2011 INFINITI QX56 engine

SEC-4
ENGINE DOES NOT START WHEN INTELLI-
GENT KEY IS INSIDE OF VEHICLE ...............
148
Description ........................................................... ..148
Diagnosis Procedure .............................................148
STEERING DOES NOT LOCK ........................149
Description ........................................................... ..149
Diagnosis Procedure .............................................149
SECURITY INDICATOR LAMP DOES NOT
TURN ON OR BLINK .......................................
150
Description ........................................................... ..150
Diagnosis Procedure .............................................150
VEHICLE SECURITY SYSTEM CANNOT BE
SET ..................................................................
151
INTELLIGENT KEY ................................................ ..151
INTELLIGENT KEY : Description ..........................151
INTELLIGENT KEY : Diagnosis Procedure ......... ..151
DOOR REQUEST SWITCH ................................... ..151
DOOR REQUEST SWITCH : Description .............151
DOOR REQUEST SWITCH : Diagnosis Proce-
dure ...................................................................... .
151
DOOR KEY CYLINDER ......................................... .152
DOOR KEY CYLINDER : Description ...................152
DOOR KEY CYLINDER : Dia gnosis Procedure .. .152
VEHICLE SECURITY ALARM DOES NOT
ACTIVATE ...................................................... ..
153
Description ........................................................... .153
Diagnosis Procedure .............................................153
PANIC ALARM FUNCTION DOES NOT OP-
ERATE ..............................................................
154
Description ........................................................... .154
Diagnosis Procedure .............................................154
REMOVAL AND INSTALLATION .............155
NATS ANTENNA AMP. .................................. ..155
Removal and Installation ...................................... .155
PUSH-BUTTON IGNITION SWITCH ................156
Exploded View ..................................................... .156
Removal and Installation .......................................156
Revision: 2010 May2011 QX56

PRECAUTIONSSEC-5
< PRECAUTION > [WITH INTELLIGENT KEY SYSTEM]
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006226148
The Supplemental Restraint System such as “A IR 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 whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision that would result in air ba g 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 “SRS AIR BAG”.
 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 Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the
ignition ON or engine running, DO NOT use air or electric 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 Necessary for Steering Wh eel Rotation after Battery Disconnect
INFOID:0000000006226149
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect both battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the batte ry disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wil l remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

COMPONENT PARTSSEC-9
< SYSTEM DESCRIPTION > [WITH INTELLIGENT KEY SYSTEM]
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Then, when the power supply position is turned ON, BCM performs ID verification between BCM and ECM. If
the ID verification result is OK, ECM can start engine.
ECMINFOID:0000000006226155
ECM controls the engine.
When power supply position is turned ON, BCM starts communication with ECM and performs the ID verifica-
tion between BCM and ECM.
If the verification result is OK, the engine can start. If the verification result is NG, the engine can not start.
IPDM E/RINFOID:0000000006226156
IPDM E/R has steering lock relay, starter relay and starte r control relay inside. Steering lock relay is used for
the steering lock/unlock function. Starter relay and star ter control relay are used for the engine starting func-
tion. IPDM E/R controls these relays while communicating with BCM.
NATS Antenna Amp.INFOID:0000000006226157
The ID verification is performed between BCM and transponder in Intelligent Key via NATS antenna amp.
when Intelligent Key backside is contacted to push-button i gnition switch in case that Intelligent Key battery is
discharged. If the ID verification result is OK, the release of steering lock and the operation of starting engine
is available.
TCMINFOID:0000000006226158
TCM transmits the shift position signal (P/N position) to BCM and IPDM E/R. And further, TCM transmits the
shift position signal (P/N position) to BCM via CAN communication.
BCM confirms the A/T shift selector position with the following 5 signals.
 P position signal from A/T shift selector (detention switch)
 P/N position signal from TCM
 P position signal from IPDM E/R (CAN)
 P/N position signal from IPDM E/R (CAN)
 P/N position signal from TCM (CAN)
IPDM E/R confirms the A/T shift sele ctor position with the following 3 signals.
 P position signal from A/T shift selector (detention switch)
 P/N position signal from TCM
 P/N position signal from BCM (CAN)
Combination MeterINFOID:0000000006226159
Combination meter transmits the vehicle speed signal to BCM via CAN communication.
BCM also receives the vehicle speed signal from ABS ac tuator and electric unit (control unit) via CAN commu-
nication. BCM compares both signals to detect the vehicle speed.
Door SwitchINFOID:0000000006226160
Door switch detects door open/close condition and then transmits ON/OFF signal to BCM.
Hood SwitchINFOID:0000000006226161
Hood switch detects that hood is open, and then transmits the signal to IPDM E/R. IPDM E/R transmits hood
switch signal to BCM via CAN communication.
Inside Key AntennaINFOID:0000000006226162
Inside key antenna detects whether Intelligent Key is inside the vehicle, and transmits the signal to BCM.
Three inside key antennas are installed in t he instrument center, console and luggage room.
Intelligent KeyINFOID:0000000006226163
Each Intelligent key has an individual electronic ID , and transmits the ID signal by request from BCM.
Carrying the Intelligent Key whose ID is registered in BCM, the driver can performs door lock/unlock operation
and push-button ignition switch operation.
Revision: 2010 May2011 QX56

