2010 NISSAN TIIDA Clutch System

A/T CONTROL SYSTEMAT-33
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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
• A/T fluid viscosity and frictional characteristics of t he clutch facing change with A/T fluid temperature. Clutch
engaging or band-contacting pressure is compensated for, according to A/T fluid temperature, to stabilize
shifting quality.
• The line pressure is reduced below 60 °C (140° F) to prevent shift-
ing shock due to high viscosity of A/T fluid when temperature is
low.
• Line pressure is increased to a maximum irrespective of the throt- tle opening when A/T 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 A/T fluid viscosity at low temper-
ature.
Shift ControlINFOID:0000000005397225
The shift is regulated entirely by electronic cont rol to accommodate vehicle speed and varying engine opera-
tions. This is accomplished by electrical signals trans mitted by the output speed sensor and the ECM (acceler-
ator pedal position sensor). This results in improved acceleration performance and fuel economy.
CONTROL OF SHIFT SOLENOID VALVES A AND B
The TCM activates shift solenoid valves A and B according to sig-
nals from the accelerator pedal position sensor and output speed
sensor to select the optimum gear position on the basis of the shift
schedule memorized 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 AND GEAR POSITIONS
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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)
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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)
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A/T CONTROL SYSTEMAT-35
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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 drain-
ing the torque converter clutch piston applying pressure and the torque converter clutch piston release pres-
sure 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 generating
the torque converter clutch piston applying pressure and t he 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 converte r 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 applying pressure is increased and the coupling is
completed smoothly.
Engine Brake Control (Overrun Clutch Control)INFOID:0000000005397227
Forward one-way clutch is used to reduce shifting shoc ks in downshifting operations. This clutch transmits
engine torque to the wheels. However, drive force fr om 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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A/T CONTROL 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 t hen shut off so that the clutch does
not engage. Only in “1” position, however, 1 range pressure is
applied to overrun clutch control valve, resulting in valve moving
downward and clutch engaged.
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. At overrun clutch reduc-
ing valve in “D” position, the hydraulic pressure is reduced to a level
that balances the spring force. This is sent to overrun clutch control
valve and becomes the operating pressure of overrun clutch which is
engaged at all times. In “2” position and “1” position, overrun clutch
reducing valve is pushed down by 2 range pressure. Line pressure is
directly sent to overrun clutch control valve and becomes the operat-
ing pressure of overrun clutch which is engaged at all times.
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A/T CONTROL SYSTEMAT-37
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Control ValveINFOID:0000000005397228
FUNCTION OF CONTROL VALVES
Centrifugal Cancel MechanismINFOID:0000000005397229
FUNCTION
The centrifugal cancel mechanism is a mechanism to c ancel the centrifugal hydraulic pressure instead of the
conventional check balls. It cancels the centrifugal hy draulic pressure which is generated as high clutch drum
rotates, and it allows for preventing high clutch from dragging and for providing stable high clutch piston press-
ing force in all revolution speeds.
STRUCTURE/OPERATION
Valve name Function
Pressure regulator valve, plug and sleeve
plug Regulates oil discharged from the oil pump to provide optimum line pressure for all driving
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 driv-
ing 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 (1GR → 2GR → 3GR → 4GR/4GR →
3GR → 2GR → 1GR) 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 (1GR → 2GR → 3GR → 4GR/4GR →
3GR → 2GR → 1GR) 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 sleeve Activates 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 2GR band servo contracts, and provides smooth shift-
ing.
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.
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AT-38
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A/T CONTROL SYSTEM
A centrifugal cancel housing is provided to cancel the clutch housing pressure. The centrifugal cancel housing
is always filled with ATF from the dedicated fluid passage of oil pump.
When Clutch Pressure Is Not Applied
As high clutch drum rotates, a centrifugal force applies to the remaining ATF in clutch housing to push high
clutch piston. However, on the other hand, the centrifugal force also applies to ATF filled in centrifugal cancel
housing, resulting in a force that pushes high clutch piston back. Consequently the high clutch piston does not
move because both forces cancel each other, and thus high clutch is prevented from dragging.
