2008 INFINITI QX56 engine

HEATER & COOLING UNIT ASSEMBLYVTL-17
< ON-VEHICLE REPAIR >
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1. Move the two front seats to the rear most position on the seat track.
2. Disconnect the battery negative terminal and battery positive terminal.
3. Discharge the refrigerant from the A/C system. Refer to HA-20, "
HFC-134a (R-134a) Service Procedure".
4. Drain the coolant from the engine cooling system. Refer to CO-11, "
Changing Engine Coolant".
5. Disconnect the front heater hoses from the front heater core.
6. Disconnect the high/low pressure pipes from the front expansion valve.
7. Remove the instrument panel and console panel. Refer to IP-12, "
Removal and Installation".
8. Remove the steering column. Refer to ST-20, "
Removal and Installation".
9. Disconnect the instrument panel wire harness at t he RH and LH in-line connector brackets, and the fuse
block (J/B) electrical connectors. Refer to PG-9, "
Wiring Diagram — Battery Power Supply —".
10. Disconnect the steering member from each side of the vehicle body.
11. Remove the front heater and cooling unit assembly with it attached to the steering member, from the vehi- cle.
CAUTION:
Use care not to damage the seats and interior trim panels when removing the front heater and
cooling unit assembly with it at tached to the steering member.
12. Remove the front heater and cooling uni t assembly from the steering member.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com-
pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the specified coolant mixture. Refer to CO-11, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to HA-20, "
HFC-134a (R-134a) Service Procedure".
REAR HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Discharge the refrigerant from the A/C system. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Drain the coolant from the engine cooling system. Refer to CO-11, "
Changing Engine Coolant".
3. Remove the luggage side finisher lower RH. Refer to INT-19, "
Removal and Installation".
4. Disconnect the rear heater core hoses from the rear heater core.
5. Disconnect the rear A/C pipes from the rear expansion valve.
6. Disconnect the following electrical connectors: • Rear blower motor
• Rear variable blower control
• Rear air mix door motor
7. Disconnect the ducts from the rear heater and cooling unit assembly.
8. Remove the rear heater and cooling unit assembly.
Installation
Installation is in the reverse order of removal.
CAUTION:
• Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply com- pressor oil to it when installing it.
• After charging the refrigerant, check for leaks.
NOTE:
• Fill the engine cooling system with the specified coolant mixture. Refer to CO-11, "
Changing Engine Cool-
ant".
• Recharge the A/C system. Refer to HA-20, "
HFC-134a (R-134a) Service Procedure".
Revision: March 2010 2008 QX56

VTL-20
< ON-VEHICLE REPAIR >
HEATER CORE
5. Remove the heater core.NOTE:
If the in-cabin microfilters are c ontaminated from coolant leaking
from the heater core, replace the in-cabin microfilters with new
ones before installing the new heater core.
Installation
Installation is in the reverse order of removal.
REAR HEATER CORE
Removal
1. Partially drain the engine cooling system. Refer to CO-11, "Changing Engine Coolant".
2. Remove the luggage side finisher lower RH. Refer to INT-19, "
Removal and Installation".
3. Disconnect the rear heater hoses from the heater core.
4. Remove the rear heater core bracket.
5. Remove the heater core.
Installation
Installation is in the reverse order of removal.
LJIA0134E
Revision: March 2010 2008 QX56

