2008 INFINITI QX56 tow

DIAGNOSIS SENSOR UNITSR-17
< ON-VEHICLE REPAIR >
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DIAGNOSIS SENSOR UNIT
Removal and InstallationINFOID:0000000001602208
REMOVAL
CAUTION:
• Before servicing the SRS, turn the ignition switch off, disconnect both battery cables and wait at least 3 minutes.
• Do not use old bolts; replace with new bolts.
• Check diagnosis sensor unit bracket to make sure it is free of deformities, dents, cracks or rust. If it
shows any visible signs of damage, replace with new one.
• Replace diagnosis sensor unit if it has been dropped or sustained an impact.
1. Disconnect the harness connectors for the following SRS components. Refer to SR-13, "
Removal and
Installation" (Side curtain air bag module), SE-71, "Disassembly and Assembly" (Side air bag module),
SB-4, "
Removal and Installation of Front Seat Belt" (Front seat belt pre-tensioner).
2. Remove center console. Refer to IP-20, "
Removal and Installation".
3. Disconnect the diagnosis sensor unit harness connectors.
4. Remove bolts from the diagnosis sensor unit.
INSTALLATION
Installation is in the reverse order of removal.
• After the work is completed, perform self-diagnosis to check that no malfunction is detected. Refer to SRC-
13, "SRS Operation Check".
CAUTION:
• The diagnosis sensor unit must always be installed with the arrow mark " ⇐" pointing toward the
front of the vehicle for proper operation.
ECU DISCRIMINATED NO.
After replacing the diagnosis sensor unit, confirm that the diagnosis sensor unit identification is correct for the
vehicle as equipped. Refer to SRC-15, "
CONSULT-III Function (AIR BAG)".
LHIA0063E
Revision: March 2010 2008 QX56

PRECAUTIONSSRC-93
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004918899
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers, always switch the Ignition OFF, disconnect the battery, and wait at least 3 minutes before performing any service.
Precaution for SRS "AIR BAG" and "SEAT BELT PRE-TENSIONER" Service
INFOID:0000000001735367
• Do not use electrical test equipment to check SRS ci rcuits unless instructed to in this Service Manual.
• Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 min- utes.
For approximately 3 minutes after the cables are remov ed, it is still possible for the air bag and seat belt pre-
tensioner to deploy. Therefore, do not work on any SR S connectors or wires until at least 3 minutes have
passed.
• The air bag diagnosis sensor unit must always be installed with the arrow mark “ ⇐” pointing toward the front
of the vehicle for proper operation. Also check air bag diagnosis sensor unit for cracks, deformities or rust
before installation and replace as required.
• The spiral cable must be aligned with the neutral position since its rotations are limited. Do not attempt to
turn steering wheel or column after removal of steering gear.
• Handle air bag module carefully. Always place driver and front passenger air bag modules with the pad side facing upward and seat mounted front side air bag module standing with the stud bolt side facing down.
• Conduct self-diagnosis to check entire SRS for proper function after replacing any components.
• After air bag inflates, the front instrument panel assembly should be replaced if damaged.
Occupant Classification System PrecautionINFOID:0000000001735368
Replace occupant classification system control uni t and passenger front seat cushion as an assembly.
Revision: March 2010 2008 QX56

ST-4
< PRECAUTION >
PRECAUTIONS
5. When the repair work is completed, return the ignition switch to the ″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of a ll control units using CONSULT-III.
Precaution for Steering SystemINFOID:0000000001534681
• Before disassembly, thoroughly clean the outside of the unit.
• Disassembly should be done in a clean work area. It is im portant to prevent the internal parts from becoming
contaminated by dirt or other foreign matter.
• For easier and proper assembly, place disassembled parts in order on a parts rack.
• Use nylon cloth or paper towels to clean the parts; co mmon shop rags can leave lint that might interfere with
their operation.
• Before inspection or reassembly, carefully clean all parts with a general purpose, non-flammable solvent.
• Before assembly, apply a coat of recommended Genuine NISSAN PSF or equivalent to hydraulic parts. Petroleum jelly may be applied to O-rings and seals. Do not use any grease.
• Replace all gaskets, seals and O-rings. Avoid damaging O-rings, seals and gaskets during installation. Per- form functional tests whenever designated.
Revision: March 2010 2008 QX56

