2008 NISSAN TIIDA engine control

AT-32
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
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 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)INFOID:0000000001703169
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.
SCIA5623E

A/T CONTROL SYSTEM
AT-33
< SERVICE INFORMATION >
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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. 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.
SCIA7186E
SAT015J
SCIA7172E

AT-34
< SERVICE INFORMATION >
A/T CONTROL SYSTEM
Control Valve
INFOID:0000000001703170
FUNCTION OF CONTROL VALVES
Centrifugal Cancel MechanismINFOID:0000000001703171
FUNCTION
The centrifugal cancel mechanism is a mechanism to cancel the centrifugal hydraulic pressure instead of the
conventional check balls. It cancels the centrifugal hydraulic 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
plugRegulates 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 (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-40
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
●: 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.
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000001703179
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.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with 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. 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 intermittently 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 replacement of good parts.
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●→×–––
“2” position●●1st –●→×●→×–––
×●2nd –●→× ×–––
××3rd – x×–––
“1” position●●1st –●→×●→×–––
×●2nd –●→× ×–––
××3rd – x×–––
SAT631IA

TROUBLE DIAGNOSIS
AT-41
< SERVICE INFORMATION >
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A visual check only, may not find the cause of the malfunctions. A
road test with CONSULT-III or a circuit tester connected should be
performed. Follow the "WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such malfunctions, espe-
cially intermittent ones. Find out what symptoms are present and
under what conditions they occur. A “DIAGNOSTIC WORKSHEET”
like the example ("DIAGNOSTIC WORKSHEET" ) should be used.
Start your diagnosis by looking for “conventional” malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
Also check related Service bulletins for information.
WORK FLOW
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate. In
general, each customer feels differently about a malfunction. It is important to fully understand the symptoms
or conditions for a customer complaint.
Make good use of the two sheets provided, "Information from customer" and "Diagnostic Worksheet Chart" ,
to perform the best troubleshooting possible.
Work Flow Chart
SAT632I
SEF234G

AT-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Line Pressure
Judgement of Line Pressure Test
Road TestINFOID:0000000001703183
DESCRIPTION
• The purpose of the test is to determine overall performance of A/T
and analyze causes of malfunctions.
• The road test consists of the following three parts:
1. Check before engine is started. Refer to AT- 5 3
.
2. Check at idle. Refer to AT- 5 3
.
3. Cruise test
• Inspection all the item from Part 1 to Part 3. Refer to AT- 5 5
,
AT- 5 8
and AT- 5 9 .
Engine speedLine pressure [kPa (kg/cm
2 , psi)]
D, 2nd and 1st positions R position
Idle speed 500 (5.1, 73) 778 (7.9, 113)
Stall speed 1,173 (12.0, 170) 1,825 (18.6, 265)
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”, and “2” positions.
Therefore, fluid leakage exists at or around low and reverse brake circuit.
Refer to AT- 1 9 , "
Shift Mechanism".
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
SAT786A

AT-56
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
3. Push overdrive control switch. (OD OFF indicator lamp is off.)
4. Move selector lever to “P” position.
5. Start engine.
6. Move selector lever to “D” position.
7. Accelerate vehicle by constantly depressing accelerator pedal
half-way.
Read gear position. Refer to AT-73, "
CONSULT-III Func-
tion (A/T)" .
Does vehicle start from D
1 ?
YES >> GO TO 2.
NO >> • Mark the box on the AT-40, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" .
•Go to AT-183, "
Vehicle Cannot Be Started from D1" .
• Continue “Road Test”.
2.CHECK SHIFT-UP (D1 TO D2 )
Check shift-up (D
1 to D2 ).
Specified speed when shifting from D
1 to D2. Refer to AT-61, "Vehicle Speed at Which Gear Shifting Occurs" .
Read gear position, throttle opening and vehicle speed.
Refer to AT-73, "
CONSULT-III Function (A/T)" .
Does A/T shift from D
1 to D2 at the specified speed?
YES >> GO TO 3.
NO >> • Mark the box on the AT-40, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" .
•Go to AT-185, "
A/T Does Not Shift: D1→ D2or Does
Not Kickdown: D4→ D2" .
• Continue “Road Test”.
3.CHECK SHIFT-UP (D2 TO D3 )
Check shift-up (D
2 to D3 ).
Specified speed when shifting from D
2 to D3. Refer to AT-61, "Vehicle Speed at Which Gear Shifting Occurs" .
SCIA5472E
SAT775B
SAT495G
SCIA7188E

AT-58
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
• Continue “Road Test”.
8.CHECK SHIFT-DOWN (D4 TO D3 )
Decelerate vehicle by applying foot brake lightly.
Read gear position and engine speed. Refer to AT-73, "
CON-
SULT-III Function (A/T)" .
Does engine speed return to idle smoothly when A/T is shifted from
D4 to D3 ?
YES >> 1. Stop vehicle.
2. Go to AT-58, "
Cruise Test - Part 2" .
NO >> • Mark the box on the AT-40, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" .
•Go to AT-192, "
Engine Speed Does Not Return to Idle
(Light Braking D4→ D3)" .
• Continue “Road Test”.
Cruise Test - Part 2INFOID:0000000001703187
1.CHECK STARTING GEAR (D1 ) POSITION
1. Push overdrive control switch. (OD OFF indicator lamp is off.)
2. Move selector lever to “D” position.
3. Accelerate vehicle by half throttle again.
Read gear position. Refer to AT-73, "
CONSULT-III Func-
tion (A/T)" .
Does vehicle start from D
1 ?
YES >> GO TO 2.
NO >> • Mark the box on the AT-40, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" .
•Go to AT-183, "
Vehicle Cannot Be Started from D1" .
• Continue “Road Test”.
2.CHECK SHIFT-UP AND SHIFT-DOWN (D3 TO D4 TO D2 )
1. Accelerate vehicle to 80 km/h (50 MPH) as shown in the figure.
2. Release accelerator pedal and then quickly depress it fully.
Read gear position and throttle opening. Refer to AT-73,
"CONSULT-III Function (A/T)" .
Does A/T shift from D
4 to D2 as soon as accelerator pedal is
depressed fully?
YES >> GO TO 3.
NO >> • Mark the box on the AT-40, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" .
•Go to AT-185, "
A/T Does Not Shift: D1→ D2or Does
Not Kickdown: D4→ D2" .
• Continue “Road Test”.
3.CHECK SHIFT-UP (D2 TO D3 )
Check shift-up (D
2 to D3 )
Specified speed when shifting from D
2 to D3 . Refer to AT-61, "Vehicle Speed at Which Gear Shifting Occurs" .
SAT959I
SAT495G
SCIA7192E