2008 INFINITI QX56 Electrical

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< PRECAUTION >
PRECAUTIONS
• Before starting repairs which do not require battery power:Turn off ignition switch.
Disconnect the negative battery terminal.
• If the battery terminals are disconnected, recorded memory of radio and each control unit is erased.
• To prevent serious burns: Avoid contact with hot metal parts.
Do not remove the radiator cap when the engine is hot.
• Dispose of drained oil or the solvent used for cleaning parts in an appropriate manner.
• Do not attempt to top off the fuel tank after the fuel pump nozzle
shuts off automatically.
Continued refueling may cause fuel overflow, resulting in fuel spray
and possibly a fire.
• Clean all disassembled parts in the designated liquid or solvent prior to inspection or assembly.
• Replace oil seals, gaskets, packings, O-rings, locking washers,
cotter pins, self-locking nuts, etc. with new ones.
• Replace inner and outer races of tapered roller bearings and needle bearings as a set.
• Arrange the disassembled parts in accordance with their assembled locations and sequence.
• Do not touch the terminals of electrical com ponents which use microcomputers (such as ECM).
Static electricity may damage internal electronic components.
• After disconnecting vacuum or air hoses, atta ch a tag to indicate the proper connection.
• Use only the fluids and lubricants specified in this manual.
• Use approved bonding agent, sealants or their equivalents when required.
• Use hand tools, power tools (disassembly only) and recommended special tools where specified for safe and efficient service repairs.
• When repairing the fuel, oil, water, vacuum or exhaust systems, check all affected lines for leaks.
• Before servicing the vehicle: Protect fenders, upholstery and carpeting with appropriate covers.
Take caution that keys, buckles or buttons do not scratch paint.
WARNING:
To prevent ECM from storing the diagnostic tro uble codes, do not carelessly disconnect the harness
connectors which are related to the engine control system and TCM (transmission control module)
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SERVICE INFORMATION FOR ELECTRICAL INCIDENT
BASIC INSPECTION
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Work FlowINFOID:0000000001539223
WORK FLOW
Control Units and Electrical PartsINFOID:0000000001539224
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.
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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 to prevent condensation in the control unit due to rapid
temperature changes and do not let water or rain get on it. If water
is found in the control unit, dry it fully and then install it in the vehi-
cle.
• Be careful not to let oil to get on the control unit connector.
• Avoid cleaning the control unit with volatile oil.
• Do not disassemble the control unit, and do not remove the upper and lower covers.
• When using a DMM, be careful not to let test probes get close to each other to prevent the power transistor in the control unit from
damaging battery voltage because of short circuiting.
• When checking input and output signals of the control unit, use the specified check adapter.
How to Check TerminalINFOID:0000000001539225
CONNECTOR AND TERMINAL PIN KIT
• Use the connector and terminal pin kits listed below when replacing connectors or terminals.
• The connector and terminal pin kits contain some of the most commonly used NISSAN/INFINITI connectors
and terminals. For detailed connector and terminal pin r eplacement procedures, refer to the latest NISSAN/
INFINITI CONNECTOR AND TERMINAL PIN SERVICE MANUAL.
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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 dur-ing circuit checks.
• The probe of a digital multimeter (DMM) may not correctly fit the connector cavity. To correctly probe the connector, follow the procedures below using a “T” pin. For the best contact grasp the “T” pin using an alliga-
tor clip.
Probing from Harness Side
Standard type (not waterproof type) connector should be probed
from harness side with “T” pin.
• If the connector has a rear cover such as a ECM connector,remove the rear cover before probing the terminal.
• Do not probe waterproof connector from harness side. Damage to the seal between wire and connector may result.
Probing from Terminal Side
FEMALE TERMINAL
• There is a small notch above each female terminal. Probe each
terminal with the “T” pin through the notch.
Do not insert any object other than the same type male terminal
into female terminal.
Tool number
(Kent-Moore No.) Tool name Description
-
(J38751-95NI)
Connector and terminal
pin kit (NISSAN)
-
(J38751-95INF)
Connector and terminal
pin kit (INFINITI)
-
(J42992-98KIT)
OBD and terminal repair
kit
-
(J42992-2000UPD)
OBD-II Connector Kit Up-
date
WAIA0004EWAIA0005E
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• Some connectors do not have a notch above each terminal. To probe each terminal, remove the connector retainer to make con-
tact space for probing.
MALE TERMINAL• Carefully probe the contact surface of each terminal using a “T”pin.
CAUTION:
Dot not bend terminal.
How to Check Enlarged Cont act Spring of Terminal
• An enlarged contact spring of a terminal may create intermittent signals in the circuit.
• If the intermittent open circuit occurs, follow the pr ocedure below to inspect for open wires and enlarged con-
tact spring of female terminal.
1. Assemble a male terminal and approx. 10 cm (3.9 in) of wire. NOTE:
Use a male terminal which matches the female terminal.
2. Disconnect the suspected faulty connector and hold it terminal side up.
3. While holding the wire of the male terminal, try to insert the male terminal into the female terminal.
CAUTION:
Do not force the male terminal into the female terminal with
your hands.
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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 easily inserted into the female ter-minal, replace the female terminal.
Waterproof Connector Inspection
If water enters the connector, it can short interior circuits. This may lead to intermittent problems.
Check the following items to maintain the original waterproof characteristics.
RUBBER SEAL INSPECTION• Most waterproof connectors are provided with a rubber seal between the male and female connectors. If the seal is missing,
the waterproof performance may not meet specifications.
• The rubber seal may come off when connectors are disconnected.
Whenever connectors are reconnected, make sure the rubber seal
is properly installed on either side of male or female connector.
WIRE SEAL INSPECTION• The wire seal must be installed on the wire insertion area of awaterproof connector. Be sure that the seal is installed properly.
Terminal Lock Inspection
Check for unlocked terminals by pulling wire at the end of connector.
An unlocked terminal may create intermittent signals in the circuit.
Intermittent IncidentINFOID:0000000001539226
DESCRIPTION
Sometimes the symptom is not present when the vehicle is brought in for service. If possible, re-create the
conditions present at the time of the incident. Doi ng so may help avoid a No Trouble Found Diagnosis. The fol-
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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
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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. 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.
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