TM-3
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P1752 INPUT CLUTCH SOLENOID .............. ....80
Description .......................................................... ....80
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
80
On Board Diagnosis Logic ......................................80
Possible Cause .......................................................80
DTC Confirmation Procedure ..................................80
Diagnosis Procedure ...............................................80
P1757 FRONT BRAKE SOLENOID ...................82
Description .......................................................... ....82
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
82
On Board Diagnosis Logic ......................................82
Possible Cause .......................................................82
DTC Confirmation Procedure ..................................82
Diagnosis Procedure ...............................................82
P1762 DIRECT CLUTCH SOLENOID ................84
Description .......................................................... ....84
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
84
On Board Diagnosis Logic ......................................84
Possible Cause .......................................................84
DTC Confirmation Procedure ..................................84
Diagnosis Procedure ...............................................84
P1767 HIGH AND LOW REVERSE CLUTCH
SOLENOID .........................................................
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Description .......................................................... ....86
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
86
On Board Diagnosis Logic ......................................86
Possible Cause .......................................................86
DTC Confirmation Procedure ..................................86
Diagnosis Procedure ...............................................86
P1772 LOW COAST BRAKE SOLENOID .........88
Description .......................................................... ....88
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
88
On Board Diagnosis Logic ......................................88
Possible Cause .......................................................88
DTC Confirmation Procedure ..................................88
Diagnosis Procedure ...............................................88
P1774 LOW COAST BRAKE SOLENOID .........90
Description .......................................................... ....90
CONSULT-III Reference Value in Data Monitor
Mode ................................................................... ....
90
On Board Diagnosis Logic ......................................90
Possible Cause .......................................................90
DTC Confirmation Procedure ..................................90
Diagnosis Procedure ...............................................90
MAIN POWER SUPPLY AND GROUND CIR-
CUIT ....................................................................
92
Diagnosis Procedure ........................................... ....92
CLOSED THROTTLE POSITION AND WIDE
OPEN THROTTLE POSITION CIRCUIT ...........
94
CONSULT-III Reference Value in Data Monitor
Mode .................................................................... ....
94
Diagnosis Procedure ...............................................94
BRAKE SIGNAL CIRCUIT ................................95
CONSULT-III Reference Va lue in Data Monitor
Mode .................................................................... ....
95
Diagnosis Procedure ...............................................95
TOW MODE SWITCH .......................................96
Description ...............................................................96
Diagnosis Procedure ...............................................96
A/T SHIFT LOCK SYSTEM ...............................97
Wiring Diagram - A/T Shift Lock System .................97
Terminals And Reference Values ..........................100
Component Description ....................................... ..100
ECU DIAGNOSIS .......................................103
TCM .................................................................103
Reference Value .................................................. ..103
Wiring Diagram — A/T CONTROL SYSTEM — .. ..105
Fail-Safe .............................................................. ..114
DTC Inspection Priority Chart ................................116
DTC No. Index .......................................................116
DTC Alphabetical Index .........................................117
SYMPTOM DIAGNOSIS ............................118
SYSTEM SYMPTOM .......................................118
A/T Check Indicator Lamp Does Not Come On ... ..118
Engine Cannot Be Started in "P" or "N" Position ...118
In "P" Position, Vehicle Moves When Pushed .......119
In "N" Position, Vehicle Moves ..............................119
Large Shock("N" to "D" Position) ...........................121
Vehicle Does Not Creep Backward in "R" Position ..123
Vehicle Does Not Creep Forward in "D" Position ..125
Vehicle Cannot Be Started from D1 ......................128
A/T Does Not Shift: D1→D2 ..................................130
A/T Does Not Shift: D2→ D3 ..................................131
A/T Does Not Shift: D3→ D4 ..................................133
A/T Does Not Shift: D4→ D5 ..................................135
A/T Does Not Perform Lock-up ........................... ..137
A/T Does Not Hold Lock-up Condition ...................139
Lock-up Is Not Released .......................................140
Engine Speed Does Not Return to Idle .................141
A/T Does Not Shift: 5GR → 4GR ........................ ..142
A/T Does Not Shift: 4GR → 3GR ........................ ..144
A/T Does Not Shift: 3GR → 2GR ........................ ..146
A/T Does Not Shift: 2GR → 1GR ........................ ..147
Vehicle Does Not Decelerate By Engine Brake ... ..149
Symptom Table .....................................................151
PRECAUTION ............................................173
PRECAUTIONS ...............................................173
Revision: March 2010 2008 QX56

A/T CONTROL SYSTEMTM-21
< FUNCTION DIAGNOSIS >
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CONTROL SYSTEM DIAGRAM
CAN CommunicationINFOID:0000000001603991
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only. For details, refer to LAN-4,
"System Description".
SENSORS (or SIGNALS)
⇒TCM
⇒ACTUATORS
Transmission range switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Output speed sensor
Vehicle speed signal
Stop lamp switch signal
Input speed sensor
1st position switch signal
4th position switch signal
ATF pressure switch 2 signal
Tow mode switch signal Shift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-III co
mmunication
line
Duet-EA control
CAN system Input clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch sole-
noid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Starter relay
Back-up lamp relay
JSDIA1315GB
Revision: March 2010
2008 QX56

