IDX INFINITI QX4 2001 Factory User Guide

ªD2º, ª22º and ª12º Positions=NBAT0012S0403
Forward clutch
Forward one-way clutch
Brake bandRear sun gear drives rear planetary carrier and combined front internal gear. Front inter-
nal gear now rotates around front sun gear accompanying front planetary carrier.
As front planetary carrier transfers the power to rear internal gear through forward clutch
and forward one-way clutch, this rotation of rear internal gear increases the speed of
rear planetary carrier compared with that of the 1st speed.
Overrun clutch
engagement conditionsD
2: Overdrive control switch in ªOFFº
Throttle opening less than 3/16
2
2: Throttle opening less than 3/16
1
2: Always engaged
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OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-21

ªD4º (OD) Position=NBAT0012S0405
High clutch
Brake band
Forward clutch
(Does not affect power transmission)Input power is transmitted to front carrier through high clutch.
This front planetary carrier turns around the sun gear which is fixed by brake band and
makes front internal gear (output) turn faster.
Engine brake At D
4position, there is no one-way clutch in the power transmission line and engine
brake can be obtained when decelerating.
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OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-23

Control System=NBAT0013OUTLINENBAT0013S01The automatic transmission senses vehicle operating conditions through various sensors. It always controls
the optimum shift position and reduces shifting and lock-up shocks.
SENSORS
ETCM
EACTUATORS
PNP switch
Throttle position sensor
Closed throttle position switch
Wide open throttle position switch
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed sensor
Overdrive control switch
ASCD control unit
Stop lamp switch
Turbine revolution sensorShift control
Line pressure control
Lock-up control
Overrun clutch control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication
line
Duet-EU controlShift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch sole-
noid valve
Line pressure solenoid valve
O/D OFF indicator lamp
T/F control unit
CONTROL SYSTEMNBAT0013S02
SAT125K
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OVERALL SYSTEM
Control System
AT-25

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Normal ControlNBAT0180S0101The line pressure to throttle opening characteristics is set for suit-
able clutch operation.
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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)
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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

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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.
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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

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

Priority Items
1 Freeze frame data Misfire Ð DTC: P0300 - P0306
Fuel Injection System Function Ð DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM
memory is erased.
HOW TO ERASE DTCNBAT0016S02The diagnostic trouble code can be erased by CONSULT-II, GST or ECM DIAGNOSTIC TEST MODE as
described following.
IIf the battery terminal is disconnected, the diagnostic trouble code will be lost within 24 hours.
IWhen you erase the DTC, using CONSULT-II or GST is easier and quicker than switching the mode
selector on the ECM.
The following emission-related diagnostic information is cleared from the ECM memory when erasing DTC
related to OBD-II. For details, refer to EC-60, ªEmission-related Diagnostic Informationº.
IDiagnostic trouble codes (DTC)
I1st trip diagnostic trouble codes (1st trip DTC)
IFreeze frame data
I1st trip freeze frame data
ISystem readiness test (SRT) codes
ITest values
HOW TO ERASE DTC (WITH CONSULT-II)NBAT0016S03IIf a DTC is displayed for both ECM and TCM, it needs to be erased for both ECM and TCM.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
5 seconds and then turn it ªONº (engine stopped) again.
2. Turn CONSULT-II ªONº and touch ªA/Tº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. (The DTC in the TCM will be erased.) Then touch ªBACKº twice.
5. Touch ªENGINEº.
6. Touch ªSELF-DIAG RESULTSº.
7. Touch ªERASEº. (The DTC in the ECM will be erased.)
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
OBD-II Diagnostic Trouble Code (DTC) (Cont'd)
AT-35

