TM-232
< SYSTEM DESCRIPTION >[CVT: RE0F10E]
SYSTEM
SYSTEM
CVT CONTROL SYSTEM
CVT CONTROL SYSTEM :
System DescriptionINFOID:0000000009464204
SYSTEM DIAGRAM
MAIN CONTROL CONTENTS OF TCM
SYSTEM DESCRIPTION
AWDIA1097GB
Controls Reference
Line pressure control TM-237, "LINE PRESSURE CONTROL : System Description"
Shift control TM-238, "SHIFT CONTROL : System Description"
Select controlTM-239, "SELECT CONTROL : System Description"
Lock-up control TM-240, "LOCK-UP CONTROL : System Description"
Fail-safe TM-258, "Fail-safe"
Self-diagnosis functionTM-245, "CONSULT Function"
Communication function with CONSULT TM-245, "CONSULT Function"
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
SYSTEMTM-233
< SYSTEM DESCRIPTION > [CVT: RE0F10E]
C
EF
G H
I
J
K L
M A
B
TM
N
O P
• CVT detects the vehicle driving status from switc hes, sensors and signals, and controls the vehicle so that
the optimum shift position and shift timing may always be achieved. It also controls the vehicle to reduce
shift and lockup shock, etc.
• Receives input signals from switches and sensors.
• Sends the output signal necessary for operation of so lenoid valves, and evaluates the line pressure, shift
timing, lockup operation, engine brake performance, etc.
• If a malfunction occurs on the electric system, activa te the fail-safe mode only to drive the vehicle.
LIST OF CONTROL ITEMS AND INPUT/OUTPUT
*: If these input/output signals show errors, TCM activates the fail-safe function.
CVT CONTROL SYSTEM : Fail-safeINFOID:0000000009464205
TCM has a fail-safe mode. The mode functions so that operation can be continued even if the signal circuit of
the main electronically controlled input/output parts is damaged.
If the vehicle shows following behaviors including “poor acceleration”, a malfunction of the applicable system
is detected by TCM and the vehicle may be in a fail-s afe mode. At this time, check the DTC code and perform
inspection and repair according to the malfunction diagnosis procedures.
Fail-safe function
Control Item Shift control Line pressure
control Select control Lock-up con-
trol Fail-safe func-
tion*
Input Engine torque signal
(CAN communication) ×××××
Engine speed signal
(CAN communication) ×××××
Accelerator pedal position signal
(CAN communication) ××××
Closed throttle position signal
(CAN communication) ×× ×
Stop lamp switch signal
(CAN communication) ××××
Primary pressure sensor ×
Secondary pressure sensor ×× ×
CVT fluid temperature sensor ×××××
Primary speed sensor ×××××
Output speed sensor ×× ××
Input speed sensor ×××××
Transmission range switch ×××××
Paddle shifter
(CAN communication) ×× ×
Output Line pressure solenoid valve
××× ×
Primary pressure solenoid valve ×× ×
Torque converter clutch solenoid
valve ××
Secondary pressure solenoid valve ×× ×
Select solenoid valve ×××
Shift position indicator
(CAN communication) ×
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
SYSTEMTM-235
< SYSTEM DESCRIPTION > [CVT: RE0F10E]
C
EF
G H
I
J
K L
M A
B
TM
N
O P
P0776 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed
• Vehicle speed is not increased When a malfunction occurs on the low oil pressure side
• Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed When a malfunction occurs on the high oil pressure side
P0778 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P0779 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed
P0841 • Not changed from normal driving
P0847 • Not changed from normal driving —
P0848 • Not changed from normal driving —
P084C • Not changed from normal driving
P084D • Not changed from normal driving
P0863 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P0890 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed
• Vehicle speed is not increased
P0962 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P0963 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P0965 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed When a malfunction occurs on the low oil pressure side
• Selector shock is large
• Lock-up is not performed When a malfunction occurs on the high oil pressure side
P0966 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P0967 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
P2765 •Start is slow
• Acceleration is slow
• Lock-up is not performed —
DTC Vehicle behavior Conditions of vehicle
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
TM-236
< SYSTEM DESCRIPTION >[CVT: RE0F10E]
SYSTEM
CVT CONTROL SYSTEM : Protection Control
INFOID:0000000009464206
The TCM becomes the protection control status temporar ily to protect the safety when the safety of TCM and
transmission is lost. It automatically returns to the normal status if the safety is secured.
The TCM has the following protection control.
CONTROL FOR WHEEL SPIN
TORQUE IS REDUCED WHEN DRIVING WITH THE REVERSE GEAR
CONTROL WHEN FLUID TEMPERATURE IS HIGH
P2813 • Selector shock is large
•Start is slow
• Acceleration is slow
• Vehicle speed is not increased When a malfunction occurs on the low oil pressure side
• Selector shock is large When a malfunction occurs on the high oil pressure side
P2814 • Selector shock is large —
P2815 • Selector shock is large —
U0073 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
U0100 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
U0140 • Not changed from normal driving —
U0141 • Not changed from normal driving —
U0155 • Not changed from normal driving —
U0300 • Selector shock is large
•Start is slow
• Acceleration is slow
• Lock-up is not performed —
U1000 • Not changed from normal driving — U1117 • Not changed from normal driving — DTC Vehicle behavior Conditions of vehicle
Control
When a wheel spin is detected, the engine output and gear ratio are limited and the line pressure is increased.
