1995 NISSAN ALMERA N15 Service Manual

TROUBLEDIAGNOSIS -General Description
Sensors
~ ECMActuators
~~.~ MEF036D
SEF234G Introduction

The engine hasanECM tocontrol majorsystems suchasfuel
control, ignitioncontrol, idleaircontrol system, etc.The ECM
accepts inputsignals fromsensors andinstantly drivesactua-
tors. Itis essential thatboth input andoutput signals areproper
and stable. Atthe same time,itis important thatthere areno
problems suchasvacuum leaks,fouled sparkplugs, orother
problems withtheengine.
It is much moredifficult todiagnose aproblem thatoccurs
intermittently ratherthancontinuously. Mostintermittent prob-
lems arecaused bypoor electric connections orimproper wir-
ing. Inthis case, careful checking ofsuspected circuitsmay
help prevent thereplacement ofgood parts.
A visual checkonlymaynotfind thecause ofthe problems. A
road testwith CONSULT oracircuit testerconnected shouldbe
performed. Followthe"Work Flow"onthe next page.
Before undertaking actualchecks, takejustafew minutes to
talk with acustomer whoapproaches withadriveability com-
plaint. Thecustomer cansupply goodinformation aboutsuch
problems, especially intermittent ones.Findoutwhat symptoms
are present andunder whatconditions theyoccur. A"Diagnos-
tic Worksheet" liketheexample onEC-61 should beused.
Start yourdiagnosis bylooking for"conventional" problems
first. Thiswillhelp troubleshoot driveabilityproblemsonan
electronically controlledenginevehicle.

EC-58

TROUBLEDIAGNOSIS -General Description
Work Flow
CHECK IN
Listen tocustomer complaints. (Getsymptoms.)
................................................STEPI
Check, printoutorwrite down, anderase Diagnostic TroubleCode(DTC).
Symptoms
collected. No
symptoms, but
Malfunction Code
exists atSTEP II. ..
STEPII

•

Verify
thesymptom bydriving inthe conditiOn the
customer described. *1
......................................................................................... STEPIII
Normal Code
(at STEP II) Malfunction
Code
(at STEP II)
Verify theDTC byperforming the"DTC CONFIRMATION PROCEDURE".
Choose theappropriate action.
Malfunction Code(atSTEP IIor IV) Normal Code(atboth STEP IIand IV)
BASIC INSPECTION
SYMPTOM BASIS(atSTEP Ior III)
Perform inspections
according toSymptom
Matrix Chart. *1
.. STEPIV
. STEPV
*2
TROUBLE DIAGNOSIS FORDTCXX. STEP
VI
REPAIR/REPLACE
NG FINAL CHECK
Confirm thattheincident iscompletely fixedbyperforming BASICINSPECTION
and DTC CONFIRMATION PROCEDURE(orOVERALL FUNCTION CHECK). ..........................................
STEPVII
CHECK OUT
*1: Ifthe incident cannotbeduplicated, refertoGI section ("Incident Simulation Tests","HOWTOPERFORM EFFICIENT DIAG-
NOSIS FORANELECTRICAL INCIDENT").
*2: Ifthe on-board diagnostic systemcannotbeperformed, checkmainpower supply andground circuit.Referto"TROUBLE
DIAGNOSIS FORPOWER SUPPLY", EC-88.
EC-59

STEP
STEP I
STEP II
STEP III
STEP IV
STEP V
STEP VI
STEP VII
TROUBLE
DIAGNOSIS -General oescrip_ti_on
I_G_A_'

Description forWork Flow

DESCRIPTION
Get detailed information abouttheconditions andtheenvironment whentheincident/symptom occurred
using the"DIAGNOSTIC WORKSHEET" asshown onthe next page.
Before confirming theconcern, checkandwrite down (printoutusing CONSULT) theDiagnostic Trouble
Code (DTC), thenerase thecode. TheDTC canbeused when duplicating theincident atSTEP III
&
IV.
Study therelationship betweenthecause, specified byDTC, andthesymptom described bythe customer.
(The "Symptom MatrixChart" willbeuseful. RefertoEC-72.)
Try toconfirm thesymptom andunder whatconditions theincident occurs.
The "DIAGNOSTIC WORKSHEET" isuseful toverify theincident. ConnectCONSULT tothe vehicle inDATA
MONITOR (AUTOTRIG)modeandcheck realtime diagnosis results.
If the incident cannotbeverified, performINCIDENT SIMULATION TESTS.RefertoGI section.
If the malfunction codeisdetected, skipSTEP IVand perform STEPV.
Try todetect theDiagnostic TroubleCode(DTC) bydriving in(or performing) the"DTC CONFIRMATION
PROCEDURE". Checkandread theDTC byusing CONSULT.
During theDTC verification, besure toconnect CONSULT tothe vehicle inDATA MONITOR (AUTOTRIG)
mode andcheck realtime diagnosis results.

