NISSAN PRIMERA 1999 Electronic Repair Manual

Tester probe
When probing a connector it is possible to enlarge the contact
spring opening. If this occurs it may create an intermittent signal
in the circuit. When probing a connector, use care not to enlarge
the opening. The probe of the Digital Multimeter (DMM) may not
fit into the connector cavity. In such cases make an extension of
a ªTº pin and probe it from the harness side of the connector.
Most DMMs have accessory alligator clips. Slide these over the
probe to allow clipping the ªTº pin for a better contact. If you have
any difficulty probing a terminal, inspect the terminal. Ensure you
have not accidentally opened the contact spring or pulled a wire
loose.
SGI840
Possible causeAny probe entering the
terminal may enlarge
the contact spring
opening creating an
intermittent signal.
Enlarged
NormalProper crimp
Insulation not
removedIntermittent
signals
through
pierced
insulation
Wire strands
missing
DEFORMED (ENLARGED) FEMALE TERMINALS
DEFECTIVE INSULATION STRIPPING
Male half
Female half
Seal
Seal
Unlocked terminal
(Hidden by wire seal)Intermittent
contactCheck for unlocked terminals by
pulling each wire at the end of
the connector.
TERMINAL NOT PROPERLY SEATED Locked terminal
Loose
SGI841 Connector
ªTº pinAlligator clip
DMM
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests (Cont'd)
GI-26

Engine compartment
There are several reasons a vehicle or engine vibration could
cause an electrical complaint. Some of the things to check for
are:
lConnectors not fully seated.
lWiring harness not long enough and is being stressed due
to engine vibrations or rocking.
lWires laying across brackets or moving components.
lLoose, dirty or corroded ground wires.
lWires routed too close to hot components.
To inspect components under the hood, start by verifying the
integrity of ground connections. (Refer to GROUND INSPEC-
TION described later.) First check that the system is properly
grounded. Then check for loose connection bygently 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. Vehicle 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 vibra-
tion. If the wiring runs under seating areas, inspect wire routing
for possible damage or pinching.
HEAT SENSITIVE
The owner's problem 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.
Do not heat components above 60ÉC (140ÉF).If incident
occurs while heating the unit, either replace or properly insulate
the component.
SGI842 Heating test
Heat gun
Do not heat above 60ÉC (140ÉF).
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests (Cont'd)
GI-27

FREEZING
The customer may indicate the incident goes away after the car
warms up (winter time). The cause could be related to water
freezing 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 diagno-
sis 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 intrusion on an electrical part. This can be simulated by
soaking the car or running it through a car wash.
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.
SGI843 Freezing test
Water in
connector
SolenoidShort
SGI844
Water intrusion test
SGI845 Electrical load test
ªONº
Rear win-
dow defog-
gerLight switch A/C
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests (Cont'd)
GI-28

Circuit Inspection
INTRODUCTION
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
thorough 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 shakethe wiring
harness or electrical component to do this.
OPEN A circuit is open when there is no continuity through a section of the circuit.
SHORT There are two types of shorts.
lSHORT CIRCUITWhen a circuit contacts another circuit and causes the
normal resistance to change.
lSHORT TO GROUNDWhen a circuit contacts a ground source and grounds the
circuit.
TESTING FOR ªOPENSº 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
working 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 resis-
tance function will indicate an open circuit as over limit (OL, 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 schematic above.
1. Disconnect the battery negative cable.
2. Start at one end of the circuit and work your way to the other end. (At the fuse block in this example)
3. Connect one probe of the DMM to the fuse block terminal on the load side.
4. Connect the other probe to the fuse block (power) side of SW1. 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 resistance condition. (point A)
5. 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 resistance condition. (point B)
6. 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 infinite resistance condition. (point C)
Any circuit can be diagnosed using the approach in the above example.
SGI846
Inspection for opens
FUSE BLOCK
B+ SIDEDMM(Voltage check)
SW1N.C. RELAY
SOLENOID
OPEN
AOPEN
BOPEN
C
DMMDMM
SW2
(Continuity check)
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
GI-29

