1995 NISSAN ALMERA N15 Throttle

POSITIVECRANKCASE VENTILATION
Description

This system returnsblow-by gastothe intake
manifold collector.
The positive crankcase ventilation (PCV)valveis
provided toconduct crankcase blow-bygastothe
intake manifold.
During partialthrottle operation ofthe engine, the
intake manifold suckstheblow-by gasthrough
the
pev
valve.
Normally, thecapacity ofthe valve issufficient to
handle anyblow-by andasmall amount ofventi-
lating air.
The ventilating airisthen drawn fromtheairduct into
thecrankcase. Inthis process theairpasses
through thehose connecting airinlet tubes to
rocker cover.
Under full-throttle condition,themanifold vacuum
is insufficient todraw theblow-by flowthrough
the valve. Theflow goes through thehose con-
nection inthe reverse direction.
On vehicles withanexcessively highblow-by, the
valve doesnotmeet therequirement. Thisis
because someofthe flow willgothrough the
hose connection tothe intake manifold collector
under allconditions.

Oil separator

q
Freshair
.. Blow-by gas

ct>
Blow-by gasduring
high-load operation Baffle
plate
PCV
valve operation

Engine notrunning
or backfiring Cruising

~~
.0

Idling or Acceleration
or
decelerating high
load

-~--
.~
AEC923
Inspection
PCV (Positive Crankcase Ventilation)

With engine running atidle, remove PCVvalve fromrocker
cover. Aproperly workingvalvemakes ahissing noiseasair
passes through it.Astrong vacuum shouldbefelt immediately
when afinger isplaced overthevalve inlet.

AEC911 VENTILATION HOSE

1. Check hosesandhose connections forleaks.
2. Disconnect allhoses andclean withcompressed air.Ifany
hose cannot befreed ofobstructions, replace.

ET277 EC-240

BASICSERVICE PROCEDURE
Idle Speedllgnition TiminglldleMixtureRatio
Adjustment
PREPARATION

• Make surethatthefollowing partsarein
good order.
(1) Battery
(2) Ignition system
(3) Engine oiland coolant levels
(4) Fuses
(5) ECM harness connector
(6) Vacuum hoses
(7) Airintake system
(Oil filler cap,oillevel gauge, etc.)
(8) Fuel pressure
(9) Engine compression
(10) Throttle valve

Overall inspection sequence

INSPECTION
•
•
•
•
•
•
On
models equipped withairconditioner,
checks shouldbecarried outwhile theair
conditioner is"OFF".
On models equipped withautomatic
transaxle, whenchecking idlespeed, ignition
timing andmixture ratio,checks shouldbe
carried outwhile shiftlever isin "N" position.
When measuring "CO"percentage, insert
probe morethan40cm (15.7 in)into tailpipe.
Turn offheadlamps, heaterblower, rear
defogger. Keep frontwheels pointed straight ahead.
Make thecheck afterthecooling fanhas
stopped.
•

Perform diagnostic testmode II
(Self-diagnostic results).

OK

Check
&
adjust ignition timing.
Check
&
adjust idlespeed.
Check heated oxygen sensor
function. NG
Repair orreplace.
NG Check heated oxygen sensor
harness. NG
Repair orreplace harness.
OK OK
Check CO%. OKReplace heatedoxygen sensor.

NG

INSPECTION END Check
emission controlparts
and repair orreplace ifneces-
sary.

EC-243
NG
Check heated oxygen sensor
function.
OK

@

START
Visually checkthefollowing:
• Air cleaner clogging
• Hoses andduct forleaks
• Electrical connectors
• Gasket (intakemanifold, cylinderhead,exhaust system)
• Throttle valveandthrottle position sensoroperation

m
Start engine andwarm itup until engine coolant temperature indicator
points tothe middle ofgauge.
Ensure enginespeedstaysbelow 1,000rpm.

1

Open engine hoodandrunengine atabout 2,000rpmforabout 2minutes
under no-load.

Ii]
Perform theDiagnostic TestMode
1\
(Self-diagnostic results).
OK ~NG
Repair orreplace components asneces-
sary.

[!J
Run engine atabout 2,000rpmforabout 2minutes underno-load.
Rev engine twoorthree times under no-load, thenrunengine atidle
speed forabout 1minute .

li]1!I
00
1.
Select "IGNITION TIMINGADJ"inWORK SUPPORT mode.
2. Touch "START" .

