2010 INFINITI QX56 Factory Service Manual

oil capacity change time maintenance engine park assist spare wheel

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INFINITI QX56 2010 Factory Service Manual GI-34
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SERVICE INFORMATION FOR ELECTRICAL INCIDENT
BASIC INSPECTION
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Work FlowINFOID:0000000005149604
WORK FLOW
Control Units and Electri

GI-34
< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
BASIC INSPECTION
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Work FlowINFOID:0000000005149604
WORK FLOW
Control Units and Electrical PartsINFOID:0000000005149605
PRECAUTIONS
• Never reverse polarity of battery terminals.
• Install only parts specified for a vehicle.
• Before replacing the control unit, check the i nput and output and functions of the component parts.
• Do not apply excessive force when disconnecting a connector.
SGI838
STEP DESCRIPTION
STEP 1 Get detailed information about the conditions and the environment when the incident occurred.
The following are key pieces of information required to make a good analysis:
WHAT
Vehicle Model, Engine, Transmission/Transaxle and the System (i.e. Radio).
WHEN Date, Time of Day, Weather Conditions, Frequency.
WHERE Road Conditions, Altitude and Traffic Situation.
HOW System Symptoms, Operating Conditions
(Other Components Interaction).
Service History and if any After Market Accessories have been installed.
STEP 2 Operate the system, road test if necessary.
Verify the parameter of the incident.
If the problem cannot be duplicated, refer to “Incident Simulation Tests”.
STEP 3 Get the proper diagnosis materials together including:
• Power Supply Routing
• System Operation Descriptions
• Applicable Service Manual Sections
• Check for any Service Bulletins
Identify where to begin diagnosis based upon your knowledge of the system operation and the customer comments.
STEP 4 Inspect the system for mechanical binding, loose connectors or wiring damage.
Determine which circuits and components are involved and diagnose using the Power Supply Routing and Harness Lay-
outs.
STEP 5 Repair or replace the incident circuit or component.
STEP 6 Operate the system in all modes. Verify the system works properly under all conditions. Make sure you have not inad-
vertently created a new incident during your diagnosis or repair steps.
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• Do not apply excessive shock to the control unit by dropping or hit- ting it.
• Be careful t

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INFINITI QX56 2010 Factory Service Manual GI-36
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SERVICE INFORMATION FOR ELECTRICAL INCIDENT
HOW TO PROBE CONNECTORS
• Connector damage and an intermittent connection can result from improperly probing of the connector d

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• Some connectors do not have a notch above each terminal. To probe each terminal, remove the co

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INFINITI QX56 2010 Factory Service Manual GI-38
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SERVICE INFORMATION FOR ELECTRICAL INCIDENT
4. While moving the connector, check whether the male terminalcan be easily inserted or not.
• If the male terminal can be easi

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lowing section illustrates ways to simulate the c onditions/environment under which the owner expe

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lowing section illustrates ways to simulate the c onditions/environment under which the owner experiences an
electrical incident.
The section is broken into the six following topics:• Vehicle vibration
• Heat sensitive
• Freezing
• Water intrusion
• Electrical load
• Cold or hot start up
Get a thorough description of the incident from the customer . It is important for simulating the conditions of the
problem.
VEHICLE VIBRATION
The problem may occur or become worse while driving on a rough road or when engine is vibrating (idle with
A/C on). In such a case, you will want to check for a vibration related condition. Refer to the following illustra-
tion.
Connector & Harness
Determine which connectors and wiring harness would affect the electrical system you are inspecting. Gently
shake each connector and harness while monitoring the syst em for the incident you are trying to duplicate.
This test may indicate a loose or poor electrical connection.
Hint
Connectors can be exposed to moisture. It is possible to get a thin film of corrosion on the connector termi-
nals. A visual inspection may not reveal this without disconnecting the connector. If the problem occurs inter-
mittently, perhaps the problem is caused by corrosi on. It is a good idea to disconnect, inspect and clean the
terminals on related connectors in the system.
Sensor & Relay
Gently apply a slight vibration to sensors and relays in the system you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
Engine Compartment
There are several reasons a vehicle or engine vibration could cause an electrical complaint. Some of the
things to check for are:
• Connectors not fully seated.
• Wiring harness not long enough and is being stressed due to engine vibrations or rocking.
• Wires laying across brackets or moving components.
• Loose, dirty or corroded ground wires.
• Wires routed too close to hot components.
To inspect components under the hood, start by verifyi ng the integrity of ground connections. (Refer to Ground
Inspection described later.) First check that the system is properly grounded. Then check for loose connection
by gently shaking the wiring or components as previous ly explained. Using the wiring diagrams inspect the
wiring for continuity.
Behind the Instrument Panel
An improperly routed or improperly clamped harness can become pinched during accessory installation. Vehi-
cle vibration can aggravate a harness which is routed along a bracket or near a screw.
Under Seating Areas
SGI839
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INFINITI QX56 2010 Factory Service Manual GI-40
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SERVICE INFORMATION FOR ELECTRICAL INCIDENT
An unclamped or loose harness can cause wiring to be pinched by seat components (such as slide guides)
during vehicle vibration.

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< BASIC INSPECTION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
An unclamped or loose harness can cause wiring to be pinched by seat components (such as slide guides)
during vehicle vibration. If the wiring runs under s eating areas, inspect wire routing for possible damage or
pinching.
HEAT SENSITIVE
• The customer's concern may occur during hot weather or after car has sat for a short time. In such cases you will want to check for a
heat sensitive condition.
• To determine if an electrical component is heat sensitive, heat the component with a heat gun or equivalent.
CAUTION:
Do not heat components above 60 °C (140° ).
• If incident occurs while heating the unit, either replace or properly insulate the component.
FREEZING
• The customer may indicate the incident goes away after the carwarms up (winter time). The cause could be related to water freez-
ing somewhere in the wiring/electrical system.
• There are two methods to check for this. The first is to arrange for the owner to leave his car overnight. Make sure it will get cold
enough to demonstrate his complaint. Leave the car parked out-
side overnight. In the morning, do a quick and thorough diagnosis
of those electrical components which could be affected.
• The second method is to put the suspect component into a freezer long enough for any water to freeze. Reinstall the part into the car
and check for the reoccurrence of the incident. If it occurs, repair or
replace the component.
WATER INTRUSION
The incident may occur only during high humidity or in rainy/snowy
weather. In such cases the incident could be caused by water intru-
sion on an electrical part. This can be simulated by soaking the car
or running it through a car wash.
CAUTION:
Do not spray water directly on any electrical components.
ELECTRICAL LOAD
The incident may be electrical load sensitive. Perform diagnosis with
all accessories (including A/C, rear window defogger, radio, fog
lamps) turned on.
COLD OR HOT START UP
On some occasions an electrical incident may occur only when the car is started cold, or it may occur when
the car is restarted hot shortly after being turned off. In these cases you may have to keep the car overnight to
make a proper diagnosis.
SGI842
SGI843
SGI844
SGI845
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Circuit InspectionINFOID:0000000005149608
DESCRIPTION
• In general, testing electrical circuits

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-41
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Circuit InspectionINFOID:0000000005149608
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: April 20092010 QX56

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