vin INFINITI QX4 2001 Factory Service Manual

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Nissan North America, Inc.
Technical Service Information
39001 Sunrise Drive, P.O. Box 9200
Farmington Hills, MI USA 48331
FAX: (248) 488-3910
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IBefore assembly, apply a coat of recommended ATF to all
parts. Apply petroleum jelly to protect O-rings and seals, or
hold bearings and washers in place during assembly. Do not
use grease.
IExtreme care should be taken to avoid damage to O-rings,
seals and gaskets when assembling.
IReplace ATF cooler if excessive foreign material is found in oil
pan or clogging strainer. Refer to ªATF COOLER SERVICEº,
AT-9.
IAfter overhaul, refill the transmission with new ATF.
IWhen the A/T drain plug is removed, only some of the fluid is
drained. Old A/T fluid will remain in torque converter and ATF
cooling system.
Always follow the procedures when changing A/T fluid. Refer
to MA-21, ªChanging A/T Fluidº.
Service Notice or PrecautionsNBAT0004FAIL-SAFENBAT0004S01The TCM has an electronic Fail-Safe (limp home mode). This allows the vehicle to be driven even if a major
electrical input/output device circuit is damaged.
Under Fail-Safe, the vehicle always runs in third gear, even with a shift lever position of ª1º, ª2º or ªDº. The
customer may complain of sluggish or poor acceleration.
When the ignition key is turned ªONº following Fail-Safe operation, O/D OFF indicator lamp blinks for about
8 seconds. (For ªTCM SELF-DIAGNOSTIC PROCEDURE (No Tools)º, refer to AT-46.)
Fail-Safe may occur without electrical circuit damage if the vehicle is driven under extreme conditions (such
as excessive wheel spin followed by sudden braking). To recover normal shift pattern, turn the ignition key
ªOFFº for 5 seconds, then ªONº.
The blinking of the O/D OFF indicator lamp for about 8 seconds will appear only once and be cleared. The
customer may resume normal driving conditions.
Always follow the ªWORK FLOWº (Refer to AT-57).
The SELF-DIAGNOSIS results will be as follows:
The first SELF-DIAGNOSIS will indicate damage to the vehicle speed sensor or the revolution sensor.
During the next SELF-DIAGNOSIS, performed after checking the sensor, no damages will be indicated.
TORQUE CONVERTER SERVICENBAT0004S04The torque converter should be replaced under any of the following conditions:
IExternal leaks in the hub weld area.
IConverter hub is scored or damaged.
IConverter pilot is broken, damaged or fits poorly into crankshaft.
ISteel particles are found after flushing the cooler and cooler lines.
IPump is damaged or steel particles are found in the converter.
IVehicle has TCC shudder and/or no TCC apply. Replace only after all hydraulic and electrical diagnoses
have been made. (Converter clutch material may be glazed.)
IConverter is contaminated with engine coolant containing antifreeze.
IInternal failure of stator roller clutch.
IHeavy clutch debris due to overheating (blue converter).
ISteel particles or clutch lining material found in fluid filter or on magnet when no internal parts in unit are
worn or damaged Ð indicates that lining material came from converter.
The torque converter should not be replaced if:
IThe fluid has an odor, is discolored, and there is no evidence of metal or clutch facing particles.
PRECAUTIONS
Precautions (Cont'd)
AT-8

Special Service ToolsNBAT0006The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
ST2505S001
(J34301-C)
Oil pressure gauge set
1 ST25051001
(Ð)
Oil pressure gauge
2 ST25052000
(Ð)
Hose
3 ST25053000
(Ð)
Joint pipe
4 ST25054000
(Ð)
Adapter
5 ST25055000
(Ð)
Adapter
NT097
Measuring line pressure
ST07870000
(J37068)
Transmission case stand
NT421
Disassembling and assembling A/T
a: 182 mm (7.17 in)
b: 282 mm (11.10 in)
c: 230 mm (9.06 in)
d: 100 mm (3.94 in)
KV31102100
(J37065)
Torque converter one-
way clutch check tool
NT098
Checking one-way clutch in torque converter
ST25850000
(J25721-A)
Sliding hammer
NT422
Removing oil pump assembly
a: 179 mm (7.05 in)
b: 70 mm (2.76 in)
c: 40 mm (1.57 in) dia.
d: M12 x 1.75P
KV31102400
(J34285 and J34285-87)
Clutch spring compres-
sor
NT423
Removing and installing clutch return springs
a: 320 mm (12.60 in)
b: 174 mm (6.85 in)
PREPARATION
Special Service Tools
AT-10

