2008 INFINITI QX56 Electrical

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-41
< BASIC INSPECTION >
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Circuit InspectionINFOID:0000000001539227
DESCRIPTION
• In general, testing electrical circuits is an easy task if it is approached in a logical and organized method. Before beginning it is important to have all available information on the system to be tested. Also, get a thor-
ough understanding of system operation. Then you will be able to use the appropriate equipment and follow
the correct test procedure.
• You may have to simulate vehicle vibrations while te sting electrical components. Gently shake the wiring
harness or electrical component to do this.
NOTE:
Refer to GI-35, "
How to Check Terminal" to probe or check terminal.
TESTING FOR “OPENS” IN THE CIRCUIT
Before you begin to diagnose and test the system, you should rough sketch a schematic of the system. This
will help you to logically walk through the diagnosis process. Drawing the sketch will also reinforce your work-
ing knowledge of the system.
Continuity Check Method
The continuity check is used to find an open in the circui t. The digital multimeter (DMM) set on the resistance
function will indicate an open circuit as over limit (no beep tone or no ohms symbol). Make sure to always start
with the DMM at the highest resistance level.
To help in understanding the diagnosis of open circui ts, please refer to the previous schematic.
• Disconnect the battery negative cable.
• Start at one end of the circuit and work your way to the other end. (At the fuse block in this example)
• Connect one probe of the DMM to the fuse block terminal on the load side.
• Connect the other probe to the fuse block (power) side of SW1. Little or no resistance will indicate that por-
tion of the circuit has good continuity. If there were an open in the circuit, the DMM would indicate an over
limit or infinite resistance condition. (point A)
• Connect the probes between SW1 and the relay. Little or no resistance will indicate that portion of the circuit
has good continuity. If there were an open in the circuit, t he DMM would indicate an over limit or infinite resis-
tance condition. (point B)
• Connect the probes between the relay and the solenoid. Little or no resistance will indicate that portion of the
circuit has good continuity. If there were an open in the ci rcuit, the DMM would indicate an over limit or infi-
nite resistance condition. (point C)
Any circuit can be diagnosed using the approach in the previous example.
Voltage Check Method
To help in understanding the diagnosis of open circuits please refer to the previous schematic.
In any powered circuit, an open can be found by methodica lly checking the system for the presence of voltage.
This is done by switching the DMM to the voltage function.
• Connect one probe of the DMM to a known good ground.
• Begin probing at one end of the circuit and work your way to the other end.
• With SW1 open, probe at SW1 to check for voltage. voltage; open is further down the circuit than SW1.
OPEN A circuit is open when there is no continuity through a section of the circuit.
SHORT There are two types of shorts.
• SHORT CIRCUIT
When a circuit contacts another circuit and causes the normal resistance to
change.
• SHORT TO GROUND When a circuit contacts a ground source and grounds the circuit.
SGI846-A
Revision: March 2010 2008 QX56

GI-42
< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
no voltage; open is between fuse block and SW1 (point A).
• Close SW1 and probe at relay. voltage; open is further down the circuit than the relay.
no voltage; open is between SW1 and relay (point B).
• Close the relay and probe at the solenoid. voltage; open is further down the circuit than the solenoid.
no voltage; open is between relay and solenoid (point C).
Any powered circuit can be diagnosed using the approach in the previous example.
TESTING FOR “SHORTS” IN THE CIRCUIT
To simplify the discussion of shorts in the system, please refer to the following schematic.
Resistance Check Method
• Disconnect the battery negative cable and remove the blown fuse.
• Disconnect all loads (SW1 open, relay disconnected and solenoid disconnected) powered through the fuse.
• Connect one probe of the DMM to the load side of the fuse terminal. Connect the other probe to a known good ground.
• With SW1 open, check for continuity. continuity; short is between fuse terminal and SW1 (point A).
no continuity; short is further down the circuit than SW1.
• Close SW1 and disconnect the relay. Put probes at the load side of fuse terminal and a known good ground. Then, check for continuity.
continuity; short is between SW1 and the relay (point B).
no continuity; short is further down the circuit than the relay.
• Close SW1 and jump the relay contacts with jumper wire. Put probes at the load side of fuse terminal and a known good ground. Then, check for continuity.
continuity; short is between relay and solenoid (point C).
no continuity; check solenoid, retrace steps.
Voltage Check Method
• Remove the blown fuse and disconnect all loads (i.e. SW1 open, relay disconnected and solenoid discon-
nected) powered through the fuse.
• Turn the ignition key to the ON or START position. Verify battery voltage at the battery + side of the fuse ter- minal (one lead on the battery + terminal side of the fuse block and one lead on a known good ground).
• With SW1 open and the DMM leads across both fuse terminals, check for voltage. voltage; short is between fuse block and SW1 (point A).
no voltage; short is further down the circuit than SW1.
• With SW1 closed, relay and solenoid disconnected and the DMM leads across both fuse terminals, check for voltage.
voltage; short is between SW1 and the relay (point B).
no voltage; short is further down the circuit than the relay.
• With SW1 closed, relay contacts jumped with fused jumper wire check for voltage. voltage; short is down the circuit of the relay or between the relay and the disconnected solenoid (point C).
no voltage; retrace steps and check power to fuse block.
GROUND INSPECTION
• Ground connections are very important to the proper operation of electrical and electronic circuits. Ground
connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can
become an unwanted resistance. This unwanted resistance can change the way a circuit works.
• Electronically controlled circuits are very sens itive to proper grounding. A loose or corroded ground can
drastically affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit.
Even when the ground connection looks clean, there c an be a thin film of rust on the surface.
SGI847-A
Revision: March 2010 2008 QX56