SEC-10
< SYSTEM DESCRIPTION >[WITH INTELLIGENT KEY SYSTEM]
COMPONENT PARTS
Push-button Ignition Switch
INFOID:0000000006226165
Push-button ignition switch detects that push-button is pressed, and then transmits the signal to BCM. BCM
changes the power supply position with the operation of push-button ignition switch. BCM maintains the power
supply position status while push-button is not operated.
Remote Keyless Entry ReceiverINFOID:0000000006226166
Remote keyless entry receiver receives each button oper ation signal and electronic key ID signal from Intelli-
gent Key, and then transmits the signal to BCM.
Security Indicator LampINFOID:0000000006226167
Security indicator lamp is located on combination meter.
Security indicator lamp blinks when power supply position is any position other than ON to warn that INFINITI
VEHICLE IMMOBILIZER SYSTEM-N ATS [IVIS (NATS)] is on board.
Starter Control RelayINFOID:0000000006226170
Engine starting system functions by controlling both starter relay and starter control relay.
Both relays are integrated in IPDM E/R. Starter relay is controlled by BCM, and starter control relay is con-
trolled by IPDM E/R on request from BCM.
IPDM E/R transmits starter relay and starter control relay status signal to BCM via CAN communication.
Starter RelayINFOID:0000000006226171
Engine starting system functions by controlling both starter relay and starter control relay.
Both relays are integrated in IPDM E/R. Starter relay is controlled by BCM, and starter control relay is con-
trolled by IPDM E/R on request from BCM.
IPDM E/R transmits starter relay and starter control relay status signal to BCM via CAN communication.
Steering Lock RelayINFOID:0000000006226172
Steering lock relay is integrated in IPDM E/R, and supplies power source to steering lock unit.
When IPDM E/R receives the steering lock relay ON request signal from BCM, IPDM E/R turns ON steering
lock relay and then transmits the steering lock relay condition signal to BCM.
Steering Lock UnitINFOID:0000000006226173
Steering lock unit performs steering lock/unlock operation on request from BCM, and power source is supplied
from steering lock relay integrated in IPDM E/R.
When push-button ignition switch is pressed while the In telligent Key is inside the vehicle, BCM performs the
ID verification with steering lock unit. Steering lock unit releases the steering lock based on the result of the ID
verification.
Steering lock unit has 2 switches (steering lock status switch and steering unlock status switch) inside. BCM
judges the steering lock/unlock condition by comparing these switch signals and steering lock unit status sig-
nal transmitted from IPDM E/R via CAN communication.
Stop Lamp SwitchINFOID:0000000006226174
Stop lamp switch detects that brake pedal is depressed, and then transmits the signal to BCM.
Transmission Range SwitchINFOID:0000000006226175
Transmission range switch is integrated in A/T asse mbly, and detects the A/T shift selector position.
TCM receives the transmission range switch signal and then transmits the P/N position signal to BCM and
IPDM E/R.
BCM confirms the A/T shift selector position with the following 5 signals.
 P position signal from A/T shift selector (detention switch)
 P/N position signal from TCM
 P position signal from IPDM E/R (CAN)
 P/N position signal from IPDM E/R (CAN)
 P/N position signal from TCM (CAN)
IPDM E/R confirms the A/T shift select or position with the following 3 signals.
Revision: 2010 May2011 QX56

