2003 NISSAN TEANA brake

A/T CONTROL SYSTEM
AT-29
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AT LOW FLUID TEMPERATURE

A/T fluid viscosity and frictional characteristics of the 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
shifting shock due to low viscosity of A/T fluid when temperature
is low.

Line pressure is increased to a maximum irrespective of the
throttle 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 temperature.
Shift ControlBCS000ZT
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.
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 revolution sen-
sor 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
SCIA4829E
SCIA4830E
SAT008J
Gear position 1 2 3 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)

A/T CONTROL SYSTEM
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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

AT-32
A/T CONTROL SYSTEM

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” positions, the overrun clutch control valve remains
pushed down so that the overrun clutch is engaged at all times.
SAT015J
SCIA3458E

A/T CONTROL SYSTEM
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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
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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
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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

TROUBLE DIAGNOSIS
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Inspections Before Trouble DiagnosisBCS00102
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check
Inspect for A/T fluid leakage and check the A/T fluid level. Refer to AT- 1 4 , "Checking A/T Fluid" .
A/T Fluid Condition Check
Inspect the A/T fluid condition.
STALL TEST
Stall Test Procedure
1. Check ATF and engine oil levels. If necessary, add ATF and oil.
2. Drive vehicle for approximately 10 minutes or until ATF and
engine oil reach operating temperature.
3. Set parking brake and block wheels.
4. Install a tachometer where it can be seen by driver during test.

It is good practice to mark the point of specified engine
rpm on indicator.
5. Start engine, apply foot brake, and place selector lever in “D”
position.
Fluid status Conceivable Cause Required Operation
Varnished (viscous
varnish state)Clutch, brake
scorchedReplace the ATF and check the A/T
main unit and the vehicle for mal-
functions (wire harnesses, cooler
pipes, etc.)
Milky white or
cloudyWater in the ATFReplace the ATF and check for
places where water is getting in.
Large amount of
metal powder mixed
inUnusual wear of
sliding parts within
A/TReplace the ATF and check for
improper operation of the A/T.
SAT638A
ATF operating temperature: 50 - 80°C (122 - 176°F)
SAT647B
SCIA7463E
SCIA5703E