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-43
< BASIC INSPECTION >
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• When inspecting a ground connection follow these rules:
- Remove the ground bolt or screw.
- Inspect all mating surfaces for tarnish, dirt, rust, etc.
- Clean as required to assure good contact.
- Reinstall bolt or screw securely.
- Inspect for “add-on” accessories which may be interfering with the ground circuit.
- If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of the wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eye-
let make sure no ground wires have excess wire insulation.
• For detailed ground distribution information, refer to “Ground Distribution” in PG section.
VOLTAGE DROP TESTS
• Voltage drop tests are often used to find components or circuits which have excessive resistance. A voltage drop in a circuit is caused by a resistance when the circuit is in operation.
• Check the wire in the illustration. When measuring re sistance with DMM, contact by a single strand of wire
will give reading of 0 ohms. This would indicate a good circuit. When the circuit operates, this single strand
of wire is not able to carry the current. The single strand will have a high resistance to the current. This will
be picked up as a slight voltage drop.
• Unwanted resistance can be caused by many situations as follows:
- Undersized wiring (single strand example)
- Corrosion on switch contacts
- Loose wire connections or splices.
• If repairs are needed always use wire that is of the same or larger gauge.
Measuring Voltage Drop — Accumulated Method
• Connect the DMM across the connector or part of the ci rcuit you want to check. The positive lead of the
DMM should be closer to power and the negative lead closer to ground.
• Operate the circuit.
• The DMM will indicate how many volts are being used to “push” current through that part of the circuit.
SGI853
Revision: March 2010 2008 QX56

GI-44
< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Note in the illustration that there is an excessive 4.1 volt drop between the battery and the bulb.
Measuring Voltage Drop — Steb-by-Step
• The step-by-step method is most useful for isolating excessive drops in low voltage systems (such as those
in “Computer Controlled Systems”).
• Circuits in the “Computer Controlled System” operate on very low amperage.
• The (Computer Controlled) system oper ations can be adversely affected by any variation in resistance in the
system. Such resistance variation may be caused by poor connection, improper installation, improper wire
gauge or corrosion.
• The step by step voltage drop test can identify a component or wire with too much resistance.
CONTROL UNIT CIRCUIT TEST
System Description
• When the switch is ON, the control unit lights up the lamp.
CASE 1
SGI974
SAIA0258E
MGI034A
Revision: March 2010 2008 QX56

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-45
< BASIC INSPECTION >
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INPUT-OUTPUT VOLTAGE CHART
• The voltage value is based on the body ground.
• *: If high resistance exists in the switch side circuit (caused by a single strand), terminal 1 does not detect battery voltag e. Control unit
does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not supply power to ligh t up the
lamp.
CASE 2
INPUT-OUTPUT VOLTAGE CHART
• The voltage value is based on the body ground.
• *: If high resistance exists in the switch side circuit (caused by a single strand), terminal 2 does not detect approx. 0V. Co ntrol unit
does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not control ground to li ght up the
lamp. Terminal No. Description
Condition Value (Approx.)In case of high resistance such as single
strand (V) *
+ −Signal name Input/
Output
1 Body
ground Switch Input Switch ON
Battery voltageLower than battery voltage Approx. 8 (Ex-
ample)
Switch OFF 0 V Approx. 0
2 Body
ground Lamp Output Switch ON
Battery voltage App rox. 0 (Inoperative lamp)
Switch OFF 0 V Approx. 0
Terminal No. Description
Condition Value (Approx.)In case of high resistance such as single
strand (V) *
+ −Signal name Input/
Output
1 Body
ground Lamp Output Switch ON
0VBattery voltage (Inoperative lamp)
Switch OFF Battery voltage Battery voltage
2 Body
ground Switch Input Switch ON
0 V Higher than 0 Approx. 4 (Example)
Switch OFF 5 V Approx. 5
MGI035A
Revision: March 2010 2008 QX56