.

OR

00
1.
Turn offengine anddisconnect throttleposition sensorharness
connector.
2. Start engine.
Rev engine (2,000-3,000 rpm)2or 3times under no-load, thenrunengine
at idle speed.

t

Throttle position sensor
harness connector SEF785KASEF051PA
BASIC
SERVICE PROCEDURE Em
Idle Speedllgnition TiminglldleMixtureRatio
Adjustment (Cont'd)
SEF248F
SEF455Q
Malfunction indicator
lamp \
I/

'~,,/

- CHECK-

,,/
........

/ I\
Ii] •IGN TIMING ADJ.
D
IGNITION TIMINGFEEDBACK
CONTROL WILLBEHELD BY
TOUCHING START.
AFTER DOING SO,ADJUST
IGNITION TIMINGWITHA
TIMING LIGHTBYTURNING
THE CAMSHAFT POSITION
SENSOR.

I
START

I

SEF546N
EC-244

AEC804
•

Ii

L

Check ignition timingwithatiming light.

M/T:
15°::l:2°BTDC
A/T: 15°::l: 2°BTDC (inUN" position)
NG
Adjust ignition timingtothe specified valuebyturning
distributor afterloosening boltswhich secure distribu-
tor.

M/T:
15°::l:2°BTDC

.
A/T:
15°::l: 2°BTDC (inUN" position)

~IIJ
@
~

00
1.
Select
"IGNTIMING ADJ"in"WORK
SUPPORT" mode.
2. Touch "START".
OR

@
1.
Stop engine anddisconnect throttleposition
sensor harness connector.
2. Start engine.

0
Check idlespeed.
@ Read
idlespeed in"IGN TIMING ADJ"in
"WORK SUPPORT" mode.
OR

@
Checkidlespeed.

M/T:
750::l: 50rprn
A/T: 750::l: 50rprn (inUN" position)
OK NG
Rev engine (2,000-3,000 rpm)2or 3times under
no-load, thenrunengine atidle speed.

1.1
Adjust idlespeed byturning idlespeed adjusting
screw.

M/T:
750::l: 50rpm
A/T: 750::l: 50rprn (inUN" position)

II
00
Touch
"BACK".
OR

@
1.
Turn offengine andconnect throttleposition
sensor harness connector.
2. Start engine.

L

Rev engine (2,000-3,000 rpm)2or 3times under
no-load, thenrunengine atidle speed.

-.

BASIC
SERVICE PROCEDURE
[]K]

Idle Speed/Ignition Timing/IdleMixtureRatio
Adjustment (Cont'd)

@

SEF548N

/ / I

Throttle position sensor-
harness connector /
I

\ \ SEF788LASEF546N

START

•
IGN TIMING ADJ.
0

IGNITION TIMINGFEEDBACK
CONTROL WILLBEHELD BY
TOUCHING START
AFTER DOING SO,ADJUST
IGNITION TIMINGWITHA
TIMING LIGHTBYTURNING
THE CAMSHAFT POSITION
SENSOR

= ==
MONITOR
==
=

CMPS.RPM (REF)762rpm
IGN TIMING 15BTDC
CLOSED TH/POS ON

Ii

o •
IGN TIMING ADJ.
0

I- -
CONDITION SETIING--
IGN/T FEEDBACK HOLD
EC-245

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION ~

Malfunction IndicatorLamp(MIL)(Cont'd)

DIAGNOSTIC TESTMODE I-BULB CHECK

In this mode, theMALFUNCTION INDICATORLAMPonthe instrument panelshould stayON.If
it
remains
OFF, check thebulb. Refer toEL section ("WARNING LAMPSANDCHIME") orsee EC-370.

DIAGNOSTIC TESTMODE I-MALFUNCTION WARNING
MALFUNCTION INDICATORLAMP
ON
OFF Condition
Engine coolant temperature sensorcircuitmalfunction isdetected, orthe ECM's CPU
is malfunctioning.
No malfunction.

• These Diagnostic TroubleCodeNumbers areclarified inDiagnostic TestMode II(SELF-DIAGNOS-
TIC RESULTS).

DIAGNOSTIC TESTMODE II-SELF-DIAGNOSTIC RESULTS

In this mode, adiagnostic troublecodeisindicated bythe number ofblinks ofthe MALFUNCTION INDI-
CATOR LAMPasshown below.