TCM FUNCTION=NBAT0013S03The function of the TCM is to:
IReceive input signals sent from various switches and sensors.
IDetermine required line pressure, shifting point, lock-up operation, and engine brake operation.
ISend required output signals to the respective solenoids.
INPUT/OUTPUT SIGNAL OF TCMNBAT0013S04
Sensors and solenoid valves Function
InputPNP switch Detects select lever position and sends a signal to TCM.
Throttle position sensor Detects throttle valve position and sends a signal to TCM.
Closed throttle position switch Detects throttle valve's fully-closed position and sends a signal to TCM.
Wide open throttle position switchDetects a throttle valve position of greater than 1/2 of full throttle and sends
a signal to TCM.
Engine speed signal From ECM.
A/T fluid temperature sensor Detects transmission fluid temperature and sends a signal to TCM.
Revolution sensor Detects output shaft rpm and sends a signal to TCM.
Vehicle speed sensorUsed as an auxiliary vehicle speed sensor. Sends a signal when revolution
sensor (installed on transmission) malfunctions.
Overdrive control switchSends a signal, which prohibits a shift to ªD
4º (overdrive) position, to the
TCM.
ASCD control unitSends the cruise signal and ªD
4º (overdrive) cancellation signal from ASCD
control unit to TCM.
Turbine revolution sensor Sends an input shaft revolution signal.
Stop lamp switch Sends the lock-up release signal to the TCM at time of D
4(lock-up).
OutputShift solenoid valve A/BSelects shifting point suited to driving conditions in relation to a signal sent
from TCM.
Line pressure solenoid valveRegulates (or decreases) line pressure suited to driving conditions in rela-
tion to a signal sent from TCM.
Torque converter clutch solenoid
valveRegulates (or decreases) lock-up pressure suited to driving conditions in
relation to a signal sent from TCM.
Overrun clutch solenoid valveControls an ªengine brakeº effect suited to driving conditions in relation to a
signal sent from TCM.
O/D OFF indicator lamp Shows TCM faults, when A/T control components malfunction.
Control MechanismNBAT0180LINE PRESSURE CONTROLNBAT0180S01TCM has the various line pressure control characteristics to meet
the driving conditions.
An ON-OFF duty signal is sent to the line pressure solenoid valve
based on TCM characteristics.
Hydraulic pressure on the clutch and brake is electronically con-
trolled through the line pressure solenoid valve to accommodate
engine torque. This results in smooth shift operation.
OVERALL SYSTEM
Control System (Cont'd)
AT-26

SAT003J
Normal ControlNBAT0180S0101The line pressure to throttle opening characteristics is set for suit-
able clutch operation.
SAT004J
Back-up Control (Engine brake)NBAT0180S0102If the selector lever is shifted to ª2º position while driving in D4(OD)
or D
3, great driving force is applied to the clutch inside the trans-
mission. Clutch operating pressure (line pressure) must be
increased to deal with this driving force.
SAT005J
During Shift ChangeNBAT0180S0103The line pressure is temporarily reduced corresponding to a
change in engine torque when shifting gears (that is, when the shift
solenoid valve is switched for clutch operation) to reduce shifting
shock.
At Low Fluid TemperatureNBAT0180S0104IFluid viscosity and frictional characteristics of the clutch facing
change with fluid temperature. Clutch engaging or band-con-
tacting pressure is compensated for, according to fluid
temperature, to stabilize shifting quality.
SAT006J
IThe line pressure is reduced below 60ÉC (140ÉF) to prevent
shifting shock due to low viscosity of automatic transmission
fluid when temperature is low.
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OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-27

Pilot pressure generated by the operation of shift solenoid valves
A and B is applied to the end face of shift valves A and B.
The drawing above shows the operation of shift valve B. When the
shift solenoid valve is ªONº, pilot pressure applied to the end face
of the shift valve overcomes spring force, moving the valve upward.
LOCK-UP CONTROLNBAT0180S03The torque converter clutch piston in the torque converter is locked
to eliminate torque converter slip to increase power transmission
efficiency. The solenoid valve is controlled by an ON-OFF duty
signal sent from the TCM. The signal is converted to oil pressure
signal which controls the torque converter clutch piston.
Conditions for Lock-up OperationNBAT0180S0301When vehicle is driven in 4th gear position, vehicle speed and
throttle opening are detected. If the detected values fall within the
lock-up zone memorized in the TCM, lock-up is performed.
Overdrive control switch ON OFF
Selector lever ªDº position
Gear position D
4D3
Vehicle speed sensor More than set value
Throttle position sensor Less than set opening
Closed throttle position switch OFF
A/T fluid temperature sensor More than 40ÉC (104ÉF)
SAT010J
Torque Converter Clutch Solenoid Valve ControlNBAT0180S0302The torque converter clutch solenoid valve is controlled by the
TCM. The plunger closes the drain circuit during the ªOFFº period,
and opens the circuit during the ªONº period. If the percentage of
OFF-time increases in one cycle, the pilot pressure drain time is
reduced and pilot pressure remains high.
The torque converter clutch piston is designed to slip to adjust the
ratio of ON-OFF, thereby reducing lock-up shock.
SAT011J
OFF-time INCREASING
"
Amount of drain DECREASING
"
Pilot pressure HIGH
"
Lock-up RELEASING
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OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-29

