2003 NISSAN TEANA torque

AT-28
A/T CONTROL SYSTEM

Line Pressure ControlBCS000ZS

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 characteristics of line pressure to throttle opening.
BACK-UP CONTROL (ENGINE BRAKE)
If the selector lever is shifted to “2” position while driving in D4 , D3
or 33 , 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.
SCIA4826E
SCIA4827E
SCIA4828E

AT-30
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 ControlBCS000ZU
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.
TORQUE CONVERTER CLUTCH SOLENOID VALVE CONTROL
Lock-up Control System Diagram
SAT009J
Selector lever “D” position “3” position
Gear position D
4 , D333
Vehicle speed sensor More than set value
accelerator pedal position sensor Less than set opening
Closed throttle position signal OFF
A/T fluid temperature sensor More than 20°C (68°F)
SCIA5623E

A/T CONTROL SYSTEM
AT-31
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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 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 applying pressure is increased and the coupling is
completed smoothly.
Engine Brake Control (Overrun Clutch Control)BCS000ZV
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.
OVERRUN CLUTCH OPERATING CONDITIONS
SCIA4831E
Selector lever position Gear position Throttle opening
“D” position D
1 , D2 , D3 gear position
Less than 3/16
“3” position 3
1 , 32 , 33 gear position
“2” position 2
1 , 22 gear position
At any position
“1” position 1
1 , 12 gear position

A/T CONTROL SYSTEM
AT-33
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Control ValveBCS000ZW
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.

TROUBLE DIAGNOSIS
AT-35
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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.

: Solenoid ON
×: Solenoid OFF
–: Non-standard condition
Line Pressure Solenoid Valve
If non-standard solenoid signal is sent to TCM, line pressure 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 converter clutch solenoid valve is turned OFF to release
lock-up.
Overrun Clutch Solenoid Valve
If non-standard solenoid signal is sent to TCM, overrun clutch solenoid valve is turned OFF to engage overrun
clutch. This will result in more effective engine brake during deceleration.
Shift positionNormalMalfunction in solenoid
valve AMalfunction in solenoid
valve BMalfunction in solenoid
valves A and B
A B Gear A B Gear A B Gear A B Gear
“D” position

