NISSAN LATIO 2010 Service Repair Manual

CVT-18
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CVT FLUID
b. If one or more pieces of debris are found that are over 1 mm
(0.040 in) in size and/or peeled clutch facing material is found in
the coffee filter, the fluid cooler is not serviceable. The radiator/
fluid cooler must be replac ed and the inspection procedure is
ended.
CVT FLUID COOLER FINAL INSPECTION
After performing all procedures, ensure that all remaining oil is cleaned from all components.
SCIA7031E
Revision: January 20102010 Versa

CVT SYSTEMCVT-19
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CVT SYSTEM
Cross-Sectional View - RE0F08BINFOID:0000000005397770
1. Converter housing 2. Oil pump3. Forward clutch
4. Reverse brake 5. Planetary carrier6. Primary pulley
7. Steel belt 8. Sun gear9. Side cover
10. Internal gear 11. Secondary pulley12. Differential case
13. Final gear 14. Idler gear15. Reduction gear
16. Output gear 17. Parking gear18. Input shaft
19. Torque converter
SCIA8015E
Revision: January 20102010 Versa

CVT-20
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CVT SYSTEM
Control System
INFOID:0000000005397771
AWDIA0767GB
Revision: January 20102010 Versa

CVT SYSTEMCVT-21
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Hydraulic Control SystemINFOID:0000000005397772
TCM FunctionINFOID:0000000005397773
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 various sensors. It always controls the optimum shift
position and reduces shifting and lock-up shocks.
AWDIA0768GB
SENSORS (or SIGNAL)
⇒TCM
⇒ACTUATORS
Transmission range 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
Revision: January 20102010 Versa

CVT-22
< SERVICE INFORMATION >[RE0F08B]
CVT SYSTEM
CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000005397774
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 s
peed 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 CA N 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:0000000005397775
AWDIA0769GB
Control itemFluid
pressure control Select con-
trol Shift control Lock-up
control CAN com-
munication control Fail-safe
function (*3)
Input T
ra n sm is sio n r ang e s wit c h XXXXXX
Accelerator pedal position signal
(*1)XXXXXX
Closed throttle position signal
(*1)X XXX
Engine speed signal
(*1)XX XXX
CVT fluid temperature sensor XX XX X
Stop lamp switch signal
(*1)X XXX
Overdrive control signal
(*1)XX
Primary speed sensor X XXXX
Secondary speed sensor XXXXXX
Secondary pressure sensor XX X
T C M pow er s upp ly v olt a ge s ig n al XXXXXX
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CVT SYSTEMCVT-23
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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 ControlINFOID:0000000005397776
• 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 transmission range switch signal, the lock-up signal, the voltage, the target
gear ratio, the fluid temperat ure, 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 ControlINFOID:0000000005397777
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-
putSte p mo tor
XX
TCC solenoid valve XXX
Lock-up select solenoid valve XXX
Line pressure solenoid valve XXX X
Secondary pressure solenoid valve XX X
O/D OFF indicator signal
(*2)XX
Control item
Fluid
pressure
control Select con-
trol Shift control
Lock-up
control CAN com-
munication
control Fail-safe
function
(*3)
SCIA1846E
Revision: January 20102010 Versa

CVT-24
< SERVICE INFORMATION >[RE0F08B]
CVT SYSTEM
mand to the step motor, and control the flow-in/flow-out of line pressure from the primary pulley to determine
the position of the moving-pulley and control the gear ratio.
NOTE:
The gear ratio is set for every position separately.
“D” POSITION
Shifting over all the ranges of gear ratios from the lowest to the high-
est.
OVERDRIVE-OFF MODE
Use this position for the improved engine braking.
“L” POSITION
By limiting the gear range to the lowest position, the strong driving
force and the engine brake can be secured.
DOWNHILL ENGINE BRAKE CONTROL
(AUTO ENGINE BRAKE CONTROL)
When downhill is detected with the accelerator pedal released, the engine brake will be strengthened up by
downshifting so as not to accelerate the vehicle more than necessary.
ACCELERATION CONTROL
According to vehicle speed and a change of accelerator pedal angle, driver's request for acceleration and driv-
ing scene are judged. This function assists improvem ent in acceleration feeling by making the engine speed
proportionate to the vehicle speed. And a shift map which can gain a larger driving force is available for com-
patibility of mileage with driveability.
AWDIA0770GB
SCIA1953E
SCIA1955E
Revision: January 20102010 Versa

CVT SYSTEMCVT-25
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Lock-up and Select ControlINFOID:0000000005397778
• 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 ValveINFOID:0000000005397779
FUNCTION OF CONTROL VALVE
SCIA1958E
AWDIA0778GB
Revision: January 20102010 Versa

