NISSAN LATIO 2009 Service Repair Manual

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• 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 To simplify the discussion of shorts in the system, please refer to the following schematic.
RESISTANCE CHECK METHOD
• Disconnect the battery negative cable and remove the blown fuse.
• Disconnect all loads (SW1 open, relay disconnected and solenoid disconnected) powered through the fuse.
• Connect one probe of the DMM to the load side of the fuse terminal. Connect the other probe to a known
good ground.
• 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.
• 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.
• Close SW1 and jump the relay contacts with jumper wir e. 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
• Remove the blown fuse and disconnect all loads (i .e. SW1 open, relay disconnected and solenoid discon-
nected) powered through the fuse.
• Turn the ignition key to the ON or START position. Veri fy battery voltage at the battery + side of the fuse ter-
minal (one lead on the battery + terminal side of the fuse block and one lead on a known good ground).
• 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.
• With SW1 closed, relay and solenoid disconnected and t he 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.
• 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 oper ation 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 re sistance can change the way a circuit works.
Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can drasti-
cally 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:
• Remove the ground bolt or screw.
• Inspect all mating surfaces for tarnish, dirt, rust, etc.

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Note in the illustration that there is an excessi
ve 4.1 volt drop between the battery and the bulb.
MEASURING VOLTAGE DRO P — 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 oper ations 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

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• Before installing a connector, make sure the terminal is not bent or
damaged, and then correctly connect it.
When installing a connector by tightening bolts, fix it by tightening
the mounting bolt until the painted projection of the connector
becomes even with the surface.
• For removal of the lever type connector, pull the lever up to the direction pointed to by the arrow A in the figure, and then remove
the connector.
• For installation of the lever type connector, pull down the lever to the direction pointed by the arrow B in the figure, and then push
the connector until a clicking noise is heard.
• 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.

GI-34< SERVICE INFORMATION >
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
• When using a DMM, be careful not to let test probes get close to each other to prevent the power tr ansistor 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. SEF348N

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CONSULT-III CHECKING SYSTEM
Description INFOID:0000000004307366
• 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 contro l 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 Application INFOID:0000000004307367
x: Applicable.
*1: If equipped.
*2: With automatic transmission (A/T).
*3: With continuously variable transmission (CVT).
*4: With security card installed. Diagnostic test mode FunctionENGINE
ABS* 1
AIR BAG EPS
IPDM E/R BCM
METER/M&A
INTELLIGENT KEY* 1
TRANSMISSION* 2
TRANSMISSION* 3
Work support This mode enables a technician to adjust some devices faster and
more accurately by following indications on CONSULT-III. x - - - - x - x x x
Self-diagnostic results Self-diagnostic results can be read and erased quickly. x x x x x x x x x x
Trouble diagnostic record Current 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. x x x x x x x x x x
CAN diagnostic support
monitor The communication condition of CAN communication line can be
read. x x - x x x x x x x
Calibration data* 2
Shows unit calibration IDs, offsets and gains. This data is stored in
the ECU memory. - - - - - - - - - x
Active test Diagnostic Test Mode in which CONSULT-III drives actuators apart
from ECU shifting some parameters in a specified range. x x - - x x - x - -
Function test This mode can show results of self-diagnosis of ECU with either
"OK" or "NG". For engines, more practical tests regarding sensors/
switches and/or actuators are available. x x x - - - - - x x
DTC & SRT confirmation The results of SRT (System Readiness Test) and the self-diagno-
sis status/result can be confirmed. x - - - - - - - x -
DTC work support The 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 - - - -
Control unit initialization *4
All registered ignition key IDs in NATS components can be initial-
ized and new IDs can be registered. - - - - - x - - - -
PIN Read *4
This mode enables technician to get BCM-specific 5-digit code. - - - - - x - - - -

B

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NOTE:
The DDL1 and DDL2 circuits from DLC pins 6, 7 and 14 may be connected to more than one system. A short
in a DDL circuit connected to a control unit in one syst em may affect CONSULT-III access to other systems.
Symptom Check item
CONSULT-III cannot access
any system. • CONSULT-III DLC power supply circuit (Terminal 8) and ground circuit (Terminal 4). For detailed cir-
cuit, refer to LAN-31, " Wiring Diagram - CAN - " .
CONSULT-III cannot access in-
dividual system. (Other sys-
tems can be accessed.) • Power supply and ground circuit for the control unit of the system (For detailed circuit, refer to wiring
diagram for each system).
• Open or short circuit between the system and CONSULT-III DLC (For detailed circuit, refer to wiring diagram for each system).
• Open or short circuit CAN communication line. Refer to LAN-31, " Wiring Diagram - CAN - " .