2005 INFINITI FX35 torque

A/T CONTROL SYSTEM AT-35
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Revision: 2005 July 2005 FX
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.
Lock-up ControlACS002LK
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
PCIA0013E
selector lever D position M5 position M4 position
Gear position 5 4 5 4
Lock-up ×– ××
Slip lock-up ××––
PCIA0014E

AT-36
A/T CONTROL SYSTEM
Revision: 2005 July 2005 FX
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 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 4th and 5th gears at both low speed and when the accelerator has a low
degree of opening.
Engine Brake ControlACS002LL

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.
SCIA1520E

A/T CONTROL SYSTEM AT-37
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Revision: 2005 July 2005 FX
Control ValveACS002LM
FUNCTION OF CONTROL VALVE
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.)
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.

AT-44
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
A/T Interlock

If there is an A/T interlock judgment malfunction, the transmission is fixed in 2nd gear to make driving pos-
sible.
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 transmission 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 transmission 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 transmission 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 transmission 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 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

TROUBLE DIAGNOSIS AT-47
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Revision: 2005 July 2005 FX
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 Blinks for about 8 seconds. ❏ 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 3
2 ❏
A/T fluid inspection AT- 5 2❏ Leak (Repair leak location.)
❏ Sta t e
❏ Amount
3 ❏
Stall test and line pressure test AT- 5 2
, 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:

AT-48
TROUBLE DIAGNOSIS
Revision: 2005 July 2005 FX
4 ❏
Perform all road tests and enter checks in required inspection items. AT- 5 6
4-1. Check before engine is started
AT- 5 6
❏ The A/T CHECK Indicator Lamp does come on. AT- 1 9 3 .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 9 3
,AT- 1 0 3
❏ AT-106, "DTC U1000 CAN COMMUNICATION LINE" .
❏ AT-109, "
DTC P0615 START SIGNAL CIRCUIT" .
❏ AT- 11 3 , "
DTC P0700 TCM"
❏ AT- 11 4 , "DTC P0705 PARK/NEUTRAL POSITION SWITCH" .
❏ AT- 11 8 , "
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 P1702 TRANSMISSION CONTROL MODULE (RAM)" .
❏ AT-132, "
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)" .
❏ AT-133, "
DTC P1705 THROTTLE POSITION SENSOR" .
❏ AT-136, "
DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT" .
❏ AT-141, "
DTC P1716 TURBINE REVOLUTION SENSOR" .
❏ AT-143, "
DTC P1721 VEHICLE SPEED SENSOR MTR" .
❏ AT-145, "
DTC P1730 A/T INTERLOCK" .
❏ AT-148, "
DTC P1731 A/T 1ST ENGINE BRAKING" .
❏ AT-150, "
DTC P1752 INPUT CLUTCH SOLENOID VALVE" .
❏ AT-152, "
DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-154, "
DTC P1757 FRONT BRAKE SOLENOID VALVE" .
❏ AT-156, "
DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-158, "
DTC P1762 DIRECT CLUTCH SOLENOID VALVE" .
❏ AT-160, "
DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-162, "
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE" .
❏ AT-164, "
DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION" .
❏ AT-166, "
DTC P1772 LOW COAST BRAKE SOLENOID VALVE" .
❏ AT-168, "
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-170, "
DTC P1815 MANUAL MODE SWITCH" .
❏ AT-175, "
DTC P1841 ATF PRESSURE SWITCH 1" .
❏ AT-177, "
DTC P1843 ATF PRESSURE SWITCH 3" .
❏ AT-179, "
DTC P1845 ATF PRESSURE SWITCH 5" .
❏ AT-181, "
DTC P1846 ATF PRESSURE SWITCH 6" .
4-2. Check at Idle
AT- 5 7
❏ AT-194, "Engine Cannot Be Started in “P” or “N” Position" .
❏ AT-195, "
In “P” Position, Vehicle Moves When Pushed"
❏ AT-196, "In “N” Position, Vehicle Moves" .
❏ AT-197, "
Large Shock (“N” to “D” Position)" .
❏ AT-200, "
Vehicle Does Not Creep Backward in “R” Position" .
❏ AT-203, "
Vehicle Does Not Creep Forward in “D” Position" .
4-3. Cruise Test
AT- 5 8
Part 1
❏ AT-205, "
Vehicle Cannot Be Started from D1" .
❏ AT-208, "
A/T Does Not Shift: D1 → D2" .
❏ AT-210, "
A/T Does Not Shift: D2 → D3" .
❏ AT-212, "
A/T Does Not Shift: D3 → D4" .
❏ AT-215, "
A/T Does Not Shift: D4 → D5" .
❏ AT-217, "
A/T Does Not Perform Lock-up"
❏ AT-219, "A/T Does Not Hold Lock-up Condition" .
❏ AT-221, "
Lock-up Is Not Released" .
❏ AT-221, "
Engine Speed Does Not Return to Idle" .

