2010 NISSAN LATIO TCM controls the throttle

AT-30
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
TCM Function
INFOID:0000000005397221
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: January 20102010 Versa

AT-34
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
CONTROL OF SHIFT VALVES A AND B
Pilot pressure generated by the operation of shift solenoid valves A and B is applied to the end face of shift
valves A and B.
The figure above shows the operation of shift valve B. When the shift solenoid valve is “ON”, pilot pressure
applied to the end face of the shift valve overcomes spring force, moving the valve upward.
Lock-up ControlINFOID:0000000005397226
The torque converter clutch piston in the torque conver ter is locked to eliminate torque converter slip and to
increase power transmission efficiency. The solenoid va lve is controlled by an ON-OFF duty signal sent from
the TCM. The signal is converted to an oil pressure si gnal which controls the torque converter clutch piston.
CONDITIONS FOR LOCK-UP OPERATION
When vehicle is driven in 3GR and 4GR positions, v ehicle speed and throttle opening are detected. If the
detected values fall within the lock-up zone me morized in the TCM, lock-up is performed.
TORQUE CONVERTER CLUTCH SOLENOID VALVE CONTROL
Gear position123 4
Shift solenoid valve A ON (Closed)OFF (Open)OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed)ON (Closed) OFF (Open) OFF (Open)
SAT009J
OD ONOFF
Selector lever “D” position
Gear position D
4D3
Vehicle speed signal More than set value
Accelerator pedal position signal Less than set opening
Closed throttle position signal OFF
A/T fluid temperature sensor More than 40°C (104 °F)
Revision: January 20102010 Versa

AT-42
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
DTC Inspection Priority ChartINFOID:0000000005397235
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC “CAN COMM CIRCUIT” is displayed with other DTCs, first perform the trouble diagnosis for
DTC “CAN COMM CIRCUIT”. Refer to AT- 8 7
.
Fail-SafeINFOID:0000000005397236
The TCM has an electronic Fail-safe mode. This allows t he vehicle to be driven even if a major electrical input/
output device circuit is damaged.
Under Fail-Safe, the vehicle always runs in 3GR, even wit h a shift lever position of “1”, “2” or “D”. The cus-
tomer may complain of sluggish or poor acceleration.
Always follow the “ AT-43, "
How to Perform Trouble Diagnosis for Quick and Accurate Repair" ”.
The SELF-DIAGNOSIS results will be as follows:
• The first SELF-DIAGNOSIS will indicate damage to the vehicle speed signal or the output speed sensor.
• During the next SELF-DIAGNOSIS, performed after checking the sensor, no damages will be indicated.
FAIL-SAFE FUNCTION
The following fail-safe functions allow vehicles to be driven even when sensor, switch or solenoid malfunction
occurs.
Output Speed Sensor
Vehicle speed signal is input from combination meter.
Accelerator Pedal Position Signal and Throttle Position Signal
TCM controls the throttle opening angle to a predetermined fixed position to enable driving if a malfunctioning
signal is input to TCM.
Transmission Range Switch
When the multiple transmission range switch signals are input to TCM, the priority of selector lever position
becomes “D”, “N”, “R”, “2” and “1” in order by internal TCM determination.
The use of 4GR is inhibited until normal operation resumes. Because the hydraulic circuit of the control valve
is switched by manual valve according to the selector lever position, however, actual operating condition of
vehicle becomes as follows.
Shift Solenoid Valve A and B
If non-standard solenoid signal is sent to TCM, use of certain gears is limited. Refer to chart shown below.
Priority Detected items
1 CAN communication line
2 Except above
Actual lever positionTransmission range switch input signal Running status
“P” “P” position and other position signals P
“R” “R” position and other position signals R
“N” “N” position and other position signals N
“D” “D” position and other position signals D
1 ⇔ D2 ⇔ D3 ⇔ D4
“2” “2” position and other position signals (Except “1” position)
21 ⇔ 22 ⇔ 23
“2” position and “1” position signals 21 ⇔ 22
“1” “1” position and other position signals (Except “2” position)
11 ⇔ 12 ⇔ 13
“1” position and “2” position signals 11 ⇔ 12
Revision: January 20102010 Versa

CVT SYSTEMCVT-21
< SERVICE INFORMATION > [RE0F08B]
D
E
F
G H
I
J
K L
M A
B
CVT
N
O P
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 SYSTEMCVT-23
< SERVICE INFORMATION > [RE0F08B]
D
E
F
G H
I
J
K L
M A
B
CVT
N
O P
*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 SYSTEMCVT-25
< SERVICE INFORMATION > [RE0F08B]
D
E
F
G H
I
J
K L
M A
B
CVT
N
O P
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

EC-522
< SERVICE INFORMATION >[MR18DE]
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System DescriptionINFOID:0000000005532386
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can set
vehicle speed in advance between approximately 40 km/
h (25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric thro ttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indi cator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
NOTE:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws.
SET OPERATION
Press MAIN switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press SET/COAST switch. (Then SET indi cator in combination meter illuminates.)
ACCELERATE OPERATION
If the RESUME/ACCELERATE switch is depressed during cruise control driving, increase the vehicle speed
until the switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.
• CANCEL switch is pressed
• More than two switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)
• Brake pedal is depressed
• Clutch pedal is depressed or gear position is changed to the neutral position (M/T models)
• Selector lever is changed to N, P, R position (A/T and CVT models)
• Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.
• Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing SET/COAST switch or RESUME/
ACCELERATE switch.
• Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If MAIN switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled and vehicle
speed memory will be erased.
COAST OPERATION
Sensor Input signal to ECM ECM functionActuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator
Stop lamp switch
Brake pedal operation
ASCD clutch switch (M/T models) Clutch pedal operation
ASCD steering switch ASCD steering switch operation
Park/neutral position (PNP) signal Gear position
ABS actuator and electric unit (con-
trol unit) Vehicle speed*
Combination meter
TCM Powertrain revolution*
Revision: January 20102010 Versa