NISSAN LATIO 2011 Service Repair Manual

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The customer's concern 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 com ponent is heat sensitive, heat the
component with a heat gun or equivalent.
Do not heat components above 60 °C (140° F). If incident occurs
while heating the unit, either replace or properly insulate the compo-
nent.
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 outside
overnight. In the morning, do a quick and thorough diagnosis 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 intru-
sion on an electrical part. This c an 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.
CIRCUIT INSPECTION
Introduction
In general, testing electrical circuits is an easy ta sk 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 thor-
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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 symbo\
l). Make sure to always start
with the DMM at the highest resistance level.
To help in understanding the diagnosis of open circui ts, 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, t he 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 ci rcuit, 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 circui ts please refer to the previous schematic.
In any powered circuit, an open can be found by methodica lly 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.
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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• 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 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.
• 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 resistance 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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• 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 thewires 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 resist ance 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.
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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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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 ligh t 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. Cont rol 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 u p the lamp.
Control Units and Electrical PartsINFOID:0000000005929729
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 Condition
Vo l ta g e
value [V] In case of high resistance such as single strand [V] *
1Switch Switch ON Battery voltage Lower than battery voltage Approx. 8 (Example)
Switch OFF Approx. 0
Approx. 0
2Lamp Switch ON Battery voltage App
rox. 0 (Inoperative lamp)
Switch OFF Approx. 0 Approx. 0
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Pin
No. Item Condition
Vo l ta g e
value [V] In case of high resistance such as single strand [V] *
1Lamp Switch ON Approx. 0
Battery voltage (Inoperative lamp)
Switch OFF Battery voltage Battery voltage
2Switch Switch ON Approx. 0
Higher than 0 Approx. 4 (Example)
Switch OFF Approx. 5 Approx. 5
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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.
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• When using a DMM, be careful not to let test probes get close toeach other to prevent the power transistor 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.
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CONSULT-III CHECKING SYSTEMGI-35
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O PCONSULT-III CHECKING SYSTEM
DescriptionINFOID:0000000005929730
• 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 ApplicationINFOID:0000000005929731
x: Applicable.
*1: If equipped.
*2: With automatic transmission (A/T).
*3: With continuously variable transmission (CVT). Diagnostic test mode
Function
ENGINE
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. xx - - - x - - xx
Self Diagnostic Result Self-diagnostic results can be read and erased quickly. x x x x x x x x x 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.
xx - xxxxxxx
Active Test Diagnostic Test Mode in which CONSULT-III drives actuators apart
from ECU shifting some parameters in a specified range. xx - - xx - 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. xxx - - - - - xx
DTC & SRT Confirmation The results of SRT (System Readiness Test) and the self-diagno-
sis status/result can be confirmed. x---------
Ecu Identification ECM/ECU part number can be read. x x x x - x - x x x
Configuration Sets control module parameters to match vehicle options. - - - - - x - - - -
Special Function Other results or histories, etc that are recorded in ECU are dis-
played. --x-----xx
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CONSULT-III CHECKING SYSTEM
CONSULT-III Data Link Connector (DLC) Circuit
INFOID:0000000005929732
INSPECTION PROCEDURE
If the CONSULT-III cannot diagnose the syst em properly, check the following items.
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