Electrical NISSAN PATROL 2006 Workshop Manual

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.
+SHORT CIRCUITWhen a circuit contacts another circuit and causes the
normal resistance to change.
+SHORT TO GROUNDWhen a circuit contacts a ground source and grounds the
circuit.
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 ®nd an open in the circuit. The Digital Multimeter (DMM) set on the resistance
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 in®nite resistance condition. (point A)
5. Connect the probes between SW1 and the relay. Little or no resistance will indicate that portion of the cir-
cuit has good continuity. If there were an open in the circuit, the DMM would indicate an over limit or in®-
nite 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 in®nite resistance condition. (point C)
Any circuit can be diagnosed using the approach in the above example.
SGI846
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
GI-24

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 ``SHORTS'' 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
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-25

Voltage check method
1. Remove the blown fuse and disconnect all loads (i.e. SW1 open, relay disconnected and solenoid discon-
nected) 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 dras-
tically 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 ®lm 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 ``add-on'' 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
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-26

VOLTAGE DROP TESTS
Voltage drop tests are often used to ®nd 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 ``push'' 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 ``Computer Controlled Systems'').
Circuits in the ``Computer Controlled System'' 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.
SGI974
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-27

SGI854
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-28

CONTROL UNIT CIRCUIT TEST
System Description: When the switch is ON, the control unit lights up the lamp.
AGI059
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-29

SAE J1930 Terminology List
All emission related terms used in this publication in accordance with SAE J1930 are listed. Accordingly, new
terms, new acronyms/abbreviations and old terms are listed in the following chart.
***: Not applicable
NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Air cleaner ACL Air cleaner
Barometric pressure BARO ***
Barometric pressure sensor-BCDD BAROS-BCDD BCDD
Camshaft position CMP ***
Camshaft position sensor CMPS Crank angle sensor
Canister *** Canister
Carburetor CARB Carburetor
Charge air cooler CAC Intercooler
Closed loop CL Closed loop
Closed throttle position switch CTP switch Idle switch
Clutch pedal position switch CPP switch Clutch switch
Continuous fuel injection system CFI system ***
Continuous trap oxidizer system CTOX system ***
Crankshaft position CKP ***
Crankshaft position sensor CKPS ***
Data link connector DLC ***
Data link connector for CONSULT DLC for CONSULT Diagnostic connector for CONSULT
Diagnostic test mode DTM Diagnostic mode
Diagnostic test mode selector DTM selector Diagnostic mode selector
Diagnostic test mode I DTM I Mode I
Diagnostic test mode II DTM II Mode II
Diagnostic trouble code DTC Malfunction code
Direct fuel injection system DFI system ***
Distributor ignition system DI system Ignition timing control
Early fuel evaporation-mixture heater EFE-mixture heater Mixture heater
Early fuel evaporation system EFE system Mixture heater control
Electrically erasable programmable read only
memoryEEPROM ***
Electronic ignition system EI system Ignition timing control
Engine control EC ***
Engine control module ECM ECCS control unit
Engine coolant temperature ECT Engine temperature
Engine coolant temperature sensor ECTS Engine temperature sensor
Engine modi®cation EM ***
Engine speed RPM Engine speed
Erasable programmable read only memory EPROM ***
Evaporative emission canister EVAP canister Canister
SAE J1930 TERMINOLOGY LIST
GI-43

***: Not applicable
NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Evaporative emission system EVAP system Evaporative emission control system
Exhaust gas recirculation valve EGR valve EGR valve
Exhaust gas recirculation control-BPT valve EGRC-BPT valve BPT valve
Exhaust gas recirculation control-solenoid valve EGRC-solenoid valve EGR control solenoid valve
Exhaust gas recirculation temperature sensor
EGRT sensor Exhaust gas temperature sensor
EGR temperature sensor
Flash electrically erasable programmable read
only memoryFEEPROM ***
Flash erasable programmable read only memory FEPROM ***
Flexible fuel sensor FFS ***
Flexible fuel system FF system ***
Fuel pressure regulator *** Pressure regulator
Fuel pressure regulator control solenoid valve *** PRVR control solenoid valve
Fuel trim FT ***
Heated Oxygen sensor HO2S Exhaust gas sensor
Idle air control system IAC system Idle speed control
Idle air control valve-air regulator IACV-air regulator Air regulator
Idle air control valve-auxiliary air control valve IACV-AAC valve Auxiliary air control (AAC) valve
Idle air control valve-FICD solenoid valve IACV-FICD solenoid valve FICD solenoid valve
Idle air control valve-idle up control solenoid
valveIACV-idle up control solenoid
valveIdle up control solenoid valve
Idle speed control-FI pot ISC-FI pot FI pot
Idle speed control system ISC system ***
Ignition control IC ***
Ignition control module ICM ***
Indirect fuel injection system IFI system ***
Intake air IA Air
Intake air temperature sensor IAT sensor Air temperature sensor
Knock *** Detonation
Knock sensor KS Detonation sensor
Malfunction indicator lamp MIL Check engine light
Manifold absolute pressure MAP ***
Manifold absolute pressure sensor MAPS ***
Manifold differential pressure MDP ***
Manifold differential pressure sensor MDPS ***
SAE J1930 TERMINOLOGY LIST
SAE J1930 Terminology List (Cont'd)
GI-44