CVT-26
< SERVICE INFORMATION >[RE0F08B]
CVT SYSTEM
Name
Function
Torque converter regulator valve Optimizes the supply pressure for the torque converter depending on driving conditions.
Pressure regulator valve Optimizes the discharge pressure from the oil pump depending on driving conditions.
TCC control valve • Activates or deactivate the lock-up.
• Lock-up smoothly by opening lock-up operation excessively.
TCC solenoid valve Controls the TCC control valve or select control valve.
Shift control valve Controls flow-in/out of line pressure from the primary pulley depending on the stroke dif-
ference between the stepping motor and the primary pulley.
Secondary valve Controls the line pressure from the secondary pulley depending on operating conditions.
Clutch regulator valve Adjusts the clutch operating pressure depending on operating conditions.
Secondary pressure solenoid valve Controls the secondary valve.
Line pressure solenoid valve Controls the line pressure control valve.
Step motor Controls the pulley ratio.
Manual valve Transmits the clutch operating pressure to each circuit in accordance with the selected
position.
Select control valve Engages forward clutch, reverse brake smoothly depending on select operation.
Select switch valve Switches torque converter clutch solenoid valve control pressure use to torque converter
clutch control valve or select control valve.
Lock-up select solenoid valve Controls the select switch valve.
Revision: January 20102010 Versa

ON BOARD DIAGNOSTIC (OBD) SYSTEMCVT-27
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
IntroductionINFOID:0000000005397780
The CVT system has two self-diagnostic systems.
The first is the emission-related on board diagnostic syst em (OBD-II) performed by the TCM in combination
with the ECM. The malfunction is indicated by the MI L (malfunction indicator lamp) and is stored as a DTC in
the ECM memory, and the TCM memory.
The second is the TCM original self-diagnosis perform ed by the TCM. The malfunction is stored in the TCM
memory. The detected items are overlapped with OBD-II self-diagnostic items. For detail, refer to CVT-48,
"CONSULT-III Function (TRANSMISSION)".
OBD-II Function for CVT SystemINFOID:0000000005397781
The ECM provides emission-related on board diagnostic (OBD-II) functions for the CVT system. One function
is to receive a signal from the TCM used with OBD-relat ed parts of the CVT system. The signal is sent to the
ECM when a malfunction occurs in the corresponding OBD-re lated part. The other function is to indicate a
diagnostic result by means of the MIL (malfunction indica tor lamp) on the instrument panel. Sensors, switches
and solenoid valves are used as sensing elements.
The MIL automatically illuminates in One or Two Trip Detection Logic when a malfunction is sensed in relation
to CVT system parts.
One or Two Trip Detection Logic of OBD-IIINFOID:0000000005397782
ONE TRIP DETECTION LOGIC
If a malfunction is sensed during the first test drive, the MIL will illuminate and the malfunction will be stored in
the ECM memory as a DTC. The TCM is not provided with such a memory function.
TWO TRIP DETECTION LOGIC
When a malfunction is sensed during the first test drive, it is stored in the ECM memory as a 1st trip DTC
(diagnostic trouble code) or 1st trip freeze frame data. At this point, the MIL will not illuminate. — 1st trip
If the same malfunction as that experienced during the fi rst test drive is sensed during the second test drive,
the MIL will illuminate. — 2nd trip
The “trip” in the “One or Two Trip Detection Logic” m eans a driving mode in which self-diagnosis is performed
during vehicle operation.
OBD-II Diagnostic Trouble Code (DTC)INFOID:0000000005397783
HOW TO READ DTC AND 1ST TRIP DTC
DTC and 1st trip DTC can be read by the following methods.
( with CONSULT-III or GST) CONSULT-III or GST (Generic Scan Tool) Examples: P0705, P0720 etc.
These DTC are prescribed by SAE J2012.
(CONSULT-III also displays the malfunctioning component or system.)
• 1st trip DTC No. is the same as DTC No.
• Output of the diagnostic trouble code indicates that the indicated circuit has a malfunction. How-
ever, in case of the Mode II and GST, they do not indicate whether the malfunction is still occurring or
occurred in the past and returned to normal.
CONSULT-III can identify them as shown below, therefore, CONS ULT-III (if available) is recom-
mended.
DTC or 1st trip DTC of a malfunction is displayed in SELF-DIAGNOSTIC RESULTS mode for “ENGINE” with
CONSULT-III. Time data indicates how many times the vehicle was driven after the last detection of a DTC.
If the DTC is being detected curr ently, the time data will be “0”.
If a 1st trip DTC is stored in the ECM, the time data will be “1t”.
Freeze Frame Data and 1st Trip Freeze Frame Data
Revision: January 20102010 Versa