NISSAN PICK-UP 1998 Repair Manual

Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
INJ PULSE [msec]
j
lIndicates the actual fuel injection pulse
width compensated by ECM according to
the input signals.lWhen the engine is stopped, a certain
computed value is indicated.
IGN TIMING [BTDC]
j
lIndicates the ignition timing computed by
ECM according to the input signals.lWhen the engine is stopped, a certain
value is indicated.
IACV-AAC/V [%]
j
lIndicates the idle air control valve (AAC
valve) control value computed by ECM
according to the input signals.
A/F ALPHA [%]
j
lThe mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.lWhen the engine is stopped, a certain
value is indicated.
lThis data also includes the data for the
air-fuel ratio learning control.
AIR COND RLY
[ON/OFF]
j
lThe air conditioner relay control condition
(determined by ECM according to the
input signal) is indicated.
FUEL PUMP RLY
[ON/OFF]
j
lIndicates the fuel pump relay control con-
dition determined by ECM according to
the input signals.
SWRL CONT S/V
[ON/OFF]
j
lThe control condition of the swirl control
valve control solenoid valve (determined
by the ECM according to the input signal)
is indicated.
ON ... Swirl control valve is closed
OFF ... Swirl control valve is open
EGRC SOL/V
(EVAP canister purge
control solenoid
valve) [ON/OFF]
j
lThe control condition of the EVAP canis-
ter purge control solenoid valve (deter-
mined by ECM according to the input
signal) is indicated.
ON ... EVAP canister purge control is not
operating
OFF ... EVAP canister purge control is
operational.
VOLTAGE
[V]
lVoltage measured by the voltage probe.
PULSE
[msec] or [Hz] or [%]
lPulse width, frequency or duty cycle
measured by the pulse probe.lOnly ``#'' is displayed if item is unable to
be measured.
lFigures with ``#''s are temporary ones.
They are the same figures as an actual
piece of data which was just previously
measured.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-49

ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTION
lEngine: Return to the original trouble
condition
lChange the amount of fuel injection
using CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lHarness and connectorlFuel injectorslHeated oxygen sensor
IACV-AAC/V
OPENING
lEngine: After warming up, idle the
engine.
lChange the IACV-AAC valve opening
percent using CONSULT.Engine speed changes according to the
opening percent.lHarness and connectorlIACV-AAC valve
ENG COOLANT
TEMP
lEngine: Return to the original trouble
condition
lChange the engine coolant
temperature using CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lHarness and connectorlEngine coolant temperature sensorlFuel injectors
IGNITION TIMING
lEngine: Return to the original trouble
condition
lTiming light: SetlRetard the ignition timing using
CONSULT.If trouble symptom disappears, see
CHECK ITEM.
lAdjust ignition timing (by moving
camshaft position sensor)
POWER BALANCE
lEngine: After warming up, idle the
engine.
lA/C switch ``OFF''lShift lever ``N''lCut off each injector signal one at a
time using CONSULT.Engine runs rough or dies.
lHarness and connectorlCompressionlInjectorslIgnition coil with power transistorlSpark plugs
FUEL PUMP RELAY
lIgnition switch: ON (Engine stopped)lTurn the fuel pump relay ``ON'' and
``OFF'' using CONSULT and listen to
operating sound.Fuel pump relay makes the operating
sound.lHarness and connectorlFuel pump relay
EGRC SOLENOID
VALVE
(EVAP canister
purge control
solenoid valve)
lIgnition switch: ONlTurn solenoid valve ``ON'' and ``OFF''
with CONSULT and listen to
operating sound.Solenoid valve makes an operating
sound.lHarness and connectorlEVAP canister purge control solenoid
valve
SWIRL CONT SOL
VALVE
lIgnition switch: ON (Engine stopped)lTurn solenoid valve ``ON'' and ``OFF''
with CONSULT and listen to
operating sound.Solenoid valve makes an operating
sound.lHarness and connectorlSwirl control valve control solenoid
valve
SELF-LEARNING
CONT
lIn this test, the coefficient of self-learning control mixture ratio returns to the original coefficient by touching ``CLEAR'' on the
screen.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-50