1st –
→×
3rd
→×–
3rd ––
3rd ×
2nd –
→× ×–––
××3rd – x×–––

×4th – x
→×–––
“3” position

1st –
→×
→×–––
×
2nd –
→× ×–––
××3rd – x×–––
“2” position

1st –
→×
→×–––
×
2nd –
→× ×–––
××3rd – x×–––
“1” position

1st –
→×
→×–––
×
2nd –
→× ×–––
××3rd – x×–––

TROUBLE DIAGNOSIS
AT-39
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Diagnostic Worksheet
1.❏ Read the Fail-safe and listen to customer complaints.AT- 3 4, AT- 3 8
2.❏ Check A/T fluidAT- 1 4❏ Leakage (Follow specified procedure)
❏ Fluid condition
❏ Fluid level
3.❏ Perform “STALL TEST” and “LINE PRESSURE TEST”.AT- 4 3
,
AT- 4 6
❏ “STALL TEST” — Mark possible damaged components/others.
❏ Torque converter one-way clutch
❏ Reverse clutch
❏ Forward clutch
❏ Overrun clutch
❏ Forward one-way clutch❏ Low & reverse brake
❏ Low one-way clutch
❏ Engine
❏ Line pressure is low
❏ Clutches and brakes except high clutch and
brake band are OK
❏ “LINE PRESSURE TEST” — Suspected parts:
4.❏ Perform “Road Test”.AT- 4 8
4-1.“Check Before Engine is Started”AT- 4 8
❏ AT-173, "A/T CHECK Indicator Lamp Does Not Come On" .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 6 9
, AT- 7 6 .
❏ AT-133, "
CAN COMMUNICATION LINE" .
❏ AT-80, "
VEHICLE SPEED SENSOR·A/T (REVOLUTION SENSOR)" .
❏ AT-86, "
VEHICLE SPEED SENSOR MTR" .
❏ AT-120, "
TURBINE REVOLUTION SENSOR" .
❏ AT-90, "
SHIFT SOLENOID VALVE A" .
❏ AT-95, "
SHIFT SOLENOID VALVE B" .
❏ AT-100, "
OVERRUN CLUTCH SOLENOID VALVE" .
❏ AT-105, "
TORQUE CONVERTER CLUTCH SOLENOID VALVE" .
❏ AT-110, "
BATT/FLUID TEMP SEN (A/T FLUID TEMP SENSOR CIRCUIT AND TCM POWER
SOURCE)" .
❏ AT-116, "
ENGINE SPEED SIGNAL" .
❏ AT-136, "
A/T 1ST GEAR FUNCTION" .
❏ AT-140, "
A/T 2ND GEAR FUNCTION" .
❏ AT-143, "
A/T 3RD GEAR FUNCTION" .
❏ AT-146, "
A/T 4TH GEAR FUNCTION" .
❏ AT-151, "
A/T TCC S/V FUNCTION (LOCK-UP)" .
❏ AT-126, "
LINE PRESSURE SOLENOID VALVE" .
❏ AT-156, "
CONTROL UNIT (RAM)" .
❏ AT-157, "
CONTROL UNIT (ROM)" .
4-2.“Check at Idle”AT- 4 8
❏ AT-175, "Engine Cannot Be Started in “P” and “N” Position" .
❏ AT-176, "
In “P” Position, Vehicle Moves Forward or Backward When Pushed" .
❏ AT-176, "
In “N” Position, Vehicle Moves" .
❏ AT-177, "
Large Shock. “N” → “R” Position" .
❏ AT-179, "
Vehicle Does Not Creep Backward in “R” Position" .
❏ AT-181, "
Vehicle Does Not Creep Forward in “D”, “3”, “2” or “1” Position" .

AT-40
TROUBLE DIAGNOSIS

4. 4-3.“Cruise Test”AT- 5 0
Part 1
❏ AT-182, "
Vehicle Cannot Be Started From D1" .
❏ AT-184, "
A/T Does Not Shift: D1 → D2 or Does Not Kickdown: D4 → D2" .
❏ AT-186, "
A/T Does Not Shift: D2 → D3" .
❏ AT-188, "
A/T Does Not Shift: D3 → D4" .
❏ AT-191, "
A/T Does Not Perform Lock-up" .
❏ AT-193, "
A/T Does Not Hold Lock-up Condition" .
❏ AT-195, "
Lock-up Is Not Released" .
❏ AT-195, "
Engine Speed Does Not Return To Idle (Light Braking D4 → D3 )" .
Part 2AT- 5 1
❏ AT-182, "Vehicle Cannot Be Started From D1" .
❏ AT- 1 8 4 , "
A/T Does Not Shift: D1 → D2 or Does Not Kickdown: D4 → D2" .
❏ AT-186, "
A/T Does Not Shift: D2 → D3" .
❏ AT-188, "
A/T Does Not Shift: D3 → D4" .
Part 3AT- 5 2
❏ AT-197, "A/T Does Not Shift: D4 → 33 , When A/T Selector Lever “D” → “3”" .
❏ AT-203, "
Vehicle Does Not Decelerate By Engine Brake (D4 → 33 )" .
❏ AT-198, "
A/T Does Not Shift: 33 → 22 , When Selector Lever “3” → “2” Position" .
❏ AT-205, "
Vehicle Does Not Decelerate By Engine Brake (33 → 22 )" .
❏ AT-200, "
A/T Does Not Shift: 22 → 11 , When Selector Lever “2” → “1” Position" .
❏ AT-208, "
Vehicle Does Not Decelerate By Engine Brake (22 → 11 )" .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 6 9
, AT- 7 6 .
❏ AT-133, "
CAN COMMUNICATION LINE" .
❏ AT-80, "
VEHICLE SPEED SENSOR·A/T (REVOLUTION SENSOR)" .
❏ AT-86, "
VEHICLE SPEED SENSOR MTR" .
❏ AT-120, "
TURBINE REVOLUTION SENSOR" .
❏ AT-90, "
SHIFT SOLENOID VALVE A" .
❏ AT-95, "
SHIFT SOLENOID VALVE B" .
❏ AT-100, "
OVERRUN CLUTCH SOLENOID VALVE" .
❏ AT-105, "
TORQUE CONVERTER CLUTCH SOLENOID VALVE" .
❏ AT-110, "
BATT/FLUID TEMP SEN (A/T FLUID TEMP SENSOR CIRCUIT AND TCM POWER
SOURCE)" .
❏ AT-116, "
ENGINE SPEED SIGNAL" .
❏ AT-136, "
A/T 1ST GEAR FUNCTION" .
❏ AT-140, "
A/T 2ND GEAR FUNCTION" .
❏ AT-143, "
A/T 3RD GEAR FUNCTION" .
❏ AT-146, "
A/T 4TH GEAR FUNCTION" .
❏ AT-151, "
A/T TCC S/V FUNCTION (LOCK-UP)" .
❏ AT-126, "
LINE PRESSURE SOLENOID VALVE" .
❏ AT-156, "
CONTROL UNIT (RAM)" .
❏ AT-157, "
CONTROL UNIT (ROM)" .
5.❏ For self-diagnosis NG items, inspect each component. Repair or replace the damaged parts.
6.❏ Perform “Road Test”.AT- 4 8
7.❏ Perform the Diagnostic Procedures for all remaining items marked NG. Repair or replace the damaged parts.
Refer to the Symptom Chart when you perform the procedures. (The chart also shows some other possible
symptoms and the component inspection orders.)AT- 5 5
8.❏ Erase DTC from TCM and ECM memories.AT- 6 9AT- 7 9

