GI-18
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HOW TO USE THIS MANUAL
• Letter designations next to test meter probe indicate harness (con-
nector) wire color.
• Connector numbers in a single circle M33 indicate harness con-
nectors.
Component Indication
Connector numbers in a double circle F211 indicate component connectors.
Switch Positions
Switches are shown in wiring diagrams as if the vehicle is in the “normal” condition.
A vehicle is in the “normal” condition when:
• ignition switch is “OFF”,
• doors, hood and trunk lid/back door are closed,
• pedals are not depressed, and
• parking brake is released.
Detectable Lines and Non-Detectable Lines
In some wiring diagrams, two kinds of lines, representing wires, with different weight are used.
AGI070
SGI860
HOW TO USE THIS MANUAL
GI-19
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• A line with regular weight (wider line) represents a “detectable line
for DTC (Diagnostic Trouble Code)”. A “detectable line for DTC” is
a circuit in which ECM can detect its malfunctions with the on
board diagnostic system.
• A line with less weight (thinner line) represents a “non-detectable
line for DTC”. A “non-detectable line for DTC” is a circuit in which
ECM cannot detect its malfunctions with the on board diagnostic
system.
Multiple Switch
The continuity of multiple switch is described in two ways as shown below.
• The switch chart is used in schematic diagrams.
• The switch diagram is used in wiring diagrams.
Reference Area
SGI862-B
SGI875
GI-28
< SERVICE INFORMATION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
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 har-
ness or electrical component to do this.
NOTE:
Refer to “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 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).
OPEN A circuit is open when there is no continuity through a section of the circuit.
SHORTThere are two types of shorts.
• SHORT CIRCUITWhen 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.
SGI846-A
GI-30
< SERVICE INFORMATION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
• 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. Make sure all of the
wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eye-
let make sure no ground wires have excess wire insulation.
For detailed ground distribution information, refer 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 resistance 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 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
• Connect the DMM across the connector or part of the circuit 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.
SGI853
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
GI-31
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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 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.
Control Unit Circuit Test
System Description:When the switch is ON, the control unit lights up the lamp.
INPUT-OUTPUT VOLTAGE CHART
SGI974
SAIA0258E
MGI034A
GI-32
< SERVICE INFORMATION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
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.
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. 0V. Control 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 light up the lamp.
Control Units and Electrical PartsINFOID:0000000001702442
PRECAUTIONS
• Never reverse polarity of battery terminals.
• Install only parts specified for a vehicle.
• Before replacing the control unit, check the input and output and
functions of the component parts.
• Do not apply excessive force when disconnecting a connector.
• If a connector is installed by tightening bolts, loosen bolt mounting
it, then take it out by hand.
Pin
No.Item ConditionVo l ta g e
value [V]In case of high resistance such as single strand [V] *
1SwitchSwitch ON Battery voltage Lower than battery voltage Approx. 8 (Example)
Switch OFF Approx. 0 Approx. 0
2LampSwitch ON Battery voltage Approx. 0 (Inoperative lamp)
Switch OFF Approx. 0 Approx. 0
MGI035A
Pin
No.Item ConditionVo l ta g e
value [V]In case of high resistance such as single strand [V] *
1LampSwitch ON Approx. 0 Battery voltage (Inoperative lamp)
Switch OFF Battery voltage Battery voltage
2SwitchSwitch ON Approx. 0 Higher than 0 Approx. 4 (Example)
Switch OFF Approx. 5 Approx. 5
SAIA0251E
CONSULT-III CHECKING SYSTEM
GI-35
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PCONSULT-III CHECKING SYSTEM
DescriptionINFOID:0000000001806209
• CONSULT-III is a hand-held type tester. When it is connected with a diagnostic connector equipped on the
vehicle side, it will communicate with the control unit equipped in the vehicle and then enable various kinds
of diagnostic tests.
• Refer to CONSULT-III Operator's Manual for more information.
Function and System ApplicationINFOID:0000000001806219
x: Applicable.
*1: If equipped.
*2: This option is shown on vehicles equipped with continuously variable transmission (CVT).
*3: NVIS (NATS) [NISSAN Vehicle Immobilizer System (Nissan Anti-theft System)]. Diagnostic test mode Function
ENGINE
ABS*
1
AIR BAG
EPS
IPDM E/R
BCM
METER/M&A
INTELLIGENT KEY*
1
A/T*
1
TRANSMISSION*
2
NVIS (NATS)*
3
NVIS (NATS BCM OR S/ENT)*
3
NATS I-KEY
*3,5
Work supportThis mode enables a technician to adjust some devices faster
and more accurately by following indications on CONSULT-III.x----x-xxx--x
Self-diagnostic results Self-diagnostic results can be read and erased quickly. xxxxxxxxxxx - x
Trouble diagnostic
recordCurrent self-diagnostic results and all trouble diagnostic records
previously stored can be read.--x----------
Data monitor Input/Output data in the ECU can be read. xx - xx - xxxx - - -
CAN diagnostic support
monitorThe communication condition of CAN communication line can
be read.xx - xxxxxxx - - -
Calibration data*
2Shows unit calibration IDs, offsets and gains. This data is stored
in the ECU memory.---------x---
Active testDiagnostic Test Mode in which CONSULT-III drives actuators
apart from ECU shifting some parameters in a specified range.xx--x--x-----
Function testThis mode can show results of self-diagnosis of ECU with either
"OK" or "NG". For engines, more practical tests regarding sen-
sors/switches and/or actuators are available.xxx-----xx---
DTC & SRT confirmationThe results of SRT (System Readiness Test) and the self-diag-
nosis status/result can be confirmed.x------------
DTC work supportThe operating condition to confirm Diagnosis Trouble Codes
can be selected.x-------x----
ECM/ECU part number ECM/ECU part number can be read. x x - x - x - x x x - - -
ECU discriminated No.Classification number of a replacement ECU can be read to pre-
vent an incorrect ECU from being installed.--x----------
Passenger airbag Displays the STATUS (readiness) of front passenger air bag. --x----------
Configuration Sets control module parameters to match vehicle options. -----x-------
Steering lock release
*4,5Condition of steering lock release solenoid. -----------x-
Control unit initializa-
tion
*4,6All registered ignition key IDs in NATS components can be ini-
tialized and new IDs can be registered.----------x--
PIN Read
*4This mode enables technician to get BCM-specific 5-digit code.-----------x-
TERMINOLOGY
GI-47
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PTERMINOLOGY
SAE J1930 Terminology ListINFOID:0000000001702459
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.
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-III DLC for CONSULT-III Diagnostic connector for CONSULT-III
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 speed
Erasable programmable read only memory EPROM ***
Evaporative emission canister EVAP canister Canister
Evaporative emission system EVAP system Canister control solenoid valve
Exhaust gas recirculation valve EGR valve EGR valve