FUNCTION TEST MODE
FUNCTION TEST
ITEMCONDITION JUDGEMENT CHECK ITEM (REMEDY)
SELF-DIAG
RESULTS
lIgnition switch: ON
(Engine stopped)
lDisplays the results of on board
diagnostic system.Ð Objective system
CLOSED THROTTLE
POSI
lIgnition switch: ON
(Engine stopped)
lThrottle position sensor circuit is
tested when throttle is opened
and closed fully. (``IDLE
POSITION'' is the test item name
for the vehicles in which idle is
selected by throttle position
sensor.)Throttle valve:
openedOFF
lHarness and connector
lThrottle position sensor (Closed
throttle position)
lThrottle position sensor (Closed
throttle position) adjustment
lThrottle linkage
lVerify operation in DATA
MONITOR mode. Throttle valve:
closedON
THROTTLE POSI
SEN CKT
lIgnition switch: ON
(Engine stopped)
lThrottle position sensor circuit is
tested when throttle is opened
and closed fully.Range (Throttle
valve fully opened
Ð Throttle valve
fully closed)More than
3.0V
lHarness and connector
lThrottle position sensor
lThrottle position sensor
adjustment
lThrottle linkage
lVerify operation in DATA
MONITOR mode.
PARK/NEUT POSI
SW CKT
lIgnition switch: ON
(Engine stopped)
lNeutral position switch circuit is
tested when shift lever is
manipulated.Out of N/P
positionsOFF
lHarness and connector
lNeutral position switch
lLinkage adjustment
In N/P positions ON
FUEL PUMP
CIRCUIT
lIgnition switch: ON
(Engine stopped)
lFuel pump circuit is tested by
checking the pulsation in fuel
pressure when fuel tube is
pinched.There is pressure pulsation on
the fuel feed hose.
lHarness and connector
lFuel pump
lFuel pump relay
lFuel filter clogging
lFuel level
EGRC SOL/V
CIRCUIT
(EVAP canister purge
control solenoid valve
circuit)
lIgnition switch: ON
(Engine stopped)
lEVAP canister purge control
solenoid valve circuit is tested by
checking solenoid valve operating
noise.The solenoid valve makes an
operating sound every 3
seconds.lHarness and connector
lEVAP canister purge control
solenoid valve
START SIGNAL
CIRCUIT
lIgnition switch: ON®START
lStart signal circuit is tested when
engine is started by operating the
starter. Battery voltage and water
temperature before cranking, and
average battery voltage, mass air
flow sensor output voltage and
cranking speed during cranking
are displayed.Start signal: OFF®ON
lHarness and connector
lIgnition switch
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-51

FUNCTION TEST
ITEMCONDITION JUDGEMENT CHECK ITEM (REMEDY)
PW/ST SIGNAL
CIRCUIT
lIgnition switch: ON
(Engine running)
lPower steering oil pressure switch
circuit is tested when steering
wheel is rotated fully and then set
to a straight line running position.Locked position ONlHarness and connector
lPower steering oil pressure switch
lPower steering oil pump
Neutral position OFF
SWRL CONT S/V
CIRCUIT
lIgnition switch: ON
(Engine stopped)
lSwirl control valve control sole-
noid valve circuit is tested by
checking solenoid valve operating
sound.The solenoid valve makes an
operating sound every 3 sec-
onds.
lHarness and connector
lSolenoid valve
lSwirl control valve
lVacuum hose
VEHICLE SPEED
SEN CKT
lVehicle speed sensor circuit is
tested when vehicle is running at
a speed of 10 km/h (6 MPH) or
higher.Vehicle speed sensor input
signal is greater than 4 km/h
(2 MPH).lHarness and connector
lVehicle speed sensor
lSpeedometer
IGN TIMING ADJ
lAfter warming up, idle the engine.
lIgnition timing is checked by read-
ing ignition timing with a timing
light and checking whether it
agrees with specifications.The timing light indicates the
same value on the screen.
lAdjust ignition timing (by moving
camshaft position sensor or
distributor)
lCamshaft position sensor drive
mechanism
MIXTURE RATIO
TEST
lAir-fuel ratio feedback circuit
(injection system, ignition system,
vacuum system, etc.) is tested by
examining the heated oxygen
sensor output at 2,000 rpm under
non-loaded state.Heated oxygen sensor
COUNT: More than 5 times
during 10 seconds
lINJECTION SYS (Injector, fuel
pressure regulator, harness or
connector)
lIGNITION SYS (Spark plug,
ignition coil, power transistor
harness or connector)
lVACUUM SYS (Intake air leaks)
lHeated oxygen sensor circuit
lHeated oxygen sensor operation
lFuel pressure high or low
lMass air flow sensor
POWER BALANCE
lAfter warming up, idle the engine.
lInjector operation of each cylinder
is stopped one after another, and
resultant change in engine rota-
tion is examined to evaluate com-
bustion of each cylinder. (This is
only displayed for models where a
sequential multiport fuel injection
system is used.)Difference in engine speed is
greater than 25 rpm before
and after cutting off the injec-
tor of each cylinder.lInjector circuit (Injector, harness
or connector)
lIgnition circuit (Spark plug, igni-
tion coil, power transistor harness
or connector)
lCompression
lValve timing
IACV-AAC/V
SYSTEM
lAfter warming up, idle the engine.
lIACV-AAC valve system is tested
by detecting change in engine
speed when IACV-AAC valve
opening is changed to 0%, 20%
and 80%.Difference in engine speed is
greater than 150 rpm between
when valve opening is at 80%
and at 20%.
lHarness and connector
lIACV-AAC valve
lAir passage restriction between
air inlet and IACV-AAC valve
lIAS (Idle adjusting screw) adjust-
ment
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-52