AT-44
TROUBLE DIAGNOSIS

6. Accelerate to wide open throttle gradually while applying foot
brake.
7. Quickly note the engine stall revolution and immediately release
throttle.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
8. Move selector lever to “N” position.
9. Cool off ATF.
CAUTION:
Run engine at idle for at leas 1 minute.
10. Repeat steps 6 through 9 with selector lever in “3”, “2”, “1” and
“R” positions.
Judgement of Stall Test
The test result and possible damaged components relating to each result are shown in the illustrations on next
page.
In order to pinpoint the possible damaged components, refer to AT- 3 7 , "
Work Flow Chart" .
NOTE:
Stall revolution is too high in “D”, “3”, “2”, or “1” position:

Slippage occurs in 1st gear but not in 2nd and 3rd gears. ..... Low one-way clutch slippage

Slippage occurs in the following gears:
1st through 3rd gears in “D” position and engine brake functions with selector lever set to “3” position.
1st and 2nd gears in “2” position and engine brake functions with accelerator pedal released (fully closed
throttle)...... Forward clutch or forward one-way clutch slippage
Stall revolution is too high in “R” position:

Engine brake does not function in “1” position. ..... Low & reverse brake slippage

Engine brake functions in “1” position. ..... Reverse clutch slippage
Stall revolution within specifications:

Vehicle does not achieve speed of more than 80 km/h (50 MPH). ..... One-way clutch seizure in torque
converter housing
CAUTION:
Be careful since automatic fluid temperature increases abnormally.

Slippage occurs in 3rd and 4th gears in “D” position. ..... High clutch slippage

Slippage occurs in 2nd and 4th gear in “D” position. ..... Brake band slippage

Engine brake does not function in 2nd and 3rd gears in “D” position with 3rd position switch set to ON, 2nd
gear in “2” position, and 1st gear in “1” position. ..... Overrun clutch slippage
Stall revolution less than specifications:

Poor acceleration during starts. ..... One-way clutch seizure in torque converterStall revolution
For QR20DE engine models:
2,400 - 2,850 rpm
For VQ23DE engine models:
2,400 - 2,900 rpm
SAT514G
SCIA5704E