If
the incident cannotbeverified, performINCIDENT SIMULATION TESTS.RefertoGI section.
In case the"DTC CONFIRMATION PROCEDURE"isnot available, performthe"OVERALL FUNCTION
CHECK" instead.TheDTC cannot bedisplayed bythis check, however, thissimplified "check"isan effec-
tive alternative.
The "NG" result ofthe "OVERALL FUNCTIONCHECK"isthe same asthe DTC detection.
Take theappropriate actionbasedonthe results ofSTEP Ithrough IV.
If the malfunction codeisindicated, proceedtoTROUBLE DIAGNOSIS FORDTCXX.
If the normal codeisindicated, proceedtothe BASIC INSPECTION. RefertoEC-65. Thenperform inspec-
tions according tothe Symptom MatrixChart.RefertoEC-72.
Identify wheretobegin diagnosis basedonthe relationship studybetween symptom andpossible causes.
Inspect thesystem formechanical binding,looseconnectors orwiring damage using(tracing) "Harness
Layouts".
Gently shaketherelated connectors, components orwiring harness withCONSULT setin"DATA MONITOR
(AUTO TRIG)" mode.
Check thevoltage ofthe related ECMterminals ormonitor theoutput datafrom therelated sensors with
CONSULT. RefertoEC-74.
The "DIAGNOSTIC PROCEDURE" inEC section contains adescription basedonopen circuit inspection. A
short circuit inspection isalso required forthe circuit checkinthe DIAGNOSTIC PROCEDURE. Fordetails,
refer toGI section ("HOWTOPERFORM EFFICIENT DIAGNOSIS FORANELECTRICAL INCIDENT","Circuit
Inspection' ').
Repair orreplace themalfunction parts.
Once youhave repaired thecircuit orreplaced acomponent, youneed torun theengine inthe same condi-
tions andcircumstances whichresulted inthe customer's initialcomplaint.
Perform the"DTC CONFIRMATION PROCEDURE"andconfirm thenormal code(Diagnostic troublecodeNo.
55) isdetected. Ifthe incident isstill detected inthe final check, perform STEPVIby using adifferent
method fromtheprevious one.
Before returning thevehicle tothe customer, besure toerase theunnecessary (alreadyfixed)DTCinECM.
Refer toEC-46.

EC-60

TROUBLEDIAGNOSIS -General Description

KEY POINTS
WHAT .....Vehicle &engine model
WHEN Date,Frequencies
WHERE Roadconditions
HOW Operatingconditions,
Weather conditions,
Symptoms
SEF907L
WORKSHEET SAMPLE
Diagnostic
Worksheet

There aremany operating conditions thatlead tothe malfunc-
tion ofengine components. Agood grasp ofsuch conditions can
make troubleshooting fasterandmore accurate.
In general, eachcustomer feelsdifferently aboutaproblem. It
is important tofully understand thesymptoms orconditions for
a customer complaint.
Utilize adiagnostic worksheet liketheone shown belowin
order toorganize allthe information fortroubleshooting.

•

Customer name
MR/MS Model
&
Year
.

VIN
Engine
#
Trans. Mileage
Incident Date Manu!.Date InService Date

o
Impossible tostart
o

No combustion

o
Partial combustion

o
Startability
o

Partial combustion affectedbythrottle position
LJ Partial combustion NOTaffected bythrottle position

o
Possible buthard tostart
o
Others [

1

o
Idling
o

No fast idle
o
Unstable
o

High idle
o
Low idle

o
Others [

1

Symptoms

o
Stumble
o
Surge
o
Knock
o
Lack ofpower

o
Driveability
i.J
Intake backfire
o
Exhaust backfire

o
Others [

1

o
At the lime ofstart
o

While idling

[.J
Engine stall

o
While accelerating
o

While decelerating

o
Just after stopping
o

While loading
Incident occurrence
o

Just after delivery
o
Recently

o
Inthe morning
o
At night
o
Inthe daytime
Frequency
o
All the time
o

Under certain conditions

o
Sometimes
Weather conditions
o
Not affected
Weather
o
Fine DRaining
o
Snowing
o
Others [