REAL TIME DIAGNOSIS IN DATA MONITOR MODE
CONSULT has two kinds of triggers and they can be selected by touching ``SETTING'' in ``DATA MONITOR''
mode.
1. ``AUTO TRIG'' (Automatic trigger):
lThe malfunction will be identified on the CONSULT screen in real time.
In other words, malfunction item will be displayed at the moment the malfunction is detected by ECM.
DATA MONITOR can be performed continuously until a malfunction is detected. However, DATA
MONITOR cannot continue any longer after the malfunction detection.
2. ``MANU TRIG'' (Manual trigger):
lMalfunction item will not be displayed automatically on CONSULT screen even though a malfunc-
tion is detected by ECM.
DATA MONITOR can be performed continuously even though a malfunction is detected.
Use these triggers as follows:
1. ``AUTO TRIG''
lWhile trying to detect the DTC by performing the ``DTC CONFIRMATION PROCEDURE'', be sure to
select to ``DATA MONITOR (AUTO TRIG)'' mode. You can confirm the malfunction at the moment
it is detected.
lWhile narrowing down the possible causes, CONSULT should be set in ``DATA MONITOR (AUTO
TRIG)'' mode, especially in case the incident is intermittent.
When you are inspecting the circuit by gently shaking (or twisting) the suspicious connectors, com-
ponents and harness in the ``DTC CONFIRMATION PROCEDURE'', the moment a malfunction is
found the malfunction item will be displayed. (Refer to GI section, ``Incident Simulation Tests'' in
``HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT''.)
2. ``MANU TRIG''
lIf the malfunction is displayed as soon as ``DATA MONITOR'' is selected, reset CONSULT to ``MANU
TRIG''. By selecting ``MANU TRIG'' you can monitor and store the data. The data can be utilized for
further diagnosis, such as a comparison with the value for the normal operating condition.
SEF529Q
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
CONSULT (Cont'd)
EC-53

Introduction
The engine has an ECM to control major systems such as fuel
control, ignition control, idle air control system, etc. The ECM
accepts input signals from sensors and instantly drives actua-
tors. It is essential that both input and output signals are proper
and stable. At the same time, it is important that there are no
problems such as vacuum leaks, fouled spark plugs, or other
problems with the engine.
It is much more difficult to diagnose a problem that occurs inter-
mittently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A
road test with CONSULT or a circuit tester connected should be
performed. Follow the ``Work Flow'' on EC-56.
Before undertaking actual checks, take just a few minutes to talk
with a customer who approaches with a driveability complaint.
The customer can supply good information about such problems,
especially intermittent ones. Find out what symptoms are present
and under what conditions they occur. A ``Diagnostic Worksheet''
like the example on next page should be used.
Start your diagnosis by looking for ``conventional'' problems first.
This will help troubleshoot driveability problems on an electroni-
cally controlled engine vehicle.
Diagnostic Worksheet
There are many operating conditions that lead to the malfunc-
tions of engine components. A good knowledge of such condi-
tions can make troubleshooting faster and more accurate.
In general, each customer may feel differently about a given
problem. It is important to fully understand the symptoms or
conditions for a customer complaint.
Utilize a diagnostic worksheet like the one on next page in order
to organize all the information for troubleshooting.
MEF036D
SEF233G
SEF234G
SEF907L
TROUBLE DIAGNOSIS Ð IntroductionKA
EC-54

