NISSAN LATIO 2009 Service Repair Manual

CVT FLUID
CVT-197
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FLUID CONDITION CHECK
Changing CVT Fluid INFOID:0000000004305571
1. Warm up CVT fluid by driving the vehicle for 10 minutes.
• : Vehicle front
• Radiator (2)
• CVT fluid cooler hose [inlet side (3)]
• Transaxle assembly (4)
2. Drain CVT fluid from CVT fluid cooler hose [outlet side (1)] and refill with new specified NISSAN CVT fluid in the CVT fluid
charging pipe with the engine running at idle speed.
CAUTION:
Only use the specifi ed NISSAN CVT fluid.
3. Refill until new CVT fluid comes out from CVT fluid cooler hose [outlet side (1)]. NOTE:
About 30 to 50% extra fluid will be required for this procedure.
4. Check fluid level and condition. Refer to CVT-196, " Checking CVT Fluid " .
CAUTION:
Delete CVT fluid deterioration date with CO NSULT-III after changing CVT fluid. Refer to CVT-230," CONSULT-III Function (TRANSMISSION) " .
CVT Fluid Cooler Cleaning INFOID:0000000004305572
Whenever a CVT is repaired, overhauled, or replaced, t he CVT fluid cooler mounted in the radiator must be
inspected and cleaned.
Metal debris and friction material, if present, can be trapped or become deposit in the CVT fluid cooler. This
debris can contaminate the newly serviced CVT or, in severe cases, can block or restrict the flow of CVT fluid.
In either case, malfunction of the newly serviced CVT may occur.
Debris, if present, may deposit as CVT fluid enters the cool er inlet. It will be necessary to back flush the cooler
through the cooler outlet in order to flush out any built up debris.
CVT FLUID COOLER CLEANING PROCEDURE 1. Identify the CVT inlet and outlet fluid cooler hoses.
2. Position an oil pan under the inlet and outlet cooler hoses. Fluid status Conceivable cause Required operation
Varnished (viscous
varnish state) Clutch, brake
scorched Replace the CVT fluid and check the
CVT main unit and the vehicle for
malfunctions (wire harness, cooler
pipes, etc.)
Milky white or cloudy Water in the fluid Replace the CVT fluid and check for places where water is getting in.
Large amount of
metal powder mixed
in fluid Unusual wear of
sliding parts within
CVT Replace the CVT fluid and check for
improper operation of the CVT. ATA0022D
Fluid capacity and grade: Refer to
MA-14, " Fluids
and Lubricants " .
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CVT-198< SERVICE INFORMATION >
[RE0F08B]
CVT FLUID
3. Disconnect the fluid cooler inle t and outlet rubber hoses from the
steel cooler tubes.
NOTE:
Replace the cooler hoses if rubber material from the hose
remains on the tube fitting.
4. Allow any CVT fluid that remains in the cooler hoses to drain into the oil pan.
5. Insert the extension adapter hose of a can of Transmission
Cooler Cleaner (Nissan P/N 999MP-AM006) into the cooler out-
let hose.
CAUTION:
• Wear safety glasses and rubber gloves when spraying the Transmission Cooler Cleaner.
• Spray Transmission Cooler Cleaner only with adequate
ventilation.
• Avoid contact with eyes and skin.
• Do not breath vapors or spray mist.
6. Hold the hose and can as high as possible and spray Transmis- sion Cooler Cleaner in a continuous stream into the cooler outlet
hose until CVT fluid flows out of the cooler inlet hose for 5 seconds.
7. Insert the tip of an air gun into the end of the cooler outlet hose.
8. Wrap a shop rag around the air gun tip and of the cooler outlet hose.
9. Blow compressed air regulated to 5 to 9 kg/cm 2
(71 to 128 psi)
through the cooler outlet hose for 10 seconds to force out any
remaining CVT fluid.
10. Repeat steps 5 through 9 three additional times.
11. Position an oil pan under the banjo bolts that connect the CVT fluid cooler steel lines to the transaxle.
12. Remove the banjo bolts.
13. Flush each steel line from the cooler side back toward the tran- saxle by spraying Transmission Cooler Cleaner in a continuous stream for 5 seconds.
14. Blow compressed air regulated to 5 to 9 kg/cm 2
(71 to 128 psi) through each steel line from the cooler
side back toward the transaxle for 10 seconds to force out any remaining CVT fluid.
15. Ensure all debris is removed from the steel cooler lines.
16. Ensure all debris is removed from the banjo bolts and fittings.
17. Perform "CVT FLUID COOLER DIAGNOSIS PROCEDURE".
CVT FLUID COOLER DIAGNOSIS PROCEDURE
NOTE:
Insufficient cleaning of the cooler inlet hose exte rior may lead to inaccurate debris identification.
1. Position an oil pan under the transaxle's inlet and outlet cooler hoses.
2. Clean the exterior and tip of the cooler inlet hose. SCIA4421E
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CVT FLUID
CVT-199
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3. Insert the extension adapter hose of a can of Transmission
Cooler Cleaner (Nissan P/N 999MP-AM006) into the cooler out-
let hose.
CAUTION:
• Wear safety glasses and rubber gloves when spraying the Transmission Cooler Cleaner.
• Spray Transmission Cooler Cleaner only with adequate
ventilation.
• Avoid contact with eyes and skin.
• Do not breath vapors or spray mist.
4. Hold the hose and can as high as possible and spray Transmis- sion Cooler Cleaner in a continuous stream into the cooler outlet
hose until CVT fluid flows out of t he cooler inlet hose for 5 seconds.
5. Tie a common white, basket-type coffee filter to the end of the cooler inlet hose.
6. Insert the tip of an air gun into the end of the cooler outlet hose.
7. Wrap a shop rag around the air gun tip and end of cooler outlet hose.
8. Blow compressed air regulated to 5 to 9 kg/cm 2
(71 to 128 psi)
through the cooler outlet hose to force any remaining CVT fluid
into the coffee filter.
9. Remove the coffee filter from the end of the cooler inlet hose.
10. Perform "CVT FLUID COOLER INSPECTION PROCEDURE".
CVT FLUID COOLER INSPECTION PROCEDURE 1. Inspect the coffee filter for debris.
a. If small metal debris less than 1 mm (0.040 in) in size or metal powder is found in the coffee filter, this is normal. If normal
debris is found, the CVT fluid cooler/radiator can be re-used and
the procedure is ended. SCIA4421E
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CVT-200< SERVICE INFORMATION >
[RE0F08B]
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

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

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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

" System Description " .
Input/Output Signal of TCM INFOID:0000000004305578 B

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-206< 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. SCIA7958E
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