TM-96
< COMPONENT DIAGNOSIS >
TOW MODE SWITCH
TOW MODE SWITCH
DescriptionINFOID:0000000001604165
When tow mode switch is “ON”, tow mode switch signals are sent to TCM from combination meter by CAN
communication line.Then it`s a tow mode condition.
Diagnosis ProcedureINFOID:0000000001604167
1.CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to TM-32, "
CONSULT-III Function (TRANSMISSION)".
Is any malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to TM-38.
NO >> GO TO 2.
2.CHECK POWER SOURCE
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check the voltage between tow mode switch connector M258 terminal 1 and ground.
OK or NG
OK >> INSPECTION END
NG >> GO TO 3.
3.CHECK TOW MODE SWITCH
1. Turn ignition switch “OFF”.
2. Disconnect tow mode switch connector.
3. Check continuity between tow mode switch terminals 1 and 2.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace tow mode switch.
4.DETECT MALFUNCTIONING ITEM
Check the following items. If any items are damaged, repair or replace damaged parts.
• Harness for short or open between combination meter connector terminal 35 and tow mode switch connec- tor terminal 1.
• Harness for short or open between tow mode switch connector terminal 2 and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5.CHECK COMBINATION METER
Check the combination meter. Refer to MWI-4, "
Work Flow".
OK or NG
OK >> INSPECTION END
NO >> Repair or replace damaged parts.
Condition To w m o d e
switch Data (Approx.)
When ignition switch is turned to “ON” ON
0V
OFF Battery voltage
SCIA5156E
Condition Continuity
Tow mode switch “ON” Yes
Tow mode switch “OFF” No
SCIA5584E
Revision: March 2010 2008 QX56

TCM
TM-115
< ECU DIAGNOSIS >
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Even when the electronic circuits are normal, under s pecial 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. Therefore, the customer's vehicle has returned to normal, so handle according to the
“diagnostics flow” (Refer to TM-5, "
Work Flow").
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, th is function controls the A/T to mark driving possible.
Output Speed Sensor
• Signals are input from two systems - from output s peed sensor installed on the transmission and from com-
bination meter so normal driving is possible even if t here is a malfunction in one of the systems. And if output
speed sensor has unusual cases, 5GR is prohibited.
Accelerator Pedal Position Sensor
• If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, 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 according
to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow sys-
tems, 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.
Transmission Range Switch
• In the unlikely event that a malfunction signal enters t he 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” range to make driving possible.
Starter Relay
• The starter relay is switched “OFF”. (Starter starting is disabled.)
Interlock
• If there is an interlock judgment malfunction, the tr ansmission is fixed in 2GR to make driving possible.
NOTE:
When the vehicle is driven fixed in 2GR, a inpu t speed sensor malfunction is displayed, but this is
not a input speed sensor malfunction.
• When the interlock is detected at the 3GR or more, it is locked at the 2GR.
1st Engine Braking
• When there is an 1st 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 driv- ing 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, the engine brake is
not applied in 1GR and 2GR.
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 4GR 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 5GR; if the solenoid is OFF, 4GR.
Revision: March 2010 2008 QX56

TM-174
< PRECAUTION >
PRECAUTIONS
5. When the repair work is completed, return the ignition switch to the ″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of a ll control units using CONSULT-III.
Precaution for On Board Diagnosis (OBD) System of A/T and EngineINFOID:0000000001531485
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
• Be sure to turn the ignition switch “OFF” and disconnect the negative battery cable before any repair
or inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc. Will
cause the MIL to light up.
• Be sure to connect and lock the connectors secure ly after work. A loose (unlocked) connector will
cause the MIL to light up due to an open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
• Be sure to route and secure th e harnesses properly after work. Interference of the harness with a
bracket, etc. May cause the MIL to light up due to a short circuit.
• Be sure to connect rubber tubes properly afte r work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to a malfunction of the EGR system or fuel injection system, etc.
• Be sure to erase the unnecessary malfunction informa tion (repairs completed) from the TCM and
ECM before returning the vehicle to the customer.
PrecautionINFOID:0000000001531486
NOTE:
If any malfunctions occur in the RE5R05A model tr ansmission, replace the entire transmission assem-
bly.
• Before connecting or disconn ecting the TCM harness connec-
tor, turn ignition switch “O FF” and disconnect negative bat-
tery cable. Because battery voltage is applied to TCM even if
ignition switch is turned “OFF”.
• After performing each TROUBLE DIAGNOSIS, perform “DTC
(Diagnostic Trouble Code) CONFIRMATION PROCEDURE”.
If the repair is completed the DTC should not be displayed in the
“DTC CONFIRMATION PROCEDURE”.
• Always use the specified brand of ATF. Refer to MA-12, "
Fluids and Lubricants".
• Use paper rags not cloth rags during work.
• After replacing the ATF, dispose of the waste oil using the methods prescribed by law, ordinance, etc.
• Before proceeding with disassembly, thoroughly clean the outside of the transmission. It is important to pre- vent the internal parts from becoming cont aminated by dirt or other foreign matter.
• Disassembly should be done in a clean work area.
• Use lint-free cloth or towels for wiping parts clean. Common shop rags can leave fibers that could interfere
with the operation of the transmission.
• Place disassembled parts in order for easier and proper assembly.
SEF289H
SEF217U
Revision: March 2010 2008 QX56