shift INFINITI FX35 2005 User Guide

A/T CONTROL SYSTEM AT-33
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Line Pressure ControlACS002LI

When an input torque signal equivalent to the engine drive force is sent from the ECM to the TCM, the
TCM controls the line pressure solenoid.

This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the
pressure of the operating oil discharged from the oil pump to the line pressure most appropriate to the
driving state.
LINE PRESSURE CONTROL IS BASED ON THE TCM LINE PRESSURE CHARACTERISTIC
PATTERN

The TCM has stored in memory a number of patterns for the optimum line pressure characteristic for the
driving state.

In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the
TCM controls the line pressure solenoid current valve and thus controls the line pressure.
Normal Control
Each clutch is adjusted to the necessary pressure to match the
engine drive force.
Back-Up Control (Engine Brake)
When the select operation is performed during driving and the trans-
mission is shifted down, the line pressure is set according to the
vehicle speed.
PCIA0007E
PCIA0008E
PCIA0009E

AT-34
A/T CONTROL SYSTEM
Revision: 2005 July 2005 FX
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 ControlACS002LJ
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.
PCIA0010E
PCIA0011E
PCIA0012E

A/T CONTROL SYSTEM AT-35
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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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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.

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TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartACS002LS
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 DTCs, first perform the trouble diagnosis for DTC U1000. Refer to
AT- 1 0 6
.
Fail-safeACS002LT
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is a 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 transmission is fixed in 2nd, 4th or 5th
(depending on the breakdown position), so the customer should feel “slipping” or “poor acceleration”. When
fail-safe mode is triggered, when the ignition switch is switched “ON”, the A/T CHECK indicator lamp flashes
for about 8 seconds. (Refer to AT- 1 0 3 , "
TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)" ).
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 transmission 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. Also, the A/T CHECK indicator lamp flashes for about 8 seconds once, then is cleared.
Therefore, the customer's vehicle has returned to normal, so handle according to the “WORK FLOW” (Refer to
AT- 4 6
).
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
transmission 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 AT-45
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How to Perform Trouble Diagnosis for Quick and Accurate RepairACS002LU
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelerator 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 6 , "
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 7
) 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

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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