WORKSHEET SAMPLE
Customer name MR/MS Model & Year VIN
Engine # Trans. Mileage
Incident Date Manuf. Date In Service Date
Fuel and fuel filler caphVehicle ran out of fuel causing misfire.
hFuel filler cap was left off or incorrectly screwed on.
SymptomshStartabilityhImpossible to starthNo combustionhPartial combustion
hPartial combustion affected by throttle position
hPartial combustion NOT affected by throttle position
hPossible but hard to starthOthers [ ]
hIdlinghNo fast idlehUnstablehHigh idlehLow idle
hOthers [ ]
hDriveabilityhStumblehSurgehKnockhLack of power
hIntake backfirehExhaust backfire
hOthers [ ]
hEngine stallhAt the time of starthWhile idling
hWhile acceleratinghWhile decelerating
hJust after stoppinghWhile loading
Incident occurrencehJust after deliveryhRecently
hIn the morninghAt nighthIn the daytime
FrequencyhAll the timehUnder certain conditionshSometimes
Weather conditionshNot affected
WeatherhFinehRaininghSnowinghOthers [ ]
TemperaturehHothWarmhCoolhColdhHumid ÉF
Engine conditionshColdhDuring warm-uphAfter warm-up
Engine speed
Road conditionshIn townhIn suburbshHighwayhOff road (up/down)
Driving conditionshNot affected
hAt startinghWhile idlinghAt racing
hWhile acceleratinghWhile cruising
hWhile deceleratinghWhile turning (RH/LH)
Vehicle speed
Malfunction indicator lamphTurned onhNot turned on
TROUBLE DIAGNOSIS Ð IntroductionKA
Diagnostic Worksheet (Cont'd)
EC-55

Work Flow
CHECK IN
CHECK INCIDENT CONDITIONS.
Listen to customer complaints. (Get symptoms.)..........................
STEP I
CHECK DTC.
Check and print out (write down) Diagnostic Trouble Code (DTC). Then clear.
If DTC is not available even if MIL lights up, check ECM fail-safe. (Refer to EC-61.)
Also check related service bulletins for information.
....................
STEP II
Symptoms collected No symptoms, except MIL
lights up, or
DTC exists at STEP II.
Verify the symptom by driving in the condition the customer
described.
.
*1
............................................................................
STEP III
Normal Code
(at STEP II)
Malfunction Code
(at STEP II)
INCIDENT INFORMATION
Verify the DTC by performing the ``DTC CONFIRMATION PROCEDURE''.
*1
....................
STEP IV
cChoose the appropriate action.
Malfunction Code (at STEP II or IV) Normal Code (at both STEP II and IV)....................
*2STEP V
BASIC INSPECTION
SYMPTOM BASIS (at STEP I or III)
............................................................c
Perform inspections according
to Symptom Matrix Chart.
.
TROUBLE DIAGNOSIS FOR DTC XX.STEP VI
REPAIR/REPLACE
NGFINAL CHECK
Confirm that the incident is completely fixed by performing BASIC INSPECTION and DTC CON-
FIRMATION PROCEDURE (or OVERALL FUNCTION CHECK).
Then, erase the unnecessary (already fixed) DTCs in ECM.
OK....................
STEP VII
CHECK OUT
*1: If the incident cannot be duplicated, see ``Incident Simulation Tests'' of ``HOW TO PERFORM EFFICIENT DIAGNO-
SIS FOR AN ELECTRICAL INCIDENT'' in GI section.
*2: If the on board diagnostic system cannot be performed, check main power supply and ground circuit (See TROUBLE
DIAGNOSIS FOR POWER SUPPLY, EC-75).
.
.
.
.
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS Ð Work FlowKA
EC-56

