2003 NISSAN X-TRAIL clutch

OVERALL SYSTEM
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TCM FunctionECS004QE
The function of the TCM is to:

Receive input signals sent from various switches and sensors.

Determine required line pressure, shifting point, 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 switches and sensors. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM
SWITCHES & SENSORS

TCM

ACTUATORS
PNP switch
Accelerator pedal position (APP)
sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed sensor
Overdrive control switch signal
Stop lamp switch signalShift control
Line pressure control
Lock-up control
Overrun clutch control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
control
CAN systemShift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
O/D OFF indicator lamp
SCIA4505E

AT-34
OVERALL SYSTEM

Input/Output Signal of TCMECS00CTC
*1: Spare for vehicle speed sensor·A/T (revolution sensor)
*2: Spare for accelerator pedal position signal
*3: If these input and output signals are different, the TCM triggers the fail-safe function.
*4: Used as a condition for starting self-diagnostics; if self-diagnostics are not started, it is judged that there is some kind of error.
*5: Input by CAN communications.
*6: Output by CAN communications.
Line Pressure ControlECS004QF

TCM has various line pressure control characteristics to match the driving conditions.

An ON-OFF duty signal is sent to the line pressure solenoid valve based on TCM characteristics.

Hydraulic pressure on the clutch and brake is electronically controlled through the line pressure solenoid
valve to accommodate engine torque. This results in smooth shift operation.
NORMAL CONTROL
The line pressure to throttle opening characteristics is set for suitable
clutch operation.
Control itemLine
pressure
controlVehicle
speed
controlShift
controlLock-up
controlEngine
brake
controlFail-safe
function
(*3)Self-diag-
nostics
function
InputAccelerator pedal position signalXXXXXXX
Vehicle speed sensor A/T
(Revolution sensor)XXXX XX
Vehicle speed sensor MTR
(*1)XXXX X
Closed throttle position signal
(*5)(*2) X (*2) X X (*4) X
Wide open throttle position signal
(*5)(*2) X (*2) X (*4) X
Engine speed signal X X
PNP switch XXXXXX(*4) X
Stop lamp switch signal
(*5)XXX(*4) X
A/T fluid temperature sensors X X X X X
TCM power supply voltage signal XX
Out-
putShift solenoid valve A/B X X X
Line pressure solenoid X X X
Torque converter clutch solenoid
valveXXX
Overrun clutch solenoid valve X X X X
O/D OFF indicator lamp
(*6)X
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OVERALL SYSTEM
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BACK-UP CONTROL (ENGINE BRAKE)
If the selector lever is shifted to “2” position while driving in D4 (OD)
or D
3 , great driving force is applied to the clutch inside the transmis-
sion. Clutch operating pressure (line pressure) must be increased to
deal with this driving force.
DURING SHIFT CHANGE
The line pressure is temporarily reduced corresponding to a change
in engine torque when shifting gears (that is, when the shift solenoid
valve is switched for clutch operation) to reduce shifting shock.
AT LOW FLUID TEMPERATURE

Fluid viscosity and frictional characteristics of the clutch facing change with fluid temperature. Clutch
engaging or band-contacting pressure is compensated for, according to fluid temperature, to stabilize
shifting quality.

The line pressure is reduced below 60°C (140°F) to prevent
shifting shock due to low viscosity of automatic transmission
fluid when temperature is low.

Line pressure is increased to a maximum irrespective of the
throttle opening when fluid temperature drops to −10°C (14°F).
This pressure rise is adopted to prevent a delay in clutch and
brake operation due to extreme drop of fluid viscosity at low
temperature.
Shift ControlECS00CTD
The shift is regulated entirely by electronic control to accommodate vehicle speed and varying engine opera-
tions. This is accomplished by electrical signals transmitted by the revolution sensor and the ECM (accelerator
pedal position sensor). This results in improved acceleration performance and fuel economy.
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AT-36
OVERALL SYSTEM