Limits engine output when a wheel spin occurs in any of right and left drive wheels.
Vehicle behavior in
control If the accelerator is kept depressing during wheel spin, the engine revolution and vehicle speed are limited to
a certain degree.
Normal retu rn condi-
tion Wheel spin convergence returns the control to the normal control.
Control Engine output is controlled according to a vehicle speed while reversing the vehicle.
Vehicle behavior in
control Power performance may be lowered while reversing the vehicle.
Normal retu rn condi-
tion Torque returns to normal by positioning the selector lever in a range other than “R” position.
Control
When the CVT fluid temperature is high, the gear shift permission maximum revolution and the maximum
torque are reduced than usual to prevent increase of the oil temperature.
Vehicle behavior in
control Power performance may be lowered, compared to normal control.
Normal retu rn condi-
tion The control returns to the normal control when CVT fluid temperature is lowered.
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
SYSTEMTM-237
< SYSTEM DESCRIPTION > [CVT: RE0F10E]
C
EF
G H
I
J
K L
M A
B
TM
N
O P
REVERSE PROHIBIT CONTROL
LINE PRESSURE CONTROL
LINE PRESSURE CONTROL : System DescriptionINFOID:0000000009464207
SYSTEM DIAGRAM
DESCRIPTION
Highly accurate line pressure control (secondary pressure control) reduces friction for improvement of fuel
economy.
Normal Oil Pressure Control
Appropriate line pressure and secondary pressure suitable for driving condition are determined based on the
accelerator pedal position, engine speed, primary pulley (input) speed, secondary pulley (output) speed, vehi-
cle speed, input torque, stop lamp switch signal, transmission range switch signal, lock-up signal, power volt-
age, target shift ratio, oil temperature, oil pressure, and paddle shift (up/down) signal.
Secondary Pressure Feedback Control
In normal oil pressure control and oil pressure control in shifting, highly accurate secondary pressure is deter-
mined by detecting the secondary pressure using an oil pressure sensor and by feedback control.
SHIFT CONTROL
Control The reverse brake is controlled to avoid becoming engaged when the selector lever is set in “R” position while
driving in forward direction at more than the specified speed.
Vehicle behavior in
control If the selector lever is put at “R” position when driving with the forward gear, the gear becomes neutral, not
reverse.
Normal return condi-
tion The control returns to normal control when the vehicle is driven at low speeds. (The reverse brake becomes
engaged.)
JSDIA3716GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
TM-238
< SYSTEM DESCRIPTION >[CVT: RE0F10E]
SYSTEM
SHIFT CONTROL : System Description
INFOID:0000000009464208
SYSTEM DIAGRAM
DESCRIPTION
To select the gear ratio that can give the driving force to meet driver's intent or vehicle situation, the vehicle
driving condition such as vehicle speed or accelera tor pedal position is detected and the most appropriate
gear ratio is selected and the shifting method before reaching the speed is determined. The information is out-
put to the primary pressure solenoid valve and secondary pressure solenoid valve to control the line pressure
input/output to the pulley, to determine the pulley (mov able pulley) position and to control the gear position.
D Position
JSDIA3761GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
TM-240
< SYSTEM DESCRIPTION >[CVT: RE0F10E]
SYSTEM
DESCRIPTION
Based on accelerator pedal angle, engine speed, prim
ary pulley speed, and the input speed, the optimum
operating pressure is set to reduce impact of a selector lever operation while shifting from “N” (“P”) to “D” (“R”)
position.
LOCK-UP CONTROL
LOCK-UP CONTROL : System DescriptionINFOID:0000000009464210
SYSTEM DIAGRAM
JSDIA3711GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
SYSTEMTM-241
< SYSTEM DESCRIPTION > [CVT: RE0F10E]
C
EF
G H
I
J
K L
M A
B
TM
N
O P
DESCRIPTION
• Controls for improvement of the transmission effici ency by engaging the torque converter clutch in the
torque converter and eliminating slip of the converter. Achieves comfortable driving with slip control of the
torque converter clutch.
• The oil pressure feed circuit for the torque converter clutch piston chamber is connected to the torque con-
verter clutch control valve. The torque converter clut ch control valve is switched by the torque converter
clutch solenoid valve with the signal from TCM. This contro ls the oil pressure circuit, which is supplied to the
torque converter clutch piston chamber, to the release side or engagement side.
• If the CVT fluid temperature is low or the vehicle is in fail-safe mode due to malfunction, lock-up control is
prohibited.
Lock-up engagement
In lock-up engagement, the torque converter clutch solenoi d valve makes the torque converter clutch control
valve locked up to generate the lock-up apply pressure. This pushes the torque converter clutch piston for
engagement.
Lock-up release condition
In lock-up release, the torque converter clutch solenoi d valve makes the torque converter clutch control valve
non-locked up to drain the lock-up apply pressure. This does not engage the torque converter clutch piston.
JSDIA3717GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM