accelerator pedal.
CAUTION:
Do not hold down the accelerat or pedal for more than 5 sec-
onds during this test.
8. Move the selector lever to the “N” position.
9. Cool down the CVT fluid. CAUTION:
Run the engine at idle for at least 1 minute.
10. Repeat steps 6 through 9 with selector lever in “R” position.
Judgement Stall Test
O: Stall speed within standard value position.
H: Stall speed is higher than standard value.
L: Stall speed is lower than standard value.
LINE PRESSURE TEST
Line Pressure Test Port
Line Pressure Test Procedure 1. Inspect the amount of engine oil and replenish if necessary.
2. Drive the car for about 10 minutes to warm it up so that the CVT fluid reaches in the range of 50 to 80°C
(122 to 176 °F), then inspect the amount of CVT fluid and replenish if necessary.
NOTE: Stall speed:
CVT-357, " Stall Speed "
SAT514G
SAT771B
Selector lever position
Expected problem location
“D” “R”
Stall rotation H O • Forward clutch
O H • Reverse brake L L • Engine and torque converter one-way clutch
H H • Line pressure low
• Primary pulley
• Secondary pulley
• Steel belt SCIA6184E