CONTROL OF SHIFT SOLENOID VALVES A AND B
The TCM activates shift solenoid valves A and B according to sig-
nals from the throttle position sensor and revolution sensor to select
the optimum gear position on the basis of the shift schedule memo-
rized in the TCM.
The shift solenoid valve performs simple ON-OFF operation. When
set to “ON”, the drain circuit closes and pilot pressure is applied to
the shift valve.
RELATION BETWEEN SHIFT SOLENOID VALVES A AND B GEAR POSITIONS
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 drawing 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 ControlECS00CTE
The torque converter clutch piston in the torque converter is locked to eliminate torque converter slip to
increase power transmission efficiency. The solenoid valve is controlled by an ON-OFF duty signal sent from
the TCM. The signal is converted to an oil pressure signal which controls the torque converter clutch piston.
CONDITIONS FOR LOCK-UP OPERATION
When vehicle is driven in 3rd and 4th gear position, vehicle speed and throttle opening are detected. If the
detected values fall within the lock-up zone memorized in the TCM, lock-up is performed.
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Shift solenoid valveGear position
D1 , 21 , 11D2 , 22 , 12D3D4 (OD) N-P
A ON (Closed) OFF (Open) OFF (Open) ON (Closed) ON (Closed)
B ON (Closed) ON (Closed) OFF (Open) OFF (Open) ON (Closed)
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Overdrive control switch ON OFF
Selector lever “D” position
Gear position D
4D3
Vehicle speed sensor More than set value
Throttle position sensor Less than set opening
Closed throttle position switch OFF
A/T fluid temperature sensor More than 40°C (104°F)

OVERALL SYSTEM
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TORQUE CONVERTER CLUTCH SOLENOID VALVE CONTROL
Lock-up 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 applying pressure is drained and the torque converter clutch piston
release pressure is generated.
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 applying pressure is generated and the torque converter clutch piston
release pressure is drained.
In this way, the torque converter clutch piston is pressed and coupled.
SMOOTH LOCK-UP CONTROL
When shifting from the lock-up released state to the lock-up applied state, the current output to the torque con-
verter clutch solenoid is controlled with the TCM. In this way, when shifting to the lock-up applied state, the
torque converter clutch is temporarily set to the half-clutched state to reduce the shock.
Half-Clutched State

The current output from the TCM to the torque converter clutch solenoid is varied to steadily increase the
torque converter clutch solenoid pressure.
In this way, the lock-up applying pressure gradually rises and while the torque converter clutch piston is
put into half-clutched status, the torque converter clutch piston operating pressure is increased and the
coupling is completed smoothly.
Engine Brake Control (Overrun Clutch Control)ECS00CTF
Forward one-way clutch is used to reduce shifting shocks in downshifting operations. This clutch transmits
engine torque to the wheels. However, drive force from the wheels is not transmitted to the engine because
the one-way clutch rotates idle. This means the engine brake is not effective.
The overrun clutch operates when the engine brake is needed.
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AT-38
OVERALL SYSTEM

OVERRUN CLUTCH OPERATING CONDITIONS
OVERRUN CLUTCH SOLENOID VALVE CONTROL
The overrun clutch solenoid valve is operated by an ON-OFF signal
transmitted by the TCM to provide overrun clutch control (engine
brake control).
When this solenoid valve is “ON”, the pilot pressure drain port
closes. When it is “OFF”, the drain port opens.
During the solenoid valve “ON” pilot pressure is applied to the end
face of the overrun clutch control valve.
OVERRUN CLUTCH CONTROL VALVE OPERATION
When the solenoid valve is “ON”, pilot pressure is applied to the
overrun clutch control valve. This pushes up the overrun clutch con-
trol valve. The line pressure is then shut off so that the clutch does
not engage.
When the solenoid valve is “OFF”, pilot pressure is not generated. At
this point, the overrun clutch control valve moves downward by
spring force. As a result, overrun clutch operation pressure is pro-
vided by the overrun clutch reducing valve. This causes the overrun
clutch to engage.
In the 2 and 1 position, the overrun clutch control valve remains
pushed down so that the overrun clutch is engaged at all times.
SCIA5658E
Selector lever position Gear position Throttle opening
“D” position D
1 , D2 , D3 gear position Less than 3/16
“2” position 2
1 , 22 gear position
At any position
“1” position 1
1 , 12 gear position
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OVERALL SYSTEM
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Control ValveECS004QG
FUNCTION OF CONTROL VALVES
Valve name Function
Pressure regulator valve, plug and sleeve
plugRegulates oil discharged from the oil pump to provide optimum line pressure for all driv-
ing conditions.
Pressure modifier valve and sleeve Used as a signal supplementary valve to the pressure regulator valve. Regulates pres-
sure-modifier pressure (signal pressure) which controls optimum line pressure for all
driving conditions.
Pilot valve Regulates line pressure to maintain a constant pilot pressure level which controls lock-up
mechanism, overrun clutch, shift timing.
Accumulator control valve Regulates accumulator back-pressure to pressure suited to driving conditions.
Manual valve Directs line pressure to oil circuits corresponding to select positions.
Hydraulic pressure drains when the shift lever is in Neutral.
Shift valve A Simultaneously switches three oil circuits using output pressure of shift solenoid valve A
to meet driving conditions (vehicle speed, throttle opening, etc.).
Provides automatic downshifting and upshifting (1st → 2nd → 3rd → 4th gears/4th →
3rd → 2nd → 1st gears) in combination with shift valve B.
Shift valve B Simultaneously switches two oil circuits using output pressure of shift solenoid valve B in
relation to driving conditions (vehicle speed, throttle opening, etc.).
Provides automatic downshifting and upshifting (1st → 2nd → 3rd → 4th gears/4th →
3rd → 2nd → 1st gears) in combination with shift valve A.
Overrun clutch control valve Switches hydraulic circuits to prevent engagement of the overrun clutch simultaneously
with application of the brake band in D
4 . (Interlocking occurs if the overrun clutch
engages during D
4 .)
1st reducing valve Reduces low & reverse brake pressure to dampen engine-brake shock when downshift-
ing from the 1st position 1
2 to 11 .
Overrun clutch reducing valve Reduces oil pressure directed to the overrun clutch and prevents engine-brake shock.
In the 1st and 2nd positions, line pressure acts on the overrun clutch reducing valve to
increase the pressure-regulating point, with resultant engine brake capability.
Torque converter relief valve Prevents an excessive rise in torque converter pressure.
Torque converter clutch control valve, plug
and sleeveActivates or inactivates the lock-up function.
Also provides smooth lock-up through transient application and release of the lock-up
system.
1-2 accumulator valve and piston Lessens the shock find when the 2nd gear band servo contracts, and provides smooth
shifting.
3-2 timing valve Switches the pace that oil pressure is released depending on vehicle speed; maximizes
the high clutch release timing, and allows for soft downshifting.
Shuttle valve Determines if the overrun clutch solenoid valve should control the 3-2 timing valve or the
overrun clutch control valve and switches between the two.
Cooler check valve At low speeds and with a small load when a little heat is generated, saves the volume of
cooler flow, and stores the oil pressure for lock-up.