SEC-12
< SYSTEM DESCRIPTION >[WITH INTELLIGENT KEY SYSTEM]
SYSTEM
SYSTEM
INTELLIGENT KEY SYSTEM
/ENGINE START FUNCTION
INTELLIGENT KEY SYSTEM/ENGINE START FUNCTION : System Diagram
INFOID:0000000006226178
INTELLIGENT KEY SYSTEM/ENGINE STAR T FUNCTION : System Description
INFOID:0000000006226179
SYSTEM DESCRIPTION
 The engine start function of Intelligent Key system makes it possible to start and stop the engine without
using the key, based on the electronic ID verification. The electronic ID verification is performed between
BCM and Intelligent Key when the push-button ignition swit ch is pressed while the Intelligent Key is within
the detection area of inside key antenna.
NOTE:
The driver should carry the Intelligent Key at all times.
 Intelligent Key has 2 IDs [Intelligent Key ID and IVIS (NATS) ID]. It can perform the door lock/unlock opera-
tion and the push-button ignition switch operation when the registered Intelligent Key is carried.
 When Intelligent Key battery is discharged, engine c an be started by operating push-button ignition switch
after contacting Intelligent Key backside to push-button igni tion switch. At that time, the IVIS (NATS) ID veri-
fication is performed.
 If the ID is successfully verified, when push-button igni tion switch is pressed, steering lock is released and
the engine can be started.
JMKIA5239GB
Revision: 2010 May2011 QX56

SYSTEMSEC-13
< SYSTEM DESCRIPTION > [WITH INTELLIGENT KEY SYSTEM]
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 Up to 4 Intelligent Keys can be registered (Includi ng the standard Intelligent Key) upon request from the cus-
tomer.
NOTE:
Refer to DLK-18, "
INTELLIGENT KEY SYSTEM : System Description" for any functions other than engine
start function of Intelligent Key system.
PRECAUTIONS FOR INTELLIGENT KEY SYSTEM
The transponder [the chip for IVIS (NATS) ID verification] is integrated into the Intelligent Key. (For the
conventional models, it is integrated into the mech anical key.) Therefore, ID verification cannot be per-
formed by mechanical key only.
In that case, the IVIS (NATS) ID verification can be performed when Intelligent Key backside is con-
tacted to push-button ignition switch. If verification result is OK, engine can be started.
OPERATION WHEN INTELLIGENT KEY IS CARRIED
1. When the push-button ignition switch is pressed, the BCM activates the inside key antenna and transmits
the request signal to the Intelligent Key.
2. The Intelligent Key receives the request signal and transmits the Intelligent Key ID signal to the BCM.
3. BCM receives the Intelligent Key ID signal via remote keyless entry receiver and verifies it with the regis-
tered ID.
4. BCM transmits the unlock signal to steering lock unit and IPDM E/R if the verification results are OK.
5. IPDM E/R turns the steering lock relay ON and supplies power supply to the steering lock unit.
6. The steering lock releases.
7. BCM transmits the power supply stop signal to IPDM E/R when detecting that the steering lock is in the
unlock condition.
8. IPDM E/R turns the steering lock relay OFF and stops power supply to the steering lock unit.
9. BCM turns ACC relay ON and transmits the ignition power supply ON signal to IPDM E/R.
10. IPDM E/R turns the ignition relay ON and starts the ignition power supply.
11. BCM detects that the selector lever position and brake pedal operating condition.
12. BCM transmits the starter request signal to IPDM E/R and turns the starter relay in IPDM E/R ON if BCM
judges that the engine start condition* is satisfied.
13. IPDM E/R turns the starter control relay ON when receiving the starter request signal.
14. Power supply is supplied through the starter relay and the starter control relay to operate the starter motor. CAUTION:
If a malfunction is detected in the Intelligent Key system, the “KEY” warning lamp in the combina-
tion meter illuminates. At that time, the engine cannot be started.
15. When BCM receives feedback signal from ECM indicati ng that the engine is started, the BCM transmits a
stop signal to IPDM E/R and stops cranking by turning OFF the starter motor relay. (If engine start is
unsuccessful, cranking stops automatically within 5 seconds.)
CAUTION:
When the Intelligent Key is carried outside of th e vehicle (inside key antenna detection area) while
the power supply is in the ACC or ON position, even if the engine start condition* is satisfied, the
engine cannot be started.
*: For the engine start condition, refer to “POWER SUPPLY POSITION CHANGE TABLE BY PUSH-BUTTON
IGNITION SWITCH OPERATION”.
OPERATION RANGE
Engine can be started when Intelligent Key is inside the vehicle. However, sometimes engine may not start
when Intelligent Key is on instrument panel or in glove box.
ENGINE START OPERATION WHEN INTELLIGENT KEY IS CONTACTED TO PUSH-BUTTON IG-
NITION SWITCH
When Intelligent Key battery is discharged, the IVIS (NATS) ID verification between transponder in Intelligent
Key and BCM is performed when Intelligent Key backside is contacted to push-button ignition switch. If the
verification result is OK, engine can be started.
STEERING LOCK OPERATION
Steering is locked by steering lock unit when any of the following conditions are met.
Revision: 2010 May2011 QX56