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 volt-
age. This is done by switching the DMM to the voltage function.
1. Connect one probe of the DMM to a known good ground.
2. Begin probing at one end of the circuit and work your way to the other end.
3. 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).
4. 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).
5. 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 above example.
TESTING FOR ªSHORTSº IN THE CIRCUIT
To simplify the discussion of shorts in the system please refer to the schematic below.
Resistance check method
1. Disconnect the battery negative cable and remove the blown fuse.
2. Disconnect all loads (SW1 open, relay disconnected and solenoid disconnected) powered through the
fuse.
3. Connect one probe of the ohmmeter to the load side of the fuse terminal. Connect the other probe to a
known good ground.
4. 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.
5. 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.
6. 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.
SGI847
Inspection for shorts
IGN ªONº
OR ªSTARTº
B+ SIDEFUSE BLOCKDMM(Resistance check)
SW1RELAY
SOLENOID
SHORT
ASHORT
BSHORT
C
DMM
(Voltage check)SW2
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-30

Voltage check method
1. Remove the blown fuse and disconnect all loads (i.e. SW1 open, relay disconnected and solenoid dis-
connected) powered through the fuse.
2. Turn the ignition key to the ON or START position. Verify battery voltage at the B
+side of the fuse ter-
minal (one lead on the B
+terminal side of the fuse block and one lead on a known good ground).
3. 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.
4. 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.
5. 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 sensitive 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 can be a thin film of rust on the surface.
When inspecting a ground connection follow these rules:
1. Remove the ground bolt screw or clip.
2. Inspect all mating surfaces for tarnish, dirt, rust, etc.
3. Clean as required to assure good contact.
4. Reinstall bolt or screw securely.
5. Inspect for ªadd-onº accessories which may be interfering with the ground circuit.
6. 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 eyelet make sure no ground wires have excess wire insulation.
SGI853
Ground Inspection
Remove bolt (screw). Inspect mating surfaces
for tarnish, dirt, rust, etc.
Clean as required to
assure good contact.Reinstall bolt (screw)
securely.
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-31

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 resistancewhen the circuit is in operation.
Check the wire in the illustration. When measuring resistance with ohmmeter, 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 Ð Accumulated method
1. Connect the voltmeter across the connector or part of the circuit you want to check. The positive lead
of the voltmeter should be closer to power and the negative lead closer to ground.
2. Operate the circuit.
3. The voltmeter will indicate how many volts are being used to ªpushº current through that part of the cir-
cuit.
Note in the illustration that there is an excessive 4.1 volt drop between the battery and the bulb.
Measuring voltage drop Ð Step by step
The step by step method is most useful for isolating excessive drops in low voltage systems (such as those
in ªComputer Controlled Systemsº).
Circuits in the ªComputer Controlled Systemº operate on very low amperage.
The (Computer Controlled) system operations 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.
SGI848
Symptom: Dim bulb or no operation
0 (zero) ohm
resistance
between switch
and bulb
GroundBatteryDMM
PowerSwitchLoad
Connection with
high resistance
Ground
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-32

SGI854 1. Connect the voltmeter as shown, starting at the battery and
working your way around the circuit.
2. An unusually large voltage drop will indicate a component or
wire that needs to be repaired. The illustration shows a poor
connection causes a 4 volt drop.
The chart that follows illustrates some maximum allowable voltage drops. These values are given as a guideline, the exact value for each component
may vary.
COMPONENT
Wire
Ground Connections
Switch ContactsVOLTAGE DROP
Negligible <.001 volts
Approx. 0.1 volts
Approx. 0.3 volts BatterySwitch
Connection
with high
resistance
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-33

