service INFINITI QX56 2011 Factory Service Manual

SERVICE INFORMATION FOR ELECTRICAL INCIDENTGI-39
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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:
Never 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:
Never 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, check 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:0000000006280854
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. Doing 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 syst em 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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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:
Never heat components above 60 °C (140 °F).
 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. Check it will get cold enough
to demonstrate his complaint. Leave the car parked outside over-
night. 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:
Never 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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Circuit InspectionINFOID:0000000006280855
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-37, "
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). Check 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 circui ts 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.
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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 sy stem, 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 continuit: 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 wir e. 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 switch to the ON or START position. Verify battery voltage at the battery + side of the fuse
terminal (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.
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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. Check all of the wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eyelet
check no ground wires have excess wire insulation.
 For detailed ground distribution information, re fer 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 st rand 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.
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Note in the illustration that there is an excessive 4.1 volt drop between the battery and the bulb.
Measuring Voltage Drop — Step-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
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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. 0 V. C ontrol 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 voltage
Lower 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 0 V Battery 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
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INSPECTION AND ADJUSTMENTGI-65
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ADDITIONAL SERVICE WHEN REMOVING BATTERY NEGATIVE TERMINAL
ADDITIONAL SERVICE WHEN REMOVING BATTERY NEGATIVE TERMINAL : Re-
quired Procedure After Battery Disconnection
INFOID:0000000006344676
*: Not equipped. SYSTEM ITEM REFERENCE
Front automatic air
conditioning system Temperature setting trimmer (Front)
HAC-68, "
FRONT AUTOMATIC
AIR CONDITIONING SYSTEM :
Temperature Setting Trimmer
(Front)"
Foot position setting trimmer
HAC-68, "
FRONT AUTOMATIC
AIR CONDITIONING SYSTEM :
Foot Position Setting Trimmer"
Inlet port memory function* —
Inlet port memory function (FRE)
HAC-69, "
FRONT AUTOMATIC
AIR CONDITIONING SYSTEM :
Inlet Port Memory
Function (FRE)"
Inlet port memory function (REC) HAC-69, "
FRONT AUTOMATIC
AIR CONDITIONING SYSTEM :
Inlet Port Memory Function (REC)"
ACCS (Advanced Cli-
mate Control System)Exhaust gas / outside odor detecting sensor sensitivity adjustment func-
tion
HAC-70, "
ACCS (ADVANCED
CLIMATE CONTROL SYSTEM) :
Exhaust Gas / Outside Odor De-
tecting Sensor Sensitivity Adjust-
ment Function"
Auto intake switch interlocking movement change function
HAC-70, "
ACCS (ADVANCED
CLIMATE CONTROL SYSTEM) :
Auto Intake Switch Interlocking
Movement Change Function"
Clean switch interlocking movement change function* —
Rear automatic air
conditioning system Temperature setting trimmer (Rear) HAC-69, "
REAR AUTOMATIC AIR
CONDITIONING SYSTEM : Tem-
perature Setting
Trimmer (Rear)"
Automatic drive posi-
tioner Automatic drive positioner system ADP-51, "
ADDITIONAL SERVICE
WHEN REMOVING BATTERY
NEGATIVE TERMINAL : Descrip-
tion"
Power window control Power window control system
PWC-31, "Description"
Sunroof system* Sunroof system —
Sunshade system* Sunshade system —
Rear view monitor* Rear view monitor predictive course line center position adjustment —
Around view monitor Predictive course line center position adjustment AV- 111 , "
Description"
Automatic back door
systemAutomatic back door system DLK-80, "
ADDITIONAL SERVICE
WHEN REMOVING BATTERY
NEGATIVE TERMINAL : Descrip-
tion"
Engine oil level read* Engine oil level read —
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