control INFINITI M35 2007 Factory Workshop Manual

A/T CONTROL SYSTEM
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Revision: 2007 April2007 M35/M45
SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
Shift Change System Diagram
*1: Full phase real-time feedback control monitors movement of gear ratio at gear change, and controls oil
pressure at real-time to achieve the best gear ratio.
BLIPPING CONTROL
This system makes transmission clutch engage readily by controlling (synchronizing) engine revolution
according to the (calculation of) engine revolution after shifting down.

“BLIPPING CONTROL” functions.
–When downshifting by accelerator pedal depression at “D” position.
–When downshifting under the manual mode.

TCM selects “BLIPPING CONTROL” or “NORMAL SHIFT CONTROL” according to the gear position, the
select lever position, the engine torque and the speed when accelerating by pedal depression.

Revolution control demand signal is transmitted from TCM to ECM under “BLIPPING CONTROL”.

TCM synchronizes engine revolution according to the revolution control demand signal.
PCIA0013E

AT-36
A/T CONTROL SYSTEM
Revision: 2007 April2007 M35/M45
Shift Change System Diagram
ASC (ADOPTIVE SHIFT CONTROL)
ASC automatically shifts or hold at the 3rd or 4th gear on certain roads (up/down slope and curve) and driving
condition.
When Driving on an Up/Down Slope

ASC judges up/down slope according to the angle of accelerator pedal and vehicle speed. Holding gear at
the 3rd or 4th on an up-slope prevents shift hunting and controls the vehicle to gain maximum driving
force. On a down-slope, automatic shift-down to the 3rd or 4th gear controls to gain maximum engine
brake.
When Driving on a Curve

TCM receives side G sensor signal from ABS actuator and electric unit (control unit). Holding gear at the
3rd or 4th based on the signal prevents shift-up and kick-down and controls to drive smoothly.
SCIA6483E
SCIA6469E

A/T CONTROL SYSTEM
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Lock-up ControlNCS001JU
The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to
increase power transmission efficiency.
The torque converter clutch control valve operation is controlled by the torque converter clutch solenoid valve,
which is controlled by a signal from TCM, and the torque converter clutch control valve engages or releases
the torque converter clutch piston.
Lock-up operation condition table
TORQUE CONVERTER CLUTCH CONTROL VALVE CONTROL
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 the
torque converter clutch solenoid and the lock-up apply pressure is drained.
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 the
torque converter clutch solenoid and lock-up apply pressure is generated.
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 apply pressure gradually rises and while the torque converter clutch piston is put
into half-clutched status, the torque converter clutch piston operating pressure is increased and the cou-
pling is completed smoothly.
Slip Lock-up Control

In the slip region, the torque converter clutch solenoid current is controlled with the TCM to put it into the
half-clutched state. This absorbs the engine torque fluctuation and lock-up operates from low speed.
This raises the fuel efficiency for 3rd, 4th and 5th gears at both low speed and when the accelerator has a
low degree of opening.
Selector lever “D” position “M” position
Gear position 5 4 3 5 4
Lock-up×––××
Slip lock-up×××––
PCIA0014E

AT-38
A/T CONTROL SYSTEM
Revision: 2007 April2007 M35/M45
Engine Brake ControlNCS001JV

The forward one-way clutch transmits the drive force from the engine to the rear wheels. But the reverse
drive from the rear wheels is not transmitted to the engine because the one-way clutch is idling.
Therefore, the low coast brake solenoid is operated to prevent the forward one-way clutch from idling and
the engine brake is operated in the same manner as conventionally.

The operation of the low coast brake solenoid switches the low coast brake switching valve and controls
the coupling and releasing of the low coast brake.
The low coast brake reducing valve controls the low coast brake coupling force.
Control ValveNCS001JW
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valveIn order to prevent the pressure supplied to the torque converter from being excessive,
the line pressure is adjusted to the optimum pressure (torque converter operating pres-
sure).
Pressure regulator valve
Pressure regulator plug
Pressure regulator sleeveAdjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valveWhen the front brake is coupled, adjusts the line pressure to the optimum pressure
(front brake pressure) and supplies it to the front brake. (In 1st, 2nd, 3rd, and 5th gears,
adjusts the clutch pressure.)
Accumulator control valveAdjusts the pressure (accumulator control pressure) acting on the accumulator piston
and low coast reducing valve to the pressure appropriate to the driving state.
Pilot valve AAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve BAdjusts the line pressure and produces the constant pressure (pilot pressure) required
for shift change control.
Low coast brake switching valve During engine braking, supplies the line pressure to the low coast brake reducing valve.
Low coast brake reducing valveWhen the low coast brake is coupled, adjusts the line pressure to the optimum pressure
(low coast brake pressure) and supplies it to the low coast brake.
N-R accumulator Produces the stabilizing pressure for when N-R is selected.
Direct clutch piston switching valve Operates in 4th gear and switches the direct clutch coupling capacity.
High and low reverse clutch control valveWhen the high and low reverse clutch is coupled, adjusts the line pressure to the opti-
mum pressure (high and low reverse clutch pressure) and supplies it to the high and low
reverse clutch. (In 1st, 3rd, 4th and 5th gears, adjusts the clutch pressure.)