1

Temperature
o
Hot
o
Warm
o
Cool
o

Cold

o
Humid OF

o
Cold
o
During warm-up
o
After warm-up
Engine conditions
Enginespeed

I
I
I
I

I
I
I

I

I

0 2,000 4,000
6,000 8,000
rpm

Road conditions
o
Intown
o
Insuburbs
o

Highway

o
Off road (up/down)

o
Not affected

o
At starting
o
While idling
o
At racing

o
While accelerating
o
While cruising
Driving conditions
o

While decelerating
o

While turning (RH/LH)
Vehicle speed
I
,

I
I
I III
I
I
I
II

0 10 20 30
40
5060
MPH

Malfunction indicatorlamp
o
Turned on
o
Not turned on

EC-61

TROUBLEDIAGNOSIS -General Description
Diagnostic TroubleCode(DTC) Chart
ENGINE RELATED ITEMS

Detected items
Diagnostic
trouble code
(ScreentermsforCONSULT, Malfunction
isdetected when...
No. "SELF-DIAG RESULTS"mode)
11 Camshaftpositionsensorcircuit
•Either
l'
or 180' signal isnot detected bythe ECM forthe first few
(CAMSHAFT POSISEN)
secondsduringengine cranking .
• Either
l'
or 180' signal isnot detected bythe ECM often enough
while theengine speedishigher thanthespecified rpm.
• The relation between
l'
and 180' signals isnot inthe normal range
during thespecified rpm.
12 Massairflow sensor circuit
•An excessively highorlow voltage isentered toECM.
(MASS AIRFLOW SEN) •Voltage senttoECM isnot practical whencompared withthecam-
shaft position sensorsignalandthrottle position sensorsignal.
13 Enginecoolant temperature sen-•An excessively highorlow voltage fromthesensor isdetected by
sor circuit
theECM.
(COOLANT TEMPSEN)
21 Ignitionsignalcircuit
•The ignition signalinthe primary circuitisnot detected bythe ECM
(IGN SIGNAL-PRIMARY)
duringengine cranking orrunning .
28*1 OVERHEAT •The engine coolant temperature sensoroutputvoltage isbelow
0.35V .
34"2 Knocksensor circuit •An excessively loworhigh voltage fromthesensor isdetected by
(KNOCK SENSOR) theECM.
41 *3 Intakeairtemperature sensorcir-•An excessively highorlow voltage fromthesensor isdetected by
cuit theECM.
(INT AIRTEMP SEN) •Voltage senttoECM isnot practical whencompared withtheengine
coolant temperature sensorsignal.

55
Nofailure •No malfunction isdetected bythe ECM.
(NO SELF DIAGNOSTIC FAILURE
INDICATED ...)
"1: Except forAustralia
*2: Except forEurope andIsrael
"3: For Australia
*4: This isQuick Reference of"DTC CONFIRMATION PROCEDURE".
Details aredescribed ineach TROUBLE DIAGNOSIS FORDTCXX
Abbreviations areasfollows:
IGN: ON :Turning theignition switchONisrequired forthe ECM todetect amalfunction (ifone exists).
RUNNING: Runningengineisrequired forthe ECM todetect amalfunction (ifone exists).
*5: •The "OVERALL FUNCTIONCHECK"isasimplified andeffective waytoinspect acomponent orcircuit.
In some cases, the"OVERALL FUNCTIONCHECK"isused rather thana"DIAGNOSTIC TROUBLECODECONFIRMA-
TION PROCEDURE".
When noDTC CONFIRMATION PROCEDUREisavailable, the"NG" result ofthe OVERALL FUNCTION CHECKcanbe
considered tomean thesame asaDTC detection .
• During an"NG" OVERALL FUNCTION CHECK,theDTC might notbeconfirmed.

EC-62

TROUBLEDIAGNOSIS -General Description
mJ

Diagnostic TroubleCode(DTC) Chart(Cont'd)

X:Applicable
-: Not applicable
"DTC *4
*5
Check Items CONFIRMATION
"OVERALLFUNC-Fail ReferencePage
(Possible Cause) PROCEDURE"
TIONCHECK" Safe
Quick Ref. QuickRef. System
• Harness orconnectors
(The sensor circuitisopen orshorted.)
• Camshaft positionsensor
RUNNING EC-94

-
-

• Starter motor
• Starting systemcircuit(ELsection)
• Dead (Weak) battery
• Harness orconnectors
.