Example: Diagnostic troublecodeNo.12and No.43

0.6 0.3

ON
1111

OFF ~
0.9 0.3
0.6

--I~
2.1 0.6
0.9
0.3

Unit:second
Diagnostic troublecodeNo.12 Diagnostic
troublecodeNo.43

AEC490
• SELF-DIAG RESULTS.
0

FAILURE DETECTED TIME
NATS MALFUNCTION

0

I
ERASE

II
PRINT

I

SEF288Q

Long
(0.6second) blinkingindicates thenumber often digits, andshort (0.3second) blinkingindicates
the number ofsingle digits.Forexample, themalfunction indicatorlampblinks 4times forabout 2.5
seconds (0.6secx4times) andthen itblinks threetimes forabout 1second (0.3sec x3 times). This
indicates theDTC "43" andrefers tothe malfunction ofthe throttle position sensor.
In this way, allthe detected malfunctions areclassified bytheir diagnostic troublecodenumbers. The
DTC "55" refers tono malfunction. (SeeDIAGNOSTIC TROUBLECODECHART, refertoEC-268.)

HOW TOERASE DIAGNOSTIC TESTMODE II(Self-diagnostic results)

The diagnostic troublecodecanbeerased fromthebackup memory inthe ECM when thediagnostic
test mode ischanged fromDiagnostic TestMode IIto Diagnostic TestMode
I.
(Refer to"HOW TO
SWITCH DIAGNOSTIC TESTMODES" onprevious page.)
• Ifthe battery terminal isdisconnected, thediagnostic troublecodewillbelost from thebackup
memory within24hours.
• Becareful nottoerase thestored memory beforestarting- troublediagnoses.
• Ifthe MIL blinks or"NATS MALFUNCTION" isdisplayed on
"SELF-OIAG RESULTS"screen,perform self-diagnostic
results modewithCONSULT usingNATS program card
(NA TS-E940). RefertoEL section.
• Confirm noself-diagnostic resultsofNATS isdisplayed
before touching "ERASE" in"SELF-DiAG RESULTS"mode
with CONSULT.
• When replacing ECM,inltialisation ofNATS V2.0system and
registration ofall NATS V2.0 Ignition keyIDsmust becar-
ried outwith CONSULT usingNATS program card(NATS-
E940).
Therefore, besure toreceive allkeys from vehicle owner.
Regarding theprocedures ofNATS initialisation andNATS
ignition key
10
registration, refertoCONSULT operation
manual, NATS V2.0.

EC-252

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION
CONSULT (Coni'd)
ECCS COMPONENT PARTS/CONTROL SYSTEMSAPPLICATION
DIAGNOSTIC TESTMODE
SELF.
Item WORKDlAG.
DATAACTIVEFUNCTION
SUPPORT NOSTICMONITOR TESTTEST
RESULTS
Camshaft positionsensor XX
Mass airflow sensor XX
Engine coolant temperature sensor XX
X
Heated oxygen sensor X
X
Vehicle speedsensor X
X
Throttle positionsensor X
XX X
INPUT Knocksensor X

lJ)

~ Ignitionswitch(startsignal) X
X
a:

<

0-
Airconditioner switch X
~

z
Park/Neutralpositionswitch X
X

w

z

0
Powersteering oilpressure switch X
X

0-

:!
X

0
Battery
voltage

0

lJ)
Injectors XX
X

0
0
X(Ignition

w

Powertransistor (Iynitiontiming) X
XX
X
signal)
IACV-AAC valve XX
XX
OUTPUT Air
conditioner relay X
Fuel pump relay XXX
X
Cooling fan X
X
X
EGR valve
&
EVAP canister purge

