2006 INFINITI FX35 torque

A/T CONTROL SYSTEM AT-35
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Revision: 2006 December 2006 FX35/FX45
During Shift Change
The necessary and adequate line pressure for shift change is set.
For this reason, line pressure pattern setting corresponds to input
torque and gearshift selection. Also, line pressure characteristic is
set according to engine speed, during engine brake operation.
At Low Fluid Temperature
When the A/T fluid temperature drops below the prescribed tempera-
ture, in order to speed up the action of each friction element, the line
pressure is set higher than the normal line pressure characteristic.
Shift ControlNCS001B3
The clutch pressure control solenoid is controlled by the signals from the switches and sensors. Thus, the
clutch pressure is adjusted to be appropriate to the engine load state and vehicle driving state. It becomes
possible to finely control the clutch hydraulic pressure with high precision and a smoother shift change charac-
teristic is attained.
SHIFT CHANGE
The clutch is controlled with the optimum timing and oil pressure by the engine speed, engine torque informa-
tion, etc.
PCIA0010E
PCIA0011E
PCIA0012E

AT-36
A/T CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
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 accelerator 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.
Shift Change System Diagram
PCIA0013E
SCIA6483E

A/T CONTROL SYSTEM AT-37
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Revision: 2006 December 2006 FX35/FX45
Lock-up ControlNCS001B4
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 gradually 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 coupling 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.
selector lever D position M5 position M4 position M3 position
Gear position 54543
Lock-up ×–×××
Slip lock-up ××–––
PCIA0014E

AT-38
A/T CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
Engine Brake ControlNCS001B5

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 ValveNCS001B6
FUNCTION OF CONTROL VALVE
SCIA1520E
Name Function
Torque converter regulator valve In 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 sleeve Adjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for
the driving state.
Front brake control valve When 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 valve Adjusts 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 A Adjusts the line pressure and produces the constant pressure (pilot pressure) required
for line pressure control, shift change control, and lock-up control.
Pilot valve B Adjusts 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 valve When 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 valve When 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 AT-39
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Revision: 2006 December 2006 FX35/FX45
FUNCTION OF ATF PRESSURE SWITCH
Input clutch control valve When 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 valve When 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 sleeve Switches the lock-up to operating or released. Also, by performing the lock-up operation
transiently, lock-up smoothly.
Torque converter lubrication valve Operates 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 valve Sends 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.

TROUBLE DIAGNOSIS AT-45
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Revision: 2006 December 2006 FX35/FX45
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 (electrical or functional) malfunction occurs, in order to make driving possible, if the solenoid is ON,
the transmission 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 (electrical or functional) malfunction 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 (electrical or functional) malfunction 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 (electrical or functional) malfunction occurs with the solenoid ON, in order to make driving possible, the A/
T is held in 5th gear; if the solenoid is OFF, 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 prohib-
ited.
Gear position ATF pressure switch output
Fail-safe function Clutch 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 pattern 3rd – X X –

Held in
2nd gear OFF OFF ON OFF OFF OFF
4th – X X –
Held in
2nd gear OFF OFF ON OFF OFF OFF
5th X X – X
Held in
2nd gear OFF OFF ON OFF OFF OFF

AT-48
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS

WHAT ..... Vehicle and A/T model

WHEN ..... Date, Frequencies

WHERE ..... Road conditions

HOW..... Operating conditions, Symptoms
Diagnostic Worksheet Chart
Customer name MR/MS Model and Year VIN
Trans. Model Engine Mileage
Malfunction Date Manuf. Date In Service Date
Frequency ❏ Continuous ❏ Intermittent ( times a day)
Symptoms ❏ Vehicle does not move. ( ❏ Any position ❏ Particular position)
❏ No up-shift ( ❏ 1st → 2nd ❏ 2nd → 3rd ❏ 3rd → 4th ❏ 4th → 5th)
❏ No down-shift ( ❏ 5th → 4th ❏ 4th → 3rd ❏ 3rd → 2nd ❏ 2nd → 1st)
❏ Lock-up malfunction
❏ Shift point too high or too low.
❏ Shift shock or slip ( ❏ N → D ❏ Lock-up ❏ Any drive position)
❏ Noise or vibration
❏ No kick down
❏ No pattern select
❏ Others
()
A/T CHECK indicator lamp ❏ Continuously lit ❏ Not lit
Malfunction indicator lamp (MIL) ❏ Continuously lit ❏ Not lit
1 ❏ Read the item on cautions concerning fail-safe and understand the customer's complaint. AT- 4 4
2 ❏
A/T fluid inspection AT- 5 3❏ Leak (Repair leak location.)
❏ State
❏ Amount
3 ❏
Stall test and line pressure test AT- 5 3
, AT-
54❏ Stall test
❏ Torque converter one-way clutch
❏ Front brake
❏ High and low reverse clutch
❏ Low coast brake
❏ Forward brake
❏ Reverse brake
❏ Forward one-way clutch ❏
1st one-way clutch
❏ 3rd one-way clutch
❏ Engine
❏ Line pressure low
❏ Except for input clutch and direct
clutch, clutches and brakes OK
❏ Line pressure inspection - Suspected part:

TROUBLE DIAGNOSIS AT-49
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Revision: 2006 December 2006 FX35/FX45
4 ❏
Perform all road tests and enter checks in required inspection items. AT- 5 6
4-1. Check before engine is started
AT- 5 7
❏ The A/T CHECK Indicator Lamp does come on. AT- 1 8 9 .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 9 2
, AT- 1 0 2 .
❏ AT-104, "
DTC U1000 CAN COMMUNICATION LINE" .
❏ AT-107, "
DTC P0615 START SIGNAL CIRCUIT" .
❏ AT- 111 , "
DTC P0700 TCM"
❏ AT-112, "DTC P0705 PARK/NEUTRAL POSITION SWITCH" .
❏ AT-116, "
DTC P0717 TURBINE REVOLUTION SENSOR" .
❏ AT-118, "
DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)" .
❏ AT-123, "
DTC P0725 ENGINE SPEED SIGNAL" .
❏ AT-125, "
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE" .
❏ AT-127, "
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)" .
❏ AT-129, "
DTC P0745 LINE PRESSURE SOLENOID VALVE" .
❏ AT-131, "
DTC P1705 THROTTLE POSITION SENSOR" .
❏ AT-134, "
DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT" .
❏ AT-139, "
DTC P1721 VEHICLE SPEED SENSOR MTR" .
❏ AT-141, "
DTC P1730 A/T INTERLOCK" .
❏ AT-144, "
DTC P1731 A/T 1ST ENGINE BRAKING" .
❏ AT-146, "
DTC P1752 INPUT CLUTCH SOLENOID VALVE" .
❏ AT-148, "
DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-150, "
DTC P1757 FRONT BRAKE SOLENOID VALVE" .
❏ AT-152, "
DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-154, "
DTC P1762 DIRECT CLUTCH SOLENOID VALVE" .
❏ AT-156, "
DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-158, "
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE" .
❏ AT-160, "
DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION" .
❏ AT-162, "
DTC P1772 LOW COAST BRAKE SOLENOID VALVE" .
❏ AT-164, "
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-166, "
DTC P1815 MANUAL MODE SWITCH" .
❏ AT-171, "
DTC P1841 ATF PRESSURE SWITCH 1" .
❏ AT-173, "
DTC P1843 ATF PRESSURE SWITCH 3" .
❏ AT-175, "
DTC P1845 ATF PRESSURE SWITCH 5" .
❏ AT-177, "
DTC P1846 ATF PRESSURE SWITCH 6" .
4-2. Check at Idle
AT- 5 7
❏ AT- 1 9 0 , "Engine Cannot Be Started in “P” or “N” Position" .
❏ AT- 1 9 1 , "
In “P” Position, Vehicle Moves When Pushed"
❏ AT- 1 9 2 , "In “N” Position, Vehicle Moves" .
❏ AT- 1 9 3 , "
Large Shock (“N” to “D” Position)" .
❏ AT- 1 9 6 , "
Vehicle Does Not Creep Backward in “R” Position" .
❏ AT- 1 9 9 , "
Vehicle Does Not Creep Forward in “D” Position" .
4-3. Cruise Test
AT- 5 8
Part 1
❏ AT- 2 0 1 , "
Vehicle Cannot Be Started From D1" .
❏ AT- 2 0 4 , "
A/T Does Not Shift: D1 → D2" .
❏ AT- 2 0 6 , "
A/T Does Not Shift: D2 → D3" .
❏ AT- 2 0 8 , "
A/T Does Not Shift: D3 → D4" .
❏ AT- 2 11 , "
A/T Does Not Shift: D4 → D5" .
❏ AT- 2 1 3 , "
A/T Does Not Lock-up"
❏ AT- 2 1 5 , "A/T Does Not Hold Lock-up Condition" .
❏ AT- 2 1 7 , "
Lock-up Is Not Released" .
❏ AT- 2 1 7 , "
Engine Speed Does Not Return to Idle" .