
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.
SGI844
WATER INTRUSIONNJGI0005S0205The 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.
SGI845
ELECTRICAL LOADNJGI0005S0206The incident may be electrical load sensitive. Perform diagnoses
with all accessories (including A/C, rear window defogger, radio,
fog lamps) turned on.
COLD OR HOT START UPNJGI0005S0207On 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 diagnoses.
Circuit InspectionNJGI0005S03INTRODUCTIONNJGI0005S0301In 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 com-
ponent 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 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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HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests (Cont’d)
GI-25

TESTING FOR “OPENS” IN THE CIRCUITNJGI0005S0302Before you begin to diagnose and test the system, you should
rough sketch a schematic of the system. This will help you to logi-
cally walk through the diagnoses process. Drawing the sketch will
also reinforce your working knowledge of the system.
SGI846
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 diagnoses 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 con-
tinuity. 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.
Voltage Check Method
To help in understanding the diagnoses 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.
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.
HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont’d)
GI-26

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 CIRCUITNJGI0005S0303To simplify the discussion of shorts in the system please refer to
the schematic below.
SGI847
Resistance Check Method
1) Disconnect the battery negative cable and remove the blown
fuse.
2) Disconnect all loads (SW1 open, relay disconnected and sole-
noid 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.
Voltage Check Method
1) Remove the blown fuse and disconnect all loads (i.e. SW1
open, relay disconnected and solenoid disconnected) powered
through the fuse.
2) Turn the ignition key to the ON or START position. Verify bat-
tery voltage at the B + side of the fuse terminal (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).
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HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont’d)
GI-27

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 — Accumulated Method
1) Connect the voltmeter across the connector or part of the cir-
cuit 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 circuit.
Note in the illustration that there is an excessive 4.1 volt drop
between the battery and the bulb.
SGI974
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 Con-
trolled 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 resis-
tance 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.
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HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont’d)
GI-29

SGI854
CONTROL UNIT CIRCUIT TESTNJGI0005S0306System Description: When the switch is ON, the control unit lights
up the lamp.
MGI034A
Input-output voltage chart
Pin No. Item ConditionVoltage
value VIn case of high resistance such as single strand V *
1 Switch Switch ON Battery voltage Lower than battery voltage Approx. 8 (Example)
Switch OFF Approx. 0 Approx. 0
2 Lamp Switch ON Battery voltage Approx. 0 (Inoperative lamp)
Switch OFF Approx. 0 Approx. 0
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 voltage. 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 light up the
lamp.
HOW TO PERFORM EFFICIENT DIAGNOSES FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont’d)
GI-30

NJGI0011
ISO 15031-2NJGI0011S01All emission related terms used in this publication in accordance with ISO15031-2 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 sensor BARO sensor ***
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 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 modification EM ***
Engine speed RPM Engine speedMA
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ISO 15031-2 TERMINOLOGY LIST
ISO 15031-2
GI-51

NEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
Erasable programmable read only
memoryEPROM ***
Evaporative emission canister EVAP canister Canister
Evaporative emission system EVAP system Evaporative emission control system
Exhaust gas recirculation valve EGR valve EGR valve
Exhaust gas recirculation control-BPT
valveEGRC-BPT valve BPT valve
Exhaust gas recirculation control-solenoid
valveEGRC-solenoid valve EGR control solenoid valve
Exhaust gas recirculation temperature
sensorEGRT sensor Exhaust gas temperature sensor
EGR temperature sensor
Flash electrically erasable programmable
read only memoryFEEPROM ***
Flash erasable programmable read only
memoryFEPROM ***
Flexible fuel sensor FFS ***
Flexible fuel system FF system ***
Fuel level sensor *** ***
Fuel pressure regulator *** Pressure regulator
Fuel pressure regulator control solenoid
valve*** PRVR control solenoid valve
Fuel tank temperature sensor FTT sensor Tank fuel temperature sensor
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
valveIACV-AAC valve Auxiliary air control (AAC) valve
Idle air control valve-FICD solenoid valve IACV-FICD solenoid valve FICDsolenoid valve
Idle air control valve-idle up control sole-
noid valveIACV-idle up control solenoid valve Idle 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
ISO 15031-2 TERMINOLOGY LIST
ISO 15031-2 (Cont’d)
GI-52