X
X
X
control solenoid valve
X: Applicable
EC-255
•

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION
CONSULT (Cont'd)
FUNCTION
Diagnostictestmode Function
A technician canadjust somedevices
Work support
fasterandmore accurately byfollowing
indications onCONSULT.
Self-diagnostic results Self-diagnostic
resultscanberead and
erased quickly.
Data monitor
Input/Outputdatainthe ECM canberead.
CONSULT drivessomeactuators apart
Active test fromtheECM's andalso shifts some
parameters inaspecified range.
ECM partnumbers
ECMpartnumbers canberead.
Conducted byCONSULT insteadofatech-
Function test
niciantodetermine whethereachsystem
is "OK" or"NG".
WORK SUPPORT MODE
WORK ITEM
CONDITION USAGE
THRTL POSSENADJ
CHECKTHETHROTTLE POSITIONSENSORSIGNAL. Whenadjusting throttleposition
ADJUST ITTO THE SPECIFIED VALUEBYROTATING
sensorinitialposition
THE SENSOR BODYUNDER THEFOLLOWING CONDI-
TIONS .
• IGN SW"ON"
• ENG NOTRUNNING
• ACC PEDAL NOTPRESSED
IGNITION TIMINGADJ
•IGNITION TIMINGFEEDBACK CONTROLWILLBE
Whenadjusting initialignition
HELD BYTOUCHING "START".AFTERDOINGSO, timing
ADJUST IGNITION TIMINGWITHATIMING LIGHTBY
TURNING THECAMSHAFT POSITIONSENSOR.
IACV-AAC VALVEADJ
SETENGINE SPEEDATTHE SPECIFIED VALUEUNDER
Whenadjusting idlespeed
THE FOLLOWING CONDITIONS.
• ENGINE WARMED UP
• NO-LOAD
FUEL PRESSURE RELEASE •FUEL PUMP WILLSTOP BYTOUCHING "START"
Whenreleasing fuelpressure
DURING IDLING.
fromfuelline
CRANK AFEW TIMES AFTER ENGINE STALLS
EC-256

ON-BOARDDIAGNOSTIC SYSTEMDESCRIPTION
CONSULT (Cont'd)
SELF-DIAGNOSTIC MODE
Regarding itemsdetected in"SELF-DiAG RESULTS"mode,referto"Diagnostic TroubleCode(DTC)
Chart". (Seepage EC-268.)
DATA MONITOR MODE

Monitored item ECM
Main
[Unit] input
signals Description
Remarks
signals
CMPS.RPM •Indicates theengine speedcomputed •
Accuracy becomespoorifengine
(REF) [rpm] fromtheREF signal (180'signal) of speeddropsbelow theidle rpm.

0 0
the
camshaft positionsensor. •
Ifthe signal isinterrupted whilethe
engine isrunning, anabnormal value
may beindicated .
MAS AIR/FL SE[V]

0 0
•
The sig~al voltage ofthe mass air •
When theengine isstopped, acertain
flow sensor isdisplayed. valueisindicated .
COOLAN TEMP/S •
The engine coolant temperature •
When theengine coolant temperature
rOC] orrF] (determined
bythe signal voltage ofsensor
isopen orshort-circuited,

0 0
the
engine coolant temperature sen-ECMenters fail-safe mode.The
sor) isdisplayed. engine
coolant temperature deter-
mined bythe ECM isdisplayed .

02
SEN [V]

00
•
The signal voltage ofthe heated oxy-
gen sensor isdisplayed.
M/R F/CMNT •
Display ofheated oxygen sensorsig-•
After turning ONthe ignition switch,
[RICH/LEAN] nal
during air-fuel ratiofeedback con-"RICH"
isdisplayed untilair-fuel mix-
trol: ture
ratio feedback controlbegins.
RICH ...means themixture became •
When theair-fuel ratiofeedback is

0 0
"rich",
andcontrol isbeing affected clamped,
thevalue justbefore the
toward aleaner mixture. clamping
isdisplayed continuously.
LEAN ...means themixture became
"lean", andcontrol isbeing affected
toward arich mixture .
VHCL SPEED SE •
The vehicle speedcomputed fromthe
[km/h] or[mph]

00
vehicle
speedsensor signalisdis-
played .
SA TTERY VOLT[V]

0 0
•
The power supply voltage ofECM is
displayed .
THRTL POSSEN [V]

0 0
•
The throttle position sensorsignal
voltage isdisplayed.
START SIGNAL •
Indicates [ON/OFF] conditionfromthe•
After starting theengine, [OFF]isdis-
[ON/OFF]
00
starter
signal. played
regardless ofthe starter sig-
nal.
CLSD THLIPOSI •
Indicates theclosed throttle position
[ON/OFF] [ON/OFF]
determined bythe throttle

0 0
position
sensorsignal.
ON: Closed throttle position
OFF: Other thanclosed throttle
position

NOTE:

Any monitored itemthatdoes notmatch thevehicle beingdiagnosed isdeleted fromthedisplay auto-
matically.

EC-257
•