WCS-14
< FUNCTION DIAGNOSIS >
DIAGNOSIS SYSTEM (METER)
X: Applicable
Display item [Unit]MAIN
SIGNALS SELECTION
FROM MENU Description
SPEED METER [km/h] or [mph] X X Displays the value of vehicle speed signal.
SPEED OUTPUT [km/h] or [mph] X XDisplays the value of vehicle speed signal, which is transmitted to
each unit with
CAN communication.
TACHO METER [rpm] XX Displays the value of engine speed signal, which is input from ECM.
FUEL METER [lit.] XXDisplays the value, which processes a resistance signal from fuel
gauge.
W TEMP METER [ °C] or [° F] X XDisplays the value of engine coolant temperature signal, which is in-
put from ECM.
ABS W/L [ON/OFF] X Displays [ON/OFF] condition of ABS warning lamp.
VDC/TCS IND [ON/OFF] X Displays [ON/OFF] condition of VDC OFF indicator lamp.
SLIP IND [ON/OFF] X Displays [ON/OFF] condition of SLIP indicator lamp.
BRAKE W/L [ON/OFF] X Displays [ON/OFF] condition of brake warning lamp.*
DOOR W/L [ON/OFF] X Displays [ON/OFF] condition of door warning lamp.
TRUNK W/L [ON/OFF] X Displays [ON/OFF] condition of glass hatch warning lamp.
HI-BEAM IND [ON/OFF] X Displays [ON/OFF] condition of high beam indicator.
TURN IND [ON/OFF] X Displays [ON/OFF] conditio n of turn indicator.
OIL W/L [ON/OFF] X Displays [ON/OFF] condition of oil pressure warning lamp.
C-ENG W/L [ON/OFF] X Displays [ON/OFF] condition of malfunction indicator lamp.
CRUISE IND [ON/OFF] X Displays [ON/OFF] condition of CRUISE indicator.
SET IND [ON/OFF] X Displays [ON/OFF] condition of SET indicator.
AT CHECK W/L [ON/OFF] X Displays [ON/OFF] condition of AT CHECK warning lamp.
FUEL W/L [ON/OFF] XX Displays [ON/OFF] condition of low-fuel warning lamp.
AIR PRES W/L [ON/OFF] X Displays [ON/OFF] condition of tire pressure warning lamp.
KEY G W/L [ON/OFF] X Displays [ON/OFF] condition of key green warning lamp.
KEY R W/L [ON/OFF] X Displays [ON/OFF] condition of key red warning lamp.
KEY KNOB W/L [ON/OFF] X Displays [ON/OFF] condition of key knob warning lamp.
M RANGE SW [ON/OFF] XX Displays [ON/OFF] condition of manual mode range switch.
NM RANGE SW [ON/OFF] XXDisplays [ON/OFF] condition of except for manual mode range
switch.
AT SFT UP SW [ON/OFF] XX Displays [ON/OFF] condition of A/T shift-up switch.
AT SFT DWN SW [ON/OFF] XX Displays [ON/OF F] condition of A/T shift-down switch.
DISTANCE [km] or [mile] XXDisplays the value, which is calculated by vehicle speed signal, fuel
gauge and fuel consumption from ECM.
BUZZER [ON/OFF] XX Displays [ON/ OFF] condition of buzzer.
BRAKE SW [ON/OFF] X Indicates [ON/OFF] condition of parking brake switch.
AT-M GEAR [1, 2, 3, 4, 5] XX Indicates [1, 2, 3, 4, 5] condition of A/T manual mode gear position.
P RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift P range indicator.
R RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift R range indicator.
N RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift N range indicator.
D RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift D range indicator.
4 RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift 4 range indicator.
3 RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift 3 range indicator.
2 RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift 2 range indicator.
1 RANGE IND [ON/OFF] XX Indicates [ON/OFF] condition of A/T shift 1range indicator.
Revision: March 2010 2008 QX56

WCS
COMBINATION METERWCS-49
< ECU DIAGNOSIS >
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DTC IndexINFOID:0000000004871171
Function Specifications
Speedometer
Zero indication.
Tachometer
Fuel gauge
Engine coolant temperature gauge
Engine oil pressure gauge
Voltage gauge
A/T oil temperature gauge
Illumination control
Meter illumination Change to nighttime mode when communication is lost.
Segment LCD Odometer
Freeze current indication.
A/T position Display turns off.
Buzzer Buzzer turns off.
Warning lamp/indicator lamp ABS warning lamp
Lamp turns on when communication is lost.
Brake warning lamp
VDC OFF indicator lamp
SLIP indicator lamp
A/T CHECK warning lamp
Lamp turns off when communication is lost.
Oil pressure/coolant temperature
warning lamp
Light indicator
Malfunction indicator lamp
Master warning lamp
Air bag warning lamp
High beam indicator
Turn signal indicator lamp
CRUISE indicator lamp
Driver and passenger seat belt warn-
ing lamp
Lamp turns off when disconnected.
Charge warning lamp
Security indicator lamp
4WD indicator lamp
ATP indicator lamp
CK SUSP warning lamp
Low tire pressu
re warning lamp Lamp will flash every second for 1 minute and then stay on con-
tinuously thereafter.
CONSULT-III display
MalfunctionReference
page
CAN COMM CIRC
[U1000] Malfunction is detected in CAN communication.
CAUTION:
Even when there is no ma
lfunction on CAN communication system, malfunction may be
misinterpreted when battery has low voltag e (when maintaining 7 - 8 V for about 2 sec-
onds) or 10A fuse [No. 19, located in the fuse block (J/B)] is disconnected. MWI-28
VEHICLE SPEED
CIRC
[B2205]Malfunction is detected when an erroneous speed signal is input.
CAUTION:
Even when there is no malfunction on speed signal system, malfunction may be misin-
terpreted when battery has low voltage (whe
n maintaining 7 - 8 V for about 2 seconds). MWI-29
Revision: March 2010
2008 QX56