MANUAL AND AUTO
SERVICE PROCEDURES........................................... 112
HFC-134a (R-134a) Service Procedure .................. 112
Maintenance of Lubricant Quantity in
Compressor ............................................................. 114
Ventilation Air Filter .................................................. 116
Refrigerant Lines ..................................................... 117Checking Refrigerant Leaks .................................... 119
Compressor Mounting .............................................122
Compressor Ð DKS-17CH......................................123
Compressor Clutch ..................................................123
SERVICE DATA AND SPECIFICATIONS...................126
General Speci®cations .............................................126
Inspection and Adjustment ......................................126
When you read wiring diagrams:
+Read GI section, ``HOW TO READ WIRING DIAGRAMS''.
+See EL section, ``POWER SUPPLY ROUTING'' for power distribution circuit.
When you perform trouble diagnoses, read GI section, ``HOW TO FOLLOW FLOW
CHART IN TROUBLE DIAGNOSES'' and ``HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT''.

Supplemental Restraint System (SRS) ``AIR
BAG'' and ``SEAT BELT PRE-TENSIONER''
The Supplemental Restraint System such as ``AIR BAG'' and ``SEAT BELT PRE-TENSIONER'' used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger in a frontal collision.
The SRS system composition which is available to NISSAN MODEL Y61 is as follows (The composition var-
ies according to the destination.):
Driver air bag module (located in the center of the steering wheel), front passenger air bag module (located
on the instrument panel on passenger side), seat belt pre-tensioner, a diagnosis sensor unit, warning lamp,
wiring harness and spiral cable.
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
+To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag in¯ation, all maintenance must be performed
by an authorized NISSAN dealer.
+Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
+Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation either just before
the harness connectors or for the complete harness are related to the SRS.
Precautions for Working with HFC-134a
(R-134a)
WARNING:
+CFC-12 (R-12) refrigerant and HFC-134a (R-134a) refrigerant are not compatible. These refriger-
ants must never be mixed, even in the smallest amounts. If the refrigerants are mixed, compres-
sor failure is likely to occur.
+Use only speci®ed lubricant for the HFC-134a (R-134a) A/C system and HFC-134a (R-134a) com-
ponents. If lubricant other than that speci®ed is used, compressor failure is likely to occur.
+The speci®ed HFC-134a (R-134a) lubricant rapidly absorbs moisture from the atmosphere. The
following handling precautions must be observed:
a: When removing refrigerant components from a vehicle, immediately cap (seal) the component
to minimize the entry of moisture from the atmosphere.
b: When installing refrigerant components to a vehicle, do not remove the caps (unseal) until
just before connecting the components. Connect all refrigerant loop components as quickly
as possible to minimize the entry of moisture into system.
c: Only use the speci®ed lubricant from a sealed container. Immediately reseal containers of
lubricant. Without proper sealing, lubricant will become moisture saturated and should not
be used.
d: Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose
and throat. Use only approved recovery/recycling equipment to discharge HFC-134a (R-134a)
refrigerant. If accidental system discharge occurs, ventilate work area before resuming ser-
vice. Additional health and safety information may be obtained from refrigerant and lubricant
manufacturers.
e: Do not allow lubricant (Nissan A/C System Oil Type S) to come in contact with styrofoam
parts. Damage may result.
PRECAUTIONS AND PREPARATIONMANUAL AND AUTO
HA-1