A/T CONTROL SYSTEM
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FUNCTION OF PRESSURE SWITCH
Input clutch control valveWhen the input clutch is coupled, adjusts the line pressure to the optimum pressure
(input clutch pressure) and supplies it to the input clutch. (In 4th and 5th gears, adjusts
the clutch pressure.)
Direct clutch control valveWhen the direct clutch is coupled, adjusts the line pressure to the optimum pressure
(direct clutch pressure) and supplies it to the direct clutch. (In 2nd, 3rd, and 4th gears,
adjusts the clutch pressure.)
TCC control valve
TCC control plug
TCC control sleeveSwitches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valveOperates during lock-up to switch the torque converter, cooling, and lubrication system
oil passage.
Cool bypass valve Allows excess oil to bypass cooler circuit without being fed into it.
Line pressure relief valve Discharges excess oil from line pressure circuit.
N-D accumulator Produces the stabilizing pressure for when N-D is selected.
Manual valveSends line pressure to each circuit according to the select position. The circuits to which
the line pressure is not sent drain. Name Function
Name Function
ATF pressure switch 1 (FR/B)Detects any malfunction in the front brake hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 2 (LC/B)Detects any malfunction in the low coast brake hydraulic pressure. When it detects any
malfunction, it puts the system into fail-safe mode.
ATF pressure switch 3 (I/C)Detects any malfunction in the input clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 5 (D/C)Detects any malfunction in the direct clutch hydraulic pressure. When it detects any mal-
function, it puts the system into fail-safe mode.
ATF pressure switch 6 (HLR/C)Detects any malfunction in the high and low reverse clutch hydraulic pressure. When it
detects any malfunction, it puts the system into fail-safe mode.

AT-44
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartNCS001K2
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC “U1000” is displayed with other DTC, first perform the trouble diagnosis for “DTC U1000 CAN
COMMUNICATION LINE”. Refer to AT- 1 0 5
.
Fail-safeNCS001K3
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is an error in a
main electronic control input/output signal circuit.
In fail-safe mode, even if the selector lever is “D” or “M” mode, the A/T is fixed in 2nd, 4th and 5th (depending
on the breakdown position), so the customer should feel “slipping” or “poor acceleration”.
Even when the electronic circuits are normal, under special conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping the tire rotation), the A/T can go into fail-safe mode. If
this happens, switch OFF the ignition switch for 10 seconds, then switch it ON again to return to the normal
shift pattern. Therefore, the customer's vehicle has returned to normal, so handle according to the “WORK
FLOW” (Refer to AT- 4 7
).
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the A/T to mark driving possible.
Vehicle Speed Sensor

Signals are input from two systems - from vehicle speed sensor A/T (revolution sensor) installed on the A/
T and from combination meter so normal driving is possible even if there is a malfunction in one of the
systems. And if vehicle speed sensor A/T (revolution sensor) has unusual cases, 5th gear and manual
mode are prohibited.
Accelerator Pedal Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the engine speed is fixed by ECM to a pre-determined engine speed to make driving possible.
Throttle Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the accelerator opening angle is controlled by the idle signal sent from the ECM which is based
on input indicating either idle condition or off-idle condition (pre-determined accelerator opening) in order
to make driving possible.
PNP Switch

In the unlikely event that a malfunction signal enters the TCM, the position indicator is switched OFF, the
starter relay is switched OFF (starter starting is disabled), the back-up lamp relay switched OFF (back-up
lamp is OFF) and the position is fixed to the “D” position to make driving possible.
Starter Relay

The starter relay is switched OFF. (Starter starting is disabled.)
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

TROUBLE DIAGNOSIS
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Revision: 2007 April2007 M35/M45
A/T Interlock

If there is an A/T interlock judgment malfunction, the A/T is fixed in 2nd gear to make driving possible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine revolution sensor malfunction.