GW-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004884108
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:0000000004881261
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

REAR WINDOW GLASS AND MOLDINGGW-7
< ON-VEHICLE REPAIR >
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REAR WINDOW GLASS AND MOLDING
Removal and InstallationINFOID:0000000001608354
REMOVAL
1. Remove the rear spoiler. Refer to EXT-26, "Removal and Installation".
2. Disconnect the rear window def ogger electrical connectors.
3. Remove the rear glass stays.
4. Remove the hinge nuts and the rear glass assembly.
5. Remove the striker and handle.
6. Remove the rear glass hinges.
1. Back door assembly 2. Weatherstrip3. Rear glass stay RH, LH
4. Rear window hinge assembly RH, LH 5. Rear window glass handle
6. Rear window glass latch striker
7. Rear glass assembly : Medium strength Thread Locking
Sealant (Blue)
AWKIA1526GB
Revision: March 2010 2008 QX56

HA-1
VENTILATION, HEATER & AIR CONDITIONER
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CONTENTS
HEATER & AIR CONDITIONING SYSTEM
PRECAUTION ....... ........................................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ............................... ......
3
Precaution for Working with HFC-134a (R-134a) ......4
Precaution for Procedure without Cowl Top Cover ......4
Contaminated Refrigerant .........................................4
General Refrigerant Precaution ................................5
Precaution for Leak Detection Dye ...........................5
A/C Identification Label .............................................5
Precaution for Refrigerant Connection ......................5
Precaution for Service of Compressor ................ ....10
Precaution for Service Equipment ....................... ....10
PREPARATION ...........................................13
PREPARATION .............................................. ....13
Special Service Tool ........................................... ....13
HFC-134a (R-134a) Service Tool and Equipment ....13
Commercial Service Tool ........................................16
FUNCTION DIAGNOSIS ..............................17
REFRIGERATION SYSTEM .......................... ....17
Refrigerant Cycle ................................................ ....17
Refrigerant System Protection ................................17
OIL .................................................................. ....19
Maintenance of Oil in Compressor ...................... ....19
ON-VEHICLE MAINTENANCE ....................20
REFRIGERATION SYSTEM .......................... ....20
HFC-134a (R-134a) Service Procedure ..................20
OIL .................................................................. ....22
Maintenance of Oil Quantity in Compressor ....... ....22
FLUORESCENT LEAK DETECTOR ................24
Checking of Refrigerant Leaks ................................24
Checking System for Leaks Using the Fluorescent
Dye Leak Detector ............................................... ....
24
Dye Injection ............................................................24
ELECTRICAL LEAK DETECTOR ....................26
Checking of Refrigerant Leaks ................................26
Electronic Refrigerant Leak Detector ................... ....26
ON-VEHICLE REPAIR .................................29
REFRIGERATION SYSTEM .............................29
Component .......................................................... ....29
COMPRESSOR .................................................31
Removal and Installation for Compressor ...............31
Removal and Installation for Compressor Clutch ....32
LOW-PRESSURE FLEXIBLE HOSE ................36
Removal and Installation for Low-Pressure Flexi-
ble Hose .............................................................. ....
36
LOW-PRESSURE PIPE ....................................37
Removal and Installation for Low-Pressure Pipe .....37
Removal and Installation for Rear High- and Low-
Pressure A/C and Heater Core Pipes ......................
37
Removal and Installation for Underfloor Rear
High- and Low-Pressure A/C and Heater Core
Pipes ........................................................................
38
HIGH-PRESSURE FLEXIBLE HOSE ...............40
Removal and Installation for High-Pressure Flexi-
ble Hose ..................................................................
40
HIGH-PRESSURE PIPE ....................................41
Removal and Installation for High-Pressure Pipe ....41
Removal and Installation for Rear High- and Low-
Pressure A/C and Heater Core Pipes .................. ....
41
Removal and Installation for Underfloor Rear
High- and Low-Pressure A/C and Heater Core
Pipes ........................................................................
43
Revision: March 2010 2008 QX56