Description for Work Flow
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using the
``DIAGNOSTIC WORK SHEET'', EC-54.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT) the Diagnostic Trouble Code
(DTC), then erase the code. (Refer to EC-36.) The DTC can be used when duplicating the incident at STEP III &
IV.
Study the relationship between the cause, specified by DTC, and the symptom described by the customer. (The
``Symptom Matrix Chart'' will be useful. See page EC-62.)
Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The ``DIAGNOSTIC WORK SHEET'' is useful to verify the incident. Connect CONSULT to the vehicle in DATA
MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform INCIDENT SIMULATION TESTS. (Refer to GI section.)
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the Diagnostic Trouble Code by driving in (or performing) the ``DTC CONFIRMATION PROCEDURE''.
Check and read the DTC by using CONSULT.
During the DTC verification, be sure to connect CONSULT to the vehicle in DATA MONITOR (AUTO TRIG) mode
and check real time diagnosis results.
If the incident cannot be verified, perform INCIDENT SIMULATION TESTS. (Refer to GI section.)
In case the ``DTC CONFIRMATION PROCEDURE'' is not available, perform the ``OVERALL FUNCTION CHECK''
instead. The DTC cannot be displayed by this check, however, this simplified ``check'' is an effective alternative.
The ``NG'' result of the ``OVERALL FUNCTION CHECK'' is the same as the DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to TROUBLE DIAGNOSIS FOR DTC XX.
If the normal code is indicated, proceed to the BASIC INSPECTION on next page. Then perform inspections
according to the Symptom Matrix Chart. (Refer to EC-62.)
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes. Inspect
the system for mechanical binding, loose connectors or wiring damage using (tracing) ``Harness Layouts''.
Gently shake the related connectors, components or wiring harness with CONSULT set in ``DATA MONITOR
(AUTO TRIG)'' mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CON-
SULT. Refer to EC-64, EC-68.
The ``DIAGNOSTIC PROCEDURE'' in EC section contains a description based on open circuit inspection. A short
circuit inspection is also required for the circuit check in the DIAGNOSTIC PROCEDURE. For details, refer to GI
section (``HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT'', ``Circuit Inspection'').
Repair or replace the malfunction parts.
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions
and circumstances which resulted in the customer's initial complaint.
Perform the ``DTC CONFIRMATION PROCEDURE'' and confirm the normal code (Diagnostic trouble code No. 55)
is detected. If the incident is still detected in the final check, perform STEP VI by using a different method from the
previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) DTC in ECM. (Refer
to EC-36.)
TROUBLE DIAGNOSIS Ð Work FlowKA
EC-57

Basic Inspection
Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
lHeadlamp switch is OFF,
lAir conditioner switch is OFF,
lRear window defogger switch is OFF,
lSteering wheel is in the straight-ahead position, etc.
BEFORE STARTING
1. Check service records for any recent
repairs that may indicate a related
problem, or the current need for sched-
uled maintenance.
2. Open engine hood and check the fol-
lowing:
lHarness connectors for improper con-
nections
lVacuum hoses for splits, kinks, or
improper connections
lWiring for improper connections,
pinches, or cuts
CONNECT CONSULT TO THE
VEHICLE.
Connect ``CONSULT'' to the data link
connector for CONSULT and select
``ENGINE'' from the menu. Refer to
EC-45.
CHECK IGNITION TIMING.
1. Warm up engine sufficiently.
2. Select ``IGN TIMING ADJ'' in
``WORK SUPPORT'' mode.
3. Touch ``START''.
4. Check ignition timing at idle
using timing light.
Ignition timing:
10É 2É BTDC
----------------------------------------------------------------------------------------------------------------------------------OR----------------------------------------------------------------------------------------------------------------------------------
1. Warm up engine sufficiently.
2. Stop engine and disconnect
throttle position sensor sub-
harness connector.
3. Start engine.
4. Check ignition timing at idle
using timing light.
Ignition timing:
10É 2É BTDC
OK
cNG
Adjust ignition timing by
turning camshaft position
sensor.
VA
(Go to next page.)
SEF142I
SEF056UA
SEF555N
SEF148U
SEF284G
.
.
.
TROUBLE DIAGNOSIS Ð Basic InspectionKA
EC-58