Relationship between open/short (high resistance) circuit and the ECM pin control
System Description: When the switch is ON, the ECM lights up the lamp.
SGI849-A
Case 1
BatteryFUSESwitchTERMINAL: 1
Monitoring
of the switch
operation (ON/OFF)TERMINAL: 2
Power supply
to light up
the lampLamp
Short: FUSE blows.
Open: Inoperative lampShort: FUSE blows
when switch is ON.
Open: Inoperative lamp
High resistance:
(Single strand) See below.*ECM
Short & Open:
Inoperative lampShort: No problem
Open: Inoperative lamp
Case 2
BatteryFUSELampTERMINAL: 1
Ground control
to light up the lampTERMINAL: 2
Monitoring
of the switch
operation (ON/OFF)Switch
Short: FUSE blows.
Open: Inoperative lampShort: Lamp stays ON.
Open: Inoperative lampShort: Lamp stays ON.
(Same as the switch ON)
Open: Inoperative lamp
High resistance: See below.
(Single strand)*Short: No problem
Open: Inoperative lamp ECM
Pin
No.Item Condition Voltage
value [V]In case of high resistance such
as single strand [V] *
1 Switch Switch Battery Lower than battery voltage
ON voltage Approx. 8 (Example)
OFF Approx. 0 Approx. 0
2 Lamp Switch Battery Approx. 0
ON voltage (Inoperative lamp)
OFF Approx. 0 Approx. 0
The voltage value is based on the body ground.
Input-output voltage chart
Pin
No.Item Condition Voltage
value [V]In case of high resistance
such as single strand [V] *
1 Lamp Switch Approx. 0 Battery voltage
ON (Inoperative lamp)
OFF Battery
voltageBattery voltage
2 Switch Switch Approx. 0 Higher than 0
ON Approx. 4 (Example)
OFF Approx. 5 Approx. 5
The voltage value is based on the body ground.
Input-output voltage chart
* : If high resistance exists in the switch side circuit (caused by a single strand), terminal 1 does not detect battery voltage. ECM does not detect the
switch is ON even if the switch does turn ON. Therefore, the ECM does not supply power to light up the lamp.
* : If high resistance exists in the switch side circuit (caused by a single strand), terminal 2 does not detect approx. 0V. ECM does not detect the switch
is ON even if the switch does turn ON. Therefore, the ECM does not control ground to light up the lamp.
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-34

NOTICE
Trouble diagnoses indicates work procedures required to diag-
nose problems effectively. Observe the following instructions
before diagnosing.
1) Before performing trouble diagnoses, read the ªPrelimi-
nary Checkº, the ªSymptom Chartº or the ªWork Flowº.
2) After repairs, re-check that the problem has been com-
pletely eliminated.
3) Refer to Component Parts and Harness Connector Loca-
tion for the Systems described in each section for
identification/location of components and harness con-
nectors.
4) Refer to the Circuit Diagram for Quick Pinpoint Check.
If you need to check circuit continuity between harness
connectors in more detail, such as when a sub-harness
is used, refer to Wiring Diagram in each individual sec-
tion and Harness Layout in EL section for identification
of harness connectors.
5) When checking circuit continuity, ignition switch should
be in the ªLOCKº position.
6) Before checking voltage at connectors, check battery
voltage.
7) After accomplishing the Diagnostic Procedures and
Electrical Components Inspection, make sure that all
harness connectors are reconnected as they were.
How to Follow Test Groups in Trouble
Diagnoses
Example Type A
SGI800-C
INSPECTION START
CHECK POWER SUPPLY.
1) Turn ignition switch to ªONº posi-
tion.
2) Check voltage between terminal
pband ground.
Battery voltage should exist
OK
ENG
Check the following
items.
1) Harness continuity
between camshaft
position sensor and
battery
2) Engine relay-1
3) ªBRº fusible link
4) Power source for
ECM
5) Ignition switch
CHECK GROUND CIRCUIT.
1) Turn ignition switch to ªOFFº posi-
tion.
2) Disconnect camshaft position sen-
sor harness connector.
3) Check resistance between termi-
nal
pdand ground.
Resistance:
Approximately 0W
OK
ENG
Check the following
items.
1) Harness continuity
between camshaft
position sensor and
ground
2) Ground circuit for
ECM
H
H
H
HOW TO FOLLOW TROUBLE DIAGNOSES
GI-35