When the coupling pattern below is detected, the fail-safe action corresponding to the pattern is per-
formed.
A/T INTERLOCK COUPLING PATTERN TABLE

: NG X: OK
A/T 1st Engine Braking

When there is an A/T first gear engine brake judgment malfunction, the low coast brake solenoid is
switched OFF to avoid the engine brake operation.
Line Pressure Solenoid

The solenoid is switched OFF and the line pressure is set to the maximum hydraulic pressure to make
driving possible.
Torque Converter Clutch Solenoid

The solenoid is switched OFF to release the lock-up.
Low Coast Brake Solenoid

When a malfunction (electrical or functional) occurs, in order to make driving possible. If the solenoid is
ON, the A/T is held in 2nd gear. If the solenoid is OFF, the A/T is held in 4th gear. (Engine brake is not
applied in 1st and 2nd gear.)
Input Clutch Solenoid

If a malfunction (electrical or functional) occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Direct Clutch Solenoid

If a malfunction (electrical or functional) occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Front Brake Solenoid

If a malfunction (electrical or functional) occurs with the solenoid ON, in order to make driving possible.
The A/T is held in 5th gear. If the solenoid is OFF, the A/T is 4th gear.
High and Low Reverse Clutch Solenoid

If a (electrical or functional) malfunction occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Turbine Revolution Sensor 1 or 2

The control is the same as if there were no turbine revolution sensors, 5th gear and manual mode are pro-
hibited.
Gear positionATF pressure switch output
Fail-safe
functionClutch pressure output pattern after fail-safe func-
tion
SW3
(I/C)SW6
(HLR/
C)SW5
(D/C)SW1
(FR/B)SW2
(LC/B)I/C HLR/C D/C FR/B LC/B L/U
A/T inter-
lock cou-
pling pattern3rd – X X –
Held in
2nd gearOFF OFF ON OFF OFF OFF
4th – X X –
Held in
2nd gearOFF OFF ON OFF OFF OFF
5th X X – X
Held in
2nd gearOFF OFF ON OFF OFF OFF

AT-46
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
How to Perform Trouble Diagnosis for Quick and Accurate RepairNCS001K4
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelera-
tor pedal position sensor (throttle 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 error that occurs intermittently
rather than continuously. Most intermittent errors are caused by poor
electric connections or improper wiring. In this case, careful check-
ing of suspected circuits may help prevent the replacement of good
parts.
A visual check only may not find the cause of the errors. A road test
with CONSULT-II (or GST) or a circuit tester connected should be
performed. Follow the AT- 4 7 , "
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 errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” as
shown on the example (Refer to AT- 4 8
) should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
SAT631IB
SAT632I
SEF234G

AT-64
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
AW D M OD E LS

At closed throttle, the accelerator opening is less than 1/8 condition. (Closed throttle position signal: OFF)

At half throttle, the accelerator opening is 4/8 of the full opening.
Symptom ChartNCS001KF

The diagnostics item numbers show the sequence for inspection. Inspect in order from item 1.

Overhaul and inspection inside the A/T only if A/T fluid condition is NG. Refer to AT- 5 3 , "A/T Fluid Condi-
tion Check" .
Engine model VQ35DE
Throttle positionVehicle speed km/h (MPH)
Lock-up ON Lock-up OFF
Closed throttle 51 - 59 (32 - 37) 48 - 56 (30 - 35)
Half throttle 188 - 196 (117 - 122) 132 - 140 (82 - 87)
No. Item Symptom Condition Diagnostic ItemReference
page
1Shift
ShockLarge shock. (“N” →
“D” position)
Refer to AT-193,
"Large Shock (“N” to
“D” Position)" .ON vehicle1. Engine idle speedEC-83
(for
VQ35DE
engine),
EC-785

(for
VK45DE
engine)
2. Engine speed signalAT- 1 2 4
3. Accelerator pedal position sensorAT- 1 3 2
4. A/T positionAT- 2 2 7
5. A/T fluid temperature sensorAT- 1 3 5
6. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2,
AT- 1 5 1
7. CAN communication lineAT- 1 0 5
8. A/T fluid level and stateAT- 5 3
9. Line pressure testAT- 5 5
10. Control valve with TCMAT- 2 3 6
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-17, "Cross-Sectional View (VQ35DE Models for 2WD)" , AT-18,
"Cross-Sectional View (VK45DE Models for 2WD)" o r AT-19,
"Cross-Sectional View (AWD Models)" .)AT- 3 0 1

TROUBLE DIAGNOSIS
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2
Shift
ShockShock is too large
when changing D1 →
D
2 or M1 → M2 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 5 and direct clutch solenoid valveAT-176,
AT-155
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. Direct clutchAT-341
3Shock is too large
when changing D2 →
D
3 or M2 → M3 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-178,
AT-159
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. High and low reverse clutchAT-339
4Shock is too large
when changing D3 →
D
4 or M3 → M4 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 3 and input clutch solenoid valveAT-174,
AT-147
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. Input clutchAT-327
No. Item Symptom Condition Diagnostic ItemReference
page