SAT015J
Overrun Clutch Solenoid Valve ControlNBAT0180S0402The overrun clutch solenoid valve is operated by an ON-OFF sig-
nal transmitted by the TCM to provide overrun clutch control
(engine brake control).
When this solenoid valve is ªONº, the pilot pressure drain port
closes. When it is ªOFFº, the drain port opens.
During the solenoid valve ªONº pilot pressure is applied to the end
face of the overrun clutch control valve.
SAT049J
Overrun Clutch Control Valve OperationNBAT0180S0403When the solenoid valve is ªONº, pilot pressure A is applied to the
overrun clutch control valve. This pushes up the overrun clutch
control valve. The line pressure is then shut off so that the clutch
does not engage.
When the solenoid valve is ªOFFº, pilot pressure A is not gener-
ated. At this point, the overrun clutch control valve moves down-
ward by spring force. As a result, overrun clutch operation pressure
is provided by the overrun clutch reducing valve. This causes the
overrun clutch to engage.
In the ª1º position, the overrun clutch control valve remains pushed
down so that the overrun clutch is engaged at all times.
Control ValveNBAT0181FUNCTION OF CONTROL VALVENBAT0181S01
Valve name Function
IPressure regulator valve
IPressure regulator plug
IPressure regulator sleeve plugRegulate oil discharged from the oil pump to provide optimum line pressure for all
driving conditions.
Pressure modifier valve Used as a signal supplementary valve to the pressure regulator valve. Regulates
pressure-modifier pressure (signal pressure) which controls optimum line pressure for
all driving conditions.
Modifier accumulator piston Smooths hydraulic pressure regulated by the pressure modifier valve to prevent pul-
sations.
Pilot valve Regulates line pressure to maintain a constant pilot pressure level which controls
lock-up mechanism, overrun clutch, 3-2 timing required for shifting.
Accumulator control valve
Accumulator control sleeveRegulate 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.
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OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-31

Valve name Function
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 up-shifting (1st,2nd,3rd,4th gears/4th
,3rd,2nd,1st gears) in combination with shift valve B.
Shift valve B Simultaneously switches three oil circuits using output pressure of shift solenoid valve
B in relation to driving conditions (vehicle speed, throttle opening, etc.).
Provides automatic downshifting and up-shifting (1st,2nd,3rd,4th gears/4th
,3rd,2nd,1st gears) in combination with shift valve A.
Shuttle shift valve S Switches hydraulic circuits to provide 3-2 timing control and overrun clutch control in
relation to the throttle opening.
Inactivates the overrun clutch to prevent interlocking in 4th gear when the throttle is
wide open.
Overrun clutch control valve Switches hydraulic circuits to prevent engagement of the overrun clutch simulta-
neously with application of the brake band in 4th gear. (Interlocking occurs if the
overrun clutch engages during D
4gear operation.)
4-2 relay valve Memorizes that the transmission is in 4th gear. Prevents the transmission from down-
shifting from 4th gear to 3rd and then to 2nd in combination with 4-2 sequence valve
and shift valves A and B when downshifting from 4th to 2nd gear.
4-2 sequence valve Prevents band servo pressure from draining before high clutch operating pressure
and band servo releasing pressure drain (from the same circuit) during downshifting
from 4th to 2nd gear.
Servo charger valve An accumulator and a one-way orifice are used in the 2nd gear band servo oil circuit
to dampen shifting shock when shifting from 1st to 2nd gear.
To maintain adequate flow rate when downshifting from 4th or 3rd gear to 2nd gear,
the servo charger valve directs 2nd gear band servo hydraulic pressure to the circuit
without going through the one-way orifice when downshifting from 3rd or a higher
gear.
3-2 timing valve Prevents a late operation of the brake band when shifting selector lever from ªDº to
ª1º or ª2º position while driving in D
3.
ª1º reducing valve Reduces low & reverse brake pressure to dampen engine-brake shock when down-
shifting from the ª1º position 2nd gear to 1st gear.
Overrun clutch reducing valve Reduces oil pressure directed to the overrun clutch and prevents engine-brake shock.
In ª1º and ª2º 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,
torque converter clutch control plug and
torque converter clutch control sleeveActivate or inactivate the lock-up function.
Also provide smooth lock-up through transient application and release of the lock-up
system.
Shuttle shift valve D Switches hydraulic circuits so that output pressure of the torque converter clutch sole-
noid valve acts on the lock-up valve in the ªDº position of 2nd, 3rd and 4th gears. (In
the ªDº position 1st gear, lock-up is inhibited.)
ILock-up control is not affected in ªDº position 2nd, 3rd or 4th gears, unless output
pressure of the torque converter clutch solenoid valve is generated by a signal
from the control unit.
OVERALL SYSTEM
Control Valve (Cont'd)
AT-32