(The sensor circuitisopen orshorted.) RUNNING
RUNNING
X
EC-101
• Mass airflow sensor
• Harness orconnectors
(The sensor circuitisopen orshorted.) IGN:ON
-

X
EC-108
• Engine coolant temperature sensor
• Harness orconnectors
(The ignition primary circuitisopen orshorted.)
• Power transistor unit RUNNING
-
-
EC-113
• Camshaft positionsensor
• Camshaft positionsensorcircuit
• Harness orconnector IGN:
ON
EC-108

- -

• Engine coolant temperature sensor (after
warming up)
• Harness orconnectors
(The sensor circuitisopen orshorted.) RUNNING
-
-
EC-119
• Knock sensor
• Harness orconnectors
(The sensor circuitisopen orshorted.)
IGN:ON
-
-
EC-124
• Intake airtemperature sensor
• No failure

----

EC-63
•

TROUBLEDIAGNOSIS -General Description
Fail-Safe Chart

The ECM enters fail-safe mode,ifany ofthe following DTCsisrecorded duetothe open orshort circuit.

DTC No. Detected
items
Engineoperating conditioninfail-safe mode
12 Massairflow sensor
Enginespeedwillnotrise more than3,000 rpm*1 duetothe fuel cut.
circuit
13 Engine
coolant tem-
Engine coolant temperature willbedetermined basedonthe time after turning ignition
perature sensorcir-switch "ON"or"START".
cuit ExceptforEurope andIsrael
Condition Enginecoolant temperature decided
Just asignition switchisturned ONorStart 30'C(B6'F)
More than5minutes afterignition ONorStart BO'G
(176'F)
Except asshown above 30
-BO'C (B6-176'F)
(Depends onthe time)
For Europe andIsrael
Condition Enginecoolant temperature decided
Just asignition switchisturned ONorStart 35'C
(95'F)
More than4.5minutes afterignition ONor
BO'G(176'F)
Start
Except asshown above 35
-BO'C (95-176'F)
(Depends onthe time)
When thefail-safe systemforengine coolant temperature sensorisactivated, thecooling
fan operates whileengine isrunning.
43 Throttle position Throttle
position willbedetermined basedonthe injected fuelamount andtheengine
sensor circuit speed.
Therefore, acceleration willbepoor.
Condition Driving
condition
When engine isidling Normal
When accelerating Poor
acceleration

-
ECM
Fail-safe
systemactivating conditionwhenECMismalfunctioning

The computing functionofthe ECM wasjudged tobe malfunctioning.
When thefail-safe systemactivates (i.e.,ifthe ECM detects amalfunction conditionin
the CPU ofECM), theMALFUNCTION INDICATORLAMPonthe instrument panellightsto
warn thedriver.

Engine control, withfail-safe system,operates whenECMismalfunctioning

When thefail-safe systemisoperating, fuelinjection, ignitiontiming,fuelpump
operation, IACV-AACvalveoperation andcooling fanoperation arecontrolled undercer-
tain limitations.
Operation

Engine speed Engine
speed
will
notrise more than3,000 rpm

Fuel injection Simultaneous
multipartfuelinjection system
Ignition timing Ignition
timingisfixed atthe preset valve
Fuel pump Fuel
pump' relayis"ON" when engine isrunning and"OFF" whenengine
stalls
IACV-AAG valve Full
open
Cooling fans Cooling
fanrelay "ON" whenengine isrunning, and"OFF" whenengine
stalls
EC-64

TROUBLEDIAGNOSIS -General Description

Goto
(J.

Adjust ignition timingby
turning distributor.

No
NG

(Go to
@
onnext page.)

OK
CONNECT
CONSULTTOTHE VEHICLE.

Connect "CONSULT" tothe data link
connector forCONSULT andselect
"ENGINE" fromthemenu. Referto

EC-36
DOES ENGINE START?
BEFORE
STARTING

1. Check service records forany recent
repairs thatmay indicate arelated •
problem, orthe current needfor
scheduled maintenance.
2. 9pen engine hoodandcheck thefol.
lowing:
• Harness connectors forimproper con-
nections
• Vacuum hosesforsplits, kinks,or
improper connections
• Wiring forimproper connections,
pinches, orcuts

CHECK IGNITION TIMING.

1. Warm upengine sufficiently.
2. Stop engine anddisconnect throttle
position sensorharness connector.
3. Start engine.
4. Check ignition timingatidle using
timing light.

Ignition liming:

Refer toEC-36.
Basic
Inspection
Precaution:
Perform BasicInspection withoutelectrical or
mechanical loads

applied;
• Headlamp switchisOFF,
• Air conditioner switchisOFF,
• Rear defogger switchisOFF,
• Steering wheelisin the straight-ahead position,etc.

m

\\

~
~ SEF1421

~use box

~-~

vll-JI-
Datalinkconnector~'

EC-65