When Clutch Pressure Is Applied
Clutch pressure that applies to clutch housing overcomes the fluid pressure and spring force of the opposing
centrifugal housing to push high clutch piston, and high clutch is engaged. At this time, the centrifugal force
caused by the revolution speed of high clutch drum has no impact any more since the centrifugal force that
applies to the clutch pressure of clutch housing is canceled by the centrifugal force that applies to centrifugal
cancel housing. As a result, high clutch piston pressing force is always stable in all revolution speeds, and
thus smooth shifting characteristics are achieved.
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TROUBLE DIAGNOSISAT-43
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z : Solenoid ON
× : Solenoid OFF
–: Non-standard condition
Line Pressure Solenoid Valve
If non-standard solenoid signal is sent to TCM, line pre ssure solenoid valve is turned OFF to achieve maxi-
mum oil pressure.
Torque Converter Clutch Solenoid Valve
If non-standard solenoid signal is sent to TCM, torque conv erter clutch solenoid valve is turned OFF to release
lock-up.
Overrun Clutch Solenoid Valve
If non-standard solenoid signal is sent to TCM, overr un clutch solenoid valve is turned OFF to engage overrun
clutch. This will result in more effective engine brake during deceleration.
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000005397237
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelera-
tor pedal position sensor or transmission range switch and provides
shift control or lock-up control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used wit h the OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. T he A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a malfunction that occurs intermittently rather than continuously. Most
intermittent malfunctions are caused by poor electric c onnections or improper wiring. In this case, careful
checking of suspected circuits may hel p prevent the replacement of good parts.
Shift positionNormal
Malfunction in solenoid
valve A Malfunction in solenoid
valve B Malfunction in solenoid
valves A and B
A BGearABGearABGearABGear
“D” position zz
1st –z→×
3rd z
→× –
3rd ––
3rd
×
z2nd – z→× ×–––
×× 3rd – x ×–––
z ×4th – x z→× –––
“2” position zz
1st –z→× z→× –––
× z2nd – z→× ×–––
×× 3rd – x ×–––
“1” position zz
1st –z→× z→× –––
× z2nd – z→× ×–––
×× 3rd – x ×–––
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TROUBLE DIAGNOSIS
Diagnosis Procedure without CONSULT-III
INFOID:0000000005397252
TCM SELF-DIAGNOSTIC PROCEDURE
Description
If a malfunction occurs in electrical system, turning ignition switch ON will illuminate OD OFF indicator lamp for
2 seconds. To detect a malfunction, entering a self-diagnosis start signal retrieves information on malfunctions
from memory and indicates malfunction by blinking OD OFF indicator lamp.
Diagnostic Procedure
1.CHECK OD OFF INDICATOR LAMP
1. Park vehicle on flat surface.
2. Move selector lever to “P” position.
3. Turn ignition switch OFF. Wait at least 5 seconds.
DTC work support item Description Check item
1ST GR FNCTN P0731 Following items for “1GR incorrect ratio (P0731)” can be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnostic results (OK or NG) • Shift solenoid valve A
• Shift solenoid valve B
• Each clutch
•Hydraulic co
ntrol circuit
2ND GR FNCTN P0732 Following items for “2GR incorrect ratio (P0732)” can be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnostic results (OK or NG) • Shift solenoid valve B
• Each clutch
•Hydraulic co
ntrol circuit
3RD GR FNCTN P0733 Following items for “3GR incorrect ratio (P0733)” can be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnostic results (OK or NG) • Shift solenoid valve A
• Each clutch
•Hydraulic co
ntrol circuit
4TH GR FNCTN P0734 Following items for “4GR incorrect ratio (P0734)” can be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnostic results (OK or NG) • Shift solenoid valve A
• Shift solenoid valve B
• Overrun clutch solenoid valve
• Line pressure solenoid valve
• Each clutch
•Hydraulic co
ntrol circuit
TCC S/V FNCTN P0744 Following items for “Torque converter (P0744)” can be confirmed.
• Self-diagnosis status (whether the diagnosis is being performed
or not)
• Self-diagnostic results (OK or NG) • Torque converter clutch sole-
noid valve
• Each clutch
•Hydraulic co ntrol circuit
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