EC-5
C
D
E
F
G
H
I
J
K
L
M
ECA Wiring Diagram .................................................... 353
Diagnostic Procedure ........................................... 354
DTC P1706 PNP SWITCH ...................................... 356
Component Description ........................................ 356
CONSULT-II Reference Value in Data Monitor Mode
. 356
On Board Diagnosis Logic ................................... 356
DTC Confirmation Procedure ............................... 356
Overall Function Check ........................................ 357
Wiring Diagram .................................................... 358
Diagnostic Procedure ........................................... 359
DTC P1805 BRAKE SWITCH ................................ 360
Description ........................................................... 360
CONSULT-II Reference Value in Data Monitor Mode
. 360
On Board Diagnosis Logic ................................... 360
DTC Confirmation Procedure ............................... 360
Wiring Diagram .................................................... 361
Diagnostic Procedure ........................................... 362
Component Inspection ......................................... 364
IGNITION SIGNAL .................................................. 365
Component Description ........................................ 365
Wiring Diagram .................................................... 366
Diagnostic Procedure ........................................... 369
Component Inspection ......................................... 373
Removal and Installation ...................................... 374
INJECTOR CIRCUIT ............................................... 375
Component Description ........................................ 375
CONSULT-II Reference Value in Data Monitor Mode
. 375
Wiring Diagram .................................................... 376
Diagnostic Procedure ........................................... 377
Component Inspection ......................................... 380
Removal and Installation ...................................... 380
FUEL PUMP CIRCUIT ............................................ 381
Description ........................................................... 381
CONSULT-II Reference Value in Data Monitor Mode
. 381
Wiring Diagram .................................................... 382
Diagnostic Procedure ........................................... 383
Component Inspection ......................................... 385
Removal and Installation ...................................... 386
REFRIGERANT PRESSURE SENSOR ................. 387
Component Description ........................................ 387
Wiring Diagram .................................................... 388
Diagnostic Procedure ........................................... 389
Removal and Installation ...................................... 391
ELECTRICAL LOAD SIGNAL ................................ 392
Description ...................................................
........ 392
CONSULT-II Reference Value in Data Monitor Mode
. 392
Wiring Diagram .................................................... 393
Diagnostic Procedure ........................................... 394
MI & DATA LINK CONNECTORS .......................... 397
Wiring Diagram—LHD Models ............................. 397
Wiring Diagram—RHD Models ............................ 398
EVAPORATIVE EMISSION SYSTEM ..................... 399
Description ........................................................... 399
Component Inspection ......................................... 401POSITIVE CRANKCASE VENTILATION ...............402
Description ............................................................402
Component Inspection ..........................................402
SERVICE DATA AND SPECIFICATIONS (SDS) ....404
Fuel Pressure .......................................................404
Idle Speed and Ignition Timing .............................404
Calculated Load Value ..........................................404
Mass Air Flow Sensor ...........................................404
Intake Air Temperature Sensor .............................404
Engine Coolant Temperature Sensor ...................404
Heated Oxygen Sensor 1 Heater .........................404
Heated Oxygen sensor 2 Heater ..........................404
Crankshaft Position Sensor (POS) .......................404
Camshaft Position Sensor (PHASE) ....................404
Throttle Control Motor ...........................................405
Injector ..................................................................405
Fuel Pump ............................................................405
QG (WITHOUT EURO-OBD)
INDEX FOR DTC .....................................................406
Alphabetical Index ................................................406
DTC No. Index ......................................................407
PRECAUTIONS ......................................................409
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ...............................................................409
On Board Diagnostic (OBD) System of Engine ....409
Precaution ............................................................409
Wiring Diagrams and Trouble Diagnosis ..............412
PREPARATION .......................................................413
Special Service Tools ...........................................413
Commercial Service Tools ....................................413
ENGINE CONTROL SYSTEM ................................415
System Diagram ...................................................415
Vacuum Hose Drawing .........................................416
System Chart ........................................................417
Multiport Fuel Injection (MFI) System ...................417
Electronic Ignition (EI) System .............................419
Air Conditioning Cut Control .................................420
Fuel Cut Control (at No Load and High Engine
Speed) ..................................................................421
CAN Communication ............................................421
BASIC SERVICE PROCEDURE .............................424
Idle Speed and Ignition Timing Check ..................424
Accelerator Pedal Released Position Learning ....425
Throttle Valve Closed Position Learning ...............425
Idle Air Volume Learning ......................................425
Fuel Pressure Check ............................................427
ON BOARD DIAGNOSTIC (OBD) SYSTEM ..........429
Introduction ...........................................................429
Two Trip Detection Logic ......................................429
Emission-related Diagnostic Information ..............429
NATS (Nissan Anti-theft System) .........................431
Malfunction Indicator (MI) .....................................432
TROUBLE DIAGNOSIS ..........................................436
Trouble Diagnosis Introduction .............................436
DTC Inspection Priority Chart ...............................440
Fail-safe Chart ......................................................441