TROUBLE DIAGNOSIS AT-49
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44-3 Part 2
AT- 6 0
❏ AT- 2 0 5 , "Vehicle Cannot Be Started from D1" .
❏ AT- 2 0 8 , "
A/T Does Not Shift: D1 → D2" .
❏ AT- 2 1 0 , "
A/T Does Not Shift: D2 → D3" .
❏ AT- 2 1 2 , "
A/T Does Not Shift: D3 → D4" .
Part 3 AT- 6 1
❏ AT- 2 2 3 , "Cannot Be Changed to Manual Mode" .
❏ AT- 2 2 3 , "
A/T Does Not Shift: 5th Gear → 4th Gear" .
❏ AT- 2 2 5 , "
A/T Does Not Shift: 4th Gear → 3rd Gear" .
❏ AT- 2 2 7 , "
A/T Does Not Shift: 3rd Gear → 2nd Gear" .
❏ AT- 2 2 9 , "
A/T Does Not Shift: 2nd Gear → 1st Gear" .
❏ AT- 2 3 1 , "
Vehicle Does Not Decelerate by Engine Brake" .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 9 3
,AT- 1 0 3
❏ AT-106, "DTC U1000 CAN COMMUNICATION LINE" .
❏ AT-109, "
DTC P0615 START SIGNAL CIRCUIT" .
❏ AT-113, "
DTC P0700 TCM"
❏ AT-114, "DTC P0705 PARK/NEUTRAL POSITION SWITCH" .
❏ 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 P1702 TRANSMISSION CONTROL MODULE (RAM)" .
❏ AT-132, "
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)" .
❏ AT-133, "
DTC P1705 THROTTLE POSITION SENSOR" .
❏ AT-136, "
DTC P1710 A/T FLUID TEMPERATURE SENSOR CIRCUIT" .
❏ AT-141, "
DTC P1716 TURBINE REVOLUTION SENSOR" .
❏ AT-143, "
DTC P1721 VEHICLE SPEED SENSOR MTR" .
❏ AT-145, "
DTC P1730 A/T INTERLOCK" .
❏ AT-148, "
DTC P1731 A/T 1ST ENGINE BRAKING" .
❏ AT-150, "
DTC P1752 INPUT CLUTCH SOLENOID VALVE" .
❏ AT-152, "
DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-154, "
DTC P1757 FRONT BRAKE SOLENOID VALVE" .
❏ AT-156, "
DTC P1759 FRONT BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-158, "
DTC P1762 DIRECT CLUTCH SOLENOID VALVE" .
❏ AT-160, "
DTC P1764 DIRECT CLUTCH SOLENOID VALVE FUNCTION" .
❏ AT-162, "
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE" .
❏ AT-164, "
DTC P1769 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
FUNCTION" .
❏ AT-166, "
DTC P1772 LOW COAST BRAKE SOLENOID VALVE" .
❏ AT-168, "
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTION" .
❏ AT-170, "
DTC P1815 MANUAL MODE SWITCH" .
❏ AT-175, "
DTC P1841 ATF PRESSURE SWITCH 1" .
❏ AT-177, "
DTC P1843 ATF PRESSURE SWITCH 3" .
❏ AT-179, "
DTC P1845 ATF PRESSURE SWITCH 5" .
❏ AT-181, "
DTC P1846 ATF PRESSURE SWITCH 6" .
5 ❏ Inspect each system for items found to be NG in the self-diagnostics and repair or replace the malfunctioning parts.
6 ❏ Perform all road tests and enter the checks again for the required items. AT- 5 6
7 ❏
For any remaining NG items, perform the “diagnostics procedure” and repair or replace the malfunctioning
parts. See the chart for diagnostics by symptoms. (This chart also contains other symptoms and inspection pro-
cedures.) AT- 6 4
8
❏ Erase the results of the self-diagnostics from the TCM. AT- 4 1,
AT-
103

TROUBLE DIAGNOSIS AT-53
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Revision: 2005 July 2005 FX
5. While holding down the foot brake, gradually press down the
accelerator pedal.
6. Quickly read off the stall speed, then quickly remove your foot from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
7. Move the selector lever to the “N” position.
8. Cool down the ATF. CAUTION:
Run the engine at idle for at least 1 minute.
Judgement of Stall Test
O: Stall speed within standard value position
H: Stall speed higher than standard value
L: Stall speed lower than standard value
SAT514G
Stall speed:
VQ35DE engine: 2,200 - 2,400 rpm
VK45DE engine: 1,950 - 2,250 rpm
SCIA6424E
Selector lever position Expected problem location
“D”, “M” “R”
Stall speed HO

Forward brake

Forward one-way clutch

1st one-way clutch

3rd one-way clutch
OH

Reverse brake
LL

Engine and torque converter one-way clutch
HH

Line pressure low