WCS
BCM (BODY CONTROL MODULE)WCS-51
< ECU DIAGNOSIS >
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BCM (BODY CONTROL MODULE)
Reference ValueINFOID:0000000004871172
VALUES ON THE DIAGNOSIS TOOL
Monitor Item Condition Value/Status
AIR COND SW A/C switch OFF
OFF
A/C switch ON ON
AUT LIGHT SYS Outside of the room is dark
OFF
Outside of the room is bright ON
AUTO LIGHT SW Lighting switch OFF
OFF
Lighting switch AUTO ON
BACK DOOR SW Back door closed
OFF
Back door opened ON
CDL LOCK SW Door lock/unlock switch does not operate
OFF
Press door lock/unlock switch to the LOCK side ON
CDL UNLOCK SW Door lock/unlock switch does not operate
OFF
Press door lock/unlock switch to the UNLOCK side ON
DOOR SW-AS Front door RH closed
OFF
Front door RH opened ON
DOOR SW-DR Front door LH closed
OFF
Front door LH opened ON
DOOR SW-RL Rear door LH closed
OFF
Rear door LH opened ON
DOOR SW-RR Rear door RH closed
OFF
Rear door RH opened ON
ENGINE RUN Engine stopped
OFF
Engine running ON
FR FOG SW Front fog lamp switch OFF
OFF
Front fog lamp switch ON ON
FR WASHER SW Front washer switch OFF
OFF
Front washer switch ON ON
FR WIPER LOW Front wiper switch OFF
OFF
Front wiper switch LO ON
FR WIPER HI Front wiper switch OFF
OFF
Front wiper switch HI ON
FR WIPER INT Front wiper switch OFF
OFF
Front wiper switch INT ON
FR WIPER STOP Any position other than front wiper stop position
OFF
Front wiper stop position ON
HAZARD SW When hazard switch is not pressed
OFF
When hazard switch is pressed ON
LIGHT SW 1ST Lighting switch OFF
OFF
Lighting switch 1st ON
Revision: March 2010 2008 QX56

WCS-52
< ECU DIAGNOSIS >
BCM (BODY CONTROL MODULE)
HEADLAMP SW1Headlamp switch OFF OFF
Headlamp switch 1st
ON
HEADLAMP SW2 Headlamp switch OFF
OFF
Headlamp switch 1st ON
HI BEAM SW High beam switch OFF
OFF
High beam switch HI ON
IGN ON SW Ignition switch OFF or ACC
OFF
Ignition switch ON ON
IGN SW CAN Ignition switch OFF or ACC
OFF
Ignition switch ON ON
INT VOLUME Wiper intermittent dial is in a dial position 1 - 7 1 - 7
I-KEY LOCK LOCK button of Intelligent Key is not pressed
OFF
LOCK button of Intelligent Key is pressed ON
I-KEY UNLOCK UNLOCK button of Intelligent Key is not pressed
OFF
UNLOCK button of Intelligent Key is pressed ON
KEY ON SW Mechanical key is removed from key cylinder
OFF
Mechanical key is inserted to key cylinder ON
OIL PRESS SW • Ignition switch OFF or ACC
• Engine running
OFF
Ignition switch ON ON
PASSING SW Other than lighting switch PASS
OFF
Lighting switch PASS ON
REAR DEF SW Rear window defogger switch OFF
OFF
Rear window defogger switch ON ON
RR WASHER SW Rear washer switch OFF
OFF
Rear washer switch ON ON
RR WIPER INT Rear wiper switch OFF
OFF
Rear wiper switch INT ON
RR WIPER ON Rear wiper switch OFF
OFF
Rear wiper switch ON ON
RR WIPER STOP Rear wiper stop position
OFF
Other than rear wiper stop position ON
TAIL LAMP SW Lighting switch OFF
OFF
Lighting switch 1ST ON
TRNK OPNR SW When back door opener switch is not pressed
OFF
When back door opener switch is pressed ON
TURN SIGNAL L Turn signal switch OFF
OFF
Turn signal switch LH ON
TURN SIGNAL R Turn signal switch OFF
OFF
Turn signal switch RH ON
VEHICLE SPEED While driving Equivalent to speedometer reading
Monitor Item
Condition Value/Status
Revision: March 2010 2008 QX56