SAT964I
Malfunction Indicator Lamp (MIL)=NBAT0183The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON
without the engine running. This is a bulb check.
IIf the MIL does not light up, refer to EL-114, ªSchematicº.
(Or refer to EC-648, ªWiring Diagramº.)
2. When the engine is started, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction. For detail, refer to
EC-59, ªIntroductionº.
CONSULT-IINBAT0184After performing ªSELF-DIAGNOSTIC PROCEDURE (WITH CON-
SULT-II)º (AT-37), place check marks for results on the ªDIAGNOS-
TIC WORKSHEETº, AT-55. Reference pages are provided follow-
ing the items.
NOTICE:
1) The CONSULT-II electrically displays shift timing and lock-up
timing (that is, operation timing of each solenoid).
Check for time difference between actual shift timing and the
CONSULT-II display. If the difference is noticeable, mechani-
cal parts (except solenoids, sensors, etc.) may be malfunction-
ing. Check mechanical parts using applicable diagnostic pro-
cedures.
2) Shift schedule (which implies gear position) displayed on
CONSULT-II and that indicated in Service Manual may differ
slightly. This occurs because of the following reasons:
IActual shift schedule has more or less tolerance or allowance,
IShift schedule indicated in Service Manual refers to the point
where shifts start, and
IGear position displayed on CONSULT-II indicates the point
where shifts are completed.
3) Shift solenoid valve ªAº or ªBº is displayed on CONSULT-II at
the start of shifting. Gear position is displayed upon completion
of shifting (which is computed by TCM).
4) Additional CONSULT-II information can be found in the Opera-
tion Manual supplied with the CONSULT-II unit.
SAT014K
SELF-DIAGNOSTIC PROCEDURE (WITH CONSULT-II)NBAT0184S011. Turn on CONSULT-II and touch ªENGINEº for OBD-II detected
items or touch ªA/Tº for TCM self-diagnosis.
If A/T is not displayed, check TCM power supply and ground
circuit. Refer to AT-92. If result is NG, refer to EL-9, ªSche-
maticº.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Malfunction Indicator Lamp (MIL)
AT-37

Detected items
(Screen terms for CONSULT-II, ªSELF-DIAG
RESULTSº test mode)
Malfunction is detected when ...TCM self-diagnosis OBD-II (DTC)
Available by
O/D OFF
indicator lamp or
ªA/Tº on CONSULT-IIAvailable by
malfunction
indicator lamp*2,
ªENGINEº on CON-
SULT-II or GST ªA/Tº ªENGINEº
Overrun clutch solenoid valveITCM detects an improper volt-
age drop when it tries to operate
the solenoid valve.X P1760
OVERRUN CLUTCH
S/VO/R CLUCH SOL/
CIRC
T/C clutch solenoid valveITCM detects an improper volt-
age drop when it tries to operate
the solenoid valve.X P0740
T/C CLUTCH SOL/V TCC SOLENOID/
CIRC
Line pressure solenoid valveITCM detects an improper volt-
age drop when it tries to operate
the solenoid valve.X P0745
LINE PRESSURE
S/VL/PRESS SOL/CIRC
Throttle position sensor
Throttle position switchITCM receives an excessively
low or high voltage from the
sensor.X P1705
THROTTLE POSI
SENTP SEN/CIRC A/T
Engine speed signalITCM does not receive the
proper voltage signal from the
ECM.X P0725
ENGINE SPEED SIG
A/T fluid temperature sensorITCM receives an excessively
low or high voltage from the
sensor.X P0710
BATT/FLUID TEMP
SENATF TEMP SEN/
CIRC
Engine controlIThe ECM-AT communication
line is open or shorted.X EC-440, EC-603
A/T COMM LINE Ð
Turbine revolution sensorITCM does not receive the
proper voltage signal from the
sensor.XÐ
TURBINE REV
Ð
TCM (RAM)ITCM memory (RAM) is malfunc-
tioning.
ÐÐ
CONTROL UNIT
(RAM)Ð
TCM (ROM)ITCM memory (ROM) is malfunc-
tioning.
ÐÐ
CONTROL UNIT
(ROM)Ð
TCM (EEP ROM)ITCM memory (EEP ROM) is
malfunctioning.
ÐÐ
CONTROL UNIT
(EEP ROM)Ð
Initial startIThis is not a malfunction mes-
sage (Whenever shutting off a
power supply to the TCM, this
message appears on the
screen.)XÐ
INITIAL START
Ð
No failure
(NO DTC IS DETECTED FURTHER TEST-
ING MAY BE REQUIRED)INo failure has been detected.
XX
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
AT-39