Nissan Qashqai (2007-2010). Manual - part 10

SERVICE INFORMATION FOR ELECTRICAL INCIDENT

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< BASIC INSPECTION >

• 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.

Intermittent Incident

INFOID:0000000001095982

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-
lowing section illustrates ways to simulate the conditions/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

SAIA0255E

SEF348N

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< BASIC INSPECTION >

SERVICE INFORMATION FOR ELECTRICAL INCIDENT

Determine which connectors and wiring harness would affect the electrical system you are inspecting. Gently
shake each connector and harness while monitoring the system 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 corrosion. 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 verifying 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 previously 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

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 seating 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

SGI839

SGI842

SERVICE INFORMATION FOR ELECTRICAL INCIDENT

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< BASIC INSPECTION >

• The customer may indicate the incident goes away after the car

warms 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.

Circuit Inspection

INFOID:0000000001095983

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 testing electrical components. Gently shake the wiring

harness or electrical component to do this.

SGI843

SGI844

SGI845

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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SERVICE INFORMATION FOR ELECTRICAL INCIDENT

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 circuit. 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 circuits, 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, the 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 circuit, 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 methodically 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.
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

SGI846-A

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