IntroductionNBAT0014The A/T system has two self-diagnostic systems.
The first is the emission-related on board diagnostic system (OBD-II) performed by the TCM in combination
with the ECM. The malfunction is indicated by the MIL (malfunction indicator lamp) and is stored as a DTC in
the ECM memory but not the TCM memory.
The second is the TCM original self-diagnosis indicated by the O/D OFF indicator lamp. The malfunction is
stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For detail,
refer to AT-38.
OBD-II Function for A/T SystemNBAT0182The ECM provides emission-related on board diagnostic (OBD-II) functions for the A/T system. One function
is to receive a signal from the TCM used with OBD-related parts of the A/T system. The signal is sent to the
ECM when a malfunction occurs in the corresponding OBD-related part. The other function is to indicate a
diagnostic result by means of the MIL (malfunction indicator lamp) on the instrument panel. Sensors, switches
and solenoid valves are used as sensing elements.
The MIL automatically illuminates in One or Two Trip Detection Logic when a malfunction is sensed in rela-
tion to A/T system parts.
One or Two Trip Detection Logic of OBD-IINBAT0015ONE TRIP DETECTION LOGICNBAT0015S01If a malfunction is sensed during the first test drive, the MIL will illuminate and the malfunction will be stored
in the ECM memory as a DTC. The TCM is not provided with such a memory function.
TWO TRIP DETECTION LOGICNBAT0015S02When a malfunction is sensed during the first test drive, it is stored in the ECM memory as a 1st trip DTC
(diagnostic trouble code) or 1st trip freeze frame data. At this point, the MIL will not illuminate. Ð First Trip
If the same malfunction as that experienced during the first test drive is sensed during the second test drive,
the MIL will illuminate. Ð Second Trip
A/T-related parts for which the MIL illuminates during the first or second test drive are listed below.
ItemsMIL
One trip detection Two trip detection
Shift solenoid valve A Ð DTC: P0750 X
Shift solenoid valve B Ð DTC: P0755 X
Throttle position sensor or switch Ð DTC: P1705 X
Except aboveX
The ªtripº in the ªOne or Two Trip Detection Logicº means a driving mode in which self-diagnosis is performed
during vehicle operation.
OBD-II Diagnostic Trouble Code (DTC)NBAT0016HOW TO READ DTC AND 1ST TRIP DTCNBAT0016S01DTC and 1st trip DTC can be read by the following methods.
(
with CONSULT-II orGST)CONSULT-II or GST (Generic Scan Tool) Examples: P0705, P0710, P0720,
P0725, etc.
These DTCs are prescribed by SAE J2012.
(CONSULT-II also displays the malfunctioning component or system.)
I1st trip DTC No. is the same as DTC No.
IOutput of the diagnostic trouble code indicates that the indicated circuit has a malfunction.
However, in case of the Mode II and GST they do not indicate whether the malfunction is still
occurring or occurred in the past and returned to normal.
CONSULT-II can identify them as shown below. Therefore, using CONSULT-II (if available) is rec-
ommended.
A sample of CONSULT-II display for DTC and 1st trip DTC is shown on the next page. DTC or 1st trip DTC
of a malfunction is displayed in SELF-DIAGNOSTIC RESULTS mode for ªENGINEº with CONSULT-II. Time
data indicates how many times the vehicle was driven after the last detection of a DTC.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Introduction
AT-33

SAT014K
If the DTC is being detected currently, the time data will be ª0º.
SAT015K
If a 1st trip DTC is stored in the ECM, the time data will be ª1tº.
SAT016K
Freeze Frame Data and 1st Trip Freeze Frame DataNBAT0016S0101The ECM has a memory function, which stores the driving condition such as fuel system status, calculated
load value, engine coolant temperature, short term fuel trim, long term fuel trim, engine speed and vehicle
speed at the moment the ECM detects a malfunction.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data,
and the data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-II
or GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
detail, refer to EC-81, ªCONSULT-IIº.
Only one set of freeze frame data (either 1st trip freeze frame data of freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no prior-
ity for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
OBD-II Diagnostic Trouble Code (DTC) (Cont'd)
AT-34