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
AT-45
[EURO-OBD]
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SELF-DIAGNOSTIC PROCEDURE (WITH CONSULT-II)
1. Turn on CONSULT-II and touch “ENGINE” for EURO-OBD
detected items or touch “A/T” for TCM self-diagnosis.
If A/T is not displayed, check TCM power supply and ground cir-
cuit. Refer to AT- 9 4 , "
TCM Terminals and Reference Value" . If
result is NG, refer to PG-2, "
POWER SUPPLY ROUTING" .
2. Touch “SELF DIAGNOSIS”.
Display shows malfunction experienced since the last erasing
operation.
CONSULT-II performs “real time diagnosis”.
Also, any malfunction detected while in this mode will be dis-
played at real time.
SELF-DIAGNOSTIC RESULT TEST MODE
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Items (CONSULT-II screen terms) Malfunction is detected when... EURO-OBD (DTC)
CAN COMM CIRCUIT

Malfunction is detected in CAN communication line. U1000
VHCL SPEED SEN·A/T

TCM does not receive the proper voltage signal from the sensor.P0720
VHCL SPEED SEN·MTR—
THROTTLE POSI SEN

TCM receives an excessively low or high voltage from this sensor P1705
SHIFT SOLENOID/V A

TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.P0750
SHIFT SOLENOID/V B

TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.P0755
OVERRUN CLUTCH S/V

TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.P1760
T/C CLUTCH SOL/V

TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.P0740
ATF TEMP SEN/CIRC

TCM receives an excessively low or high voltage from the sensor.P0710
BATT/FLUID TEMP SEN—
ENGINE SPEED SIG

TCM does not receive the proper voltage signal from the ECM. P0725
A/T 1ST GR FNCTN

A/T cannot be shifted to the 1st gear position even if electrical circuit is
good.P0731*1
A/T 2ND GR FNCTN

A/T cannot be shifted to the 2nd gear position even if electrical circuit is
good.P0732*1
A/T 3RD GR FNCTN

A/T cannot be shifted to the 3rd gear position even if electrical circuit is
good.P0733*1
A/T 4TH GR FNCTN

A/T cannot be shifted to the 4th gear position even if electrical circuit is
good.P0734*1
LINE PRESSURE S/V

TCM detects an improper voltage drop when it tries to operate the sole-
noid valve.P0745
CONTROL UNIT (RAM)

TCM memory (RAM) is malfunctioning —
CONTROL UNIT (ROM)

TCM memory (ROM) is malfunctioning —