SEC-14
< SYSTEM DESCRIPTION >[WITH INTELLIGENT KEY SYSTEM]
SYSTEM
 When ignition switch is in the OFF position, selector le
ver is in the P position, and any of the following condi-
tions are met.
- Closing door
- Opening door
- Door is locked using door request switch
- Door is locked using Intelligent Key
 When BCM power consumption control system is rel eased by meeting any of the following conditions.
- Opening any door
- Operating door lock using door request switch
- Operating door lock using Intelligent Key
POWER SUPPLY POSITION CHANGE TABLE BY PUSH-BUTTON IGNITION SWITCH OPERA-
TION
The power supply position changing operation can be performed with the following operations.
NOTE:
 When an Intelligent Key is within the detection area of inside key antenna and when Intelligent Key backside
is contacted to push-button ignition switch, it is equivalent to the operations below.
 When starting the engine, the BCM monitors under the engine start conditions,
- Brake pedal operating condition
- Selector lever position
- Vehicle speed
Vehicle speed: less than 4 km/h (2.5 MPH)
Vehicle speed: 4 km/h (2.5 MPH) or more
Emergency stop operation
 Press and hold the push-button ignition switch for 2 seconds or more.
 Press the push-button ignition switch 3 times or more within 1.5 seconds.
INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS
Power supply position Engine start/stop condition
Push-button ignition switch
operation frequency
Selector lever Brake pedal operation
condition
LOCK → ACC — Not depressed 1
LOCK → ACC → ON — Not depressed 2
LOCK → ACC → ON → OFF — Not depressed 3
LOCK → START
ACC → START
ON → START P or N position Depressed 1
Engine is running → OFF — — 1
Power supply position Engine start/stop condition
Push-button ignition switch
operation frequency
Selector lever Brake pedal operation
condition
Engine is running → ACC — — Emergency stop operation
Engine stall return operation while
driving N position Not depressed 1
Revision: 2010 May2011 QX56

SYSTEMSEC-15
< SYSTEM DESCRIPTION > [WITH INTELLIGENT KEY SYSTEM]
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INFINITI VEHICLE IMMOBILIZE R SYSTEM-NATS : System DiagramINFOID:0000000006226180
INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS : System DescriptionINFOID:0000000006226181
SYSTEM DESCRIPTION
 The INFINITI VEHICLE IMMOBILIZER SYSTEM-NAT S [IVIS (NATS)] prevents the engine from being
started by Intelligent Key whose ID is not registered to the vehicle (BCM). It has higher protection against
auto theft involving the duplication of mechanical keys.
 The ignition key integrated in the Intelligent Key cannot start the engine. When the Intelligent Key battery is
discharged, the IVIS (NATS) ID verification is performed between the transponder integrated with Intelligent
Key and BCM via NATS antenna amp. when the Intelligent Key backside is contacted to push-button ignition
switch. If the verification results are OK, the engine start operation can be performed by the push-button igni-
tion switch operation.
 Locate the security indicator lamp and apply the anti-t heft system equipment sticker that warns that the IVIS
(NATS) is on board the model.
 Security indicator lamp always blinks when the pow er supply position is any position other than ON.
 Up to 4 Intelligent Keys can be registered (including the standard ignition key) upon request from the owner.
 Specified registration is required when replacing ECM, BCM or Intelligent Key. For the registration proce-
dures, refer to CONSULT-III O peration Manual NATS-IVIS/NVIS.
 Possible symptom of IVIS (NATS) malfunction is “Engine cannot start”. The engine can not be started
because of other than IVIS (NATS) malfunction, so start the trouble diagnosis according to SEC-48, "
Work
Flow".
 If ECM other than genuine part is installed, the engi ne cannot be started. For ECM replacement procedure,
refer to EC-143, "
Work Procedure".
JMKIA5734GB
Revision: 2010 May2011 QX56