2003 NISSAN TEANA ENGINE CONTROL

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.

AT-36
TROUBLE DIAGNOSIS

How to Perform Trouble Diagnoses for Quick and Accurate RepairBCS000ZZ
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelera-
tor pedal position sensor or PNP switch and provides shift control or
lock-up control via A/T solenoid valves.
Input and output signals must always be correct and stable in the
operation of the A/T system. The 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 inter-
mittently rather than continuously. Most intermittent malfunctions are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only, may not find the cause of the malfunctions. A
road test with CONSULT-II or a circuit tester connected should be
performed. Follow the AT- 3 7 , "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a drivability complaint. The customer
can supply good information about such malfunctions, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” like the
example (AT- 3 8 , "
DIAGNOSTIC WORKSHEET" ) should be used.
Start your diagnosis by looking for “conventional” malfunctions first.
This will help troubleshoot drivability malfunctions on an electroni-
cally controlled engine vehicle.
Also check related Service bulletins for information.
SAT631IA
SAT632I
SEF234G

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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5. Start engine and measure line pressure at idle and stall speed.
CAUTION:

Keep the brake pedal pressed all the way down during
measurement.

When measuring line pressure at stall speed, refer to AT-
43, "STALL TEST" .
Line Pressure
Judgement of Line Pressure Test
SAT493G
Engine speed rpmLine pressure kPa (bar, kg/cm2 , psi)
“D”, “3”, “2” and “1” positions “R” position
Idle 500 (5.00, 5.1, 73) 778 (7.78, 7.9, 113)
Stall 1,233 (12.33, 12.6, 179) 1,918 (19.18, 19.6, 278)
Judgement Suspected parts
At idleLine pressure is low in all positions.

Oil pump wear

Control piston damage

Pressure regulator valve or plug sticking

Spring for pressure regulator valve damaged

Fluid pressure leakage between oil strainer and pressure regulator valve

Clogged strainer
Line pressure is low in particular posi-
tion.

Fluid pressure leakage between manual valve and particular clutch

For example, line pressure is:
− Low in “R” and “1” positions, but
− Normal in “D”, “3” and “2” positions.
Therefore, fluid leakage exists at or around low and reverse brake circuit.
Refer to AT-18, "
CLUTCH AND BAND CHART" .
Line pressure is high.

Accelerator pedal position signal malfunction

A/T fluid temperature sensor damaged

Line pressure solenoid valve sticking

Short circuit of line pressure solenoid valve circuit

Pressure modifier valve sticking

Pressure regulator valve or plug sticking

Open in dropping resistor circuit
At stall
speedLine pressure is low.

Accelerator pedal position signal malfunction

Line pressure solenoid valve sticking

Short circuit of line pressure solenoid valve circuit

Pressure regulator valve or plug sticking

Pressure modifier valve sticking

Pilot valve sticking

TROUBLE DIAGNOSIS
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Symptom ChartBCS0010B
Numbers are arranged in order of inspection.
Perform inspections starting with number one and work up.
Items Symptom Condition Diagnostic item Reference page
No Lock-up
Engagement/
TCC InoperativeTorque converter
is not locked up.ON vehicle1. Accelerator pedal position sensor
EC-272
*1, EC-652*2
2. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 8 0, AT- 8 6
3. PNP switchAT- 1 6 1
4. Engine speed signalAT- 11 6
5. A/T fluid temperature sensorAT- 11 0
6. Line pressure testAT- 4 6
7. Torque converter clutch solenoid valveAT- 1 0 5
8. Control valve assemblyAT- 2 2 5
OFF vehicle 9. Torque converterAT- 2 5 5
Torque converter
clutch piston slip.ON vehicle1. A/T fluid levelAT- 1 4
2. Accelerator pedal position sensor
EC-272*1, EC-652*2
3. Line pressure testAT- 4 6
4. Torque converter clutch solenoid valveAT- 1 0 5
5. Line pressure solenoid valveAT- 1 2 6
6. Control valve assemblyAT- 2 2 5
OFF vehicle 7. Torque converterAT- 2 5 5
Lock-up point is
extremely high or
low.ON vehicle1. Accelerator pedal position sensor
EC-272
*1, EC-652*2
2. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 8 0, AT- 8 6
3. Torque converter clutch solenoid valveAT- 1 0 5
4. Control valve assemblyAT- 2 2 5
Shift ShockSharp shock in
shifting from “N”
to “D” position.ON vehicle1. Engine idle speed
EC-45
*1, EC-387*2
2. Accelerator pedal position sensor
EC-272*1, EC-652*2
3. Line pressure testAT- 4 6
4. A/T fluid temperature sensorAT- 11 0
5. Engine speed signalAT- 11 6
6. Line pressure solenoid valveAT- 1 2 6
7. Control valve assemblyAT- 2 2 5
8. N-D accumulatorAT- 2 2 5
OFF vehicle 9. Forward clutchAT- 3 0 7
Too sharp a
shock in change
from D
1 to D2 .ON vehicle1. Accelerator pedal position sensor
EC-272
*1, EC-652*2
2. Line pressure testAT- 4 6
3. Accumulator servo releaseAT- 2 2 5
4. Control valve assemblyAT- 2 2 5
5. A/T fluid temperature sensorAT- 11 0
OFF vehicle 6. Brake bandAT- 3 2 9