WCS
BCM (BODY CONTROL MODULE)WCS-63
< ECU DIAGNOSIS >
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DTC Inspection Priority ChartINFOID:0000000004871177
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
DTC IndexINFOID:0000000004871178
NOTE: Details of time display
• CRNT: Displays when there is a malfunction now or after returning to the normal condition until turning igni-
tion switch OFF → ON again.
• 1 - 39: Displayed if any previous ma lfunction is present when current conditi on is normal. It increases like 1
→ 2 → 3...38 → 39 after returning to the normal condition whenever ignition switch OFF → ON. The counter
remains at 39 even if the number of cycles exceeds it. It is counted from 1 again when turning ignition switch
OFF → ON after returning to the normal condi tion if the malfunction is detected again.
Display contents of CONSULT Fail-safe Cancellation
U1000: CAN COMM CIRCUIT I nhibit engine crankingWhen the BCM re-establishes communication with the other mod-
ules.
U1010: CONTROL UNIT (CAN) Inhibit engine cranking When the BCM re-start communicating with the other modules.
Priority DTC
1 • U1000: CAN COMM CIRCUIT
• U1010: CONTROL UNIT (CAN)
2 • B2190: NATS ANTENNA AMP
• B2191: DIFFERENCE OF KEY
• B2192: ID DISCORD BCM-ECM
• B2193: CHAIN OF BCM-ECM
• B2013: STRG COMM 1
• B2552: INTELLIGENT KEY
• B2590: NATS MALFUNCTION
3 • C1729: VHCL SPEED SIG ERR
• C1735: IGNITION SIGNAL
4 • C1704: LOW PRESSURE FL
• C1705: LOW PRESSURE FR
• C1706: LOW PRESSURE RR
• C1707: LOW PRESSURE RL
• C1708: [NO DATA] FL
• C1709: [NO DATA] FR
• C1710: [NO DATA] RR
• C1711: [NO DATA] RL
• C1712: [CHECKSUM ERR] FL
• C1713: [CHECKSUM ERR] FR
• C1714: [CHECKSUM ERR] RR
• C1715: [CHECKSUM ERR] RL
• C1716: [PRESSDATA ERR] FL
• C1717: [PRESSDATA ERR] FR
• C1718: [PRESSDATA ERR] RR
• C1719: [PRESSDATA ERR] RL
• C1720: [CODE ERR] FL
• C1721: [CODE ERR] FR
• C1722: [CODE ERR] RR
• C1723: [CODE ERR] RL
• C1724: [BATT VOLT LOW] FL
• C1725: [BATT VOLT LOW] FR
• C1726: [BATT VOLT LOW] RR
• C1727: [BATT VOLT LOW] RL
Revision: March 2010
2008 QX56

WCS-68
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004857542
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 severity 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 inopera tive, 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 unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harn esses can be identified 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 Unit or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or electri c 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 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation After Battery Disconnect
INFOID:0000000004857543
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NATS (NISSAN ANTI-THEFT SYS-
TEM).
• Remove and install all control units after disconnecting both battery cables with the ignition knob in the
″LOCK ″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NATS, an electrically controlled steering lock mech-
anism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery pow er is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC ″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be rotated.
4. Perform the necessary repair operation.
Revision: March 2010 2008 QX56