1998 NISSAN PATROL Engine Control Workshop Manual

Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
AIR COND SIG
[ON/OFF]
jj
+Indicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
IGN SW
[ON/OFF]
jj+Indicates [ON/OFF] condition from igni-
tion switch signal.
MAS AIR/FL SE [V]
jj+The signal voltage of the mass air ¯ow
sensor is displayed.+When the engine is stopped, a certain
value is indicated.
ACT INJ TIMG [É]
jj
+The actual injection timing angle deter-
mined by the ECM (an approximate
average angle between injection start
and end from TDC) is displayed.
INJ TIMG C/V [%]+Indicates the duty ratio of fuel injection
timing control valve.
DECELER F/CUT
[ON/OFF]
j
+Indicates [ON/OFF] condition from decel-
eration fuel cut signal.+When the accelerator pedal is released
quickly with engine speed at 3,000 rpm
or more, ``ON'' is displayed.
FUEL CUT S/V
[ON/OFF]
j
+The control condition of the fuel cut sole-
noid valve (determined by ECM accord-
ing to the input signal) is indicted.
+OFF ... Fuel cut solenoid valve is not
operating.
ON ... Fuel cut solenoid valve is operat-
ing.+When the fuel cut solenoid valve is not
operating, fuel is not supplied to injection
nozzles.
GLOW RLY [ON/OFF]
j
+The glow relay control condition (deter-
mined by ECM according to the input
signal) is displayed.
COOLING FAN
[LOW/HI/OFF]
j
+Indicates the control condition of the
cooling fans (determined by ECM
according to the input signal).
+LOW ... Operates at low speed.
HI ... Operates at high speed.
OFF ... Stopped.
I/C FAN RLY
[ON/OFF]
j
+Indicates the control condition of the
charge air cooler fan (determined by
ECM according to the input signals).
EGRC SOL/V A
[ON/OFF]+The control condition of the EGRC-sole-
noid valve A (determined by ECM
according to the input signal) is indi-
cated.
+OFF ... EGRC-solenoid valve A is not
operating.
ON ... EGRC-solenoid valve A is operat-
ing.
EGRC SOL/V B
[ON/OFF]+The control condition of the EGRC-sole-
noid valve B (determined by ECM
according to the input signal) is indi-
cated.
+OFF ... EGRC-solenoid valve B is not
operating.
ON ... EGRC-solenoid valve B is operat-
ing.
THROT RLY
[ON/OFF]+The control condition of the throttle con-
trol solenoid valve (determined by ECM
according to the input signal) is indi-
cated.
+OFF ... Throttle control solenoid valve is
not operating.
ON ... Throttle control solenoid valve is
operating.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT (Cont'd)
EC-39

ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
COOLING FAN+Ignition switch: ON
+Operate the cooling fan at
``LOW'', ``HI'' speed and turn
``OFF'' using CONSULT.Cooling fan moves at ``LOW'', ``HI''
speed and stops.+Harness and connector
+Cooling fan motor
OFF ACCEL PO
SIG+Clears the self-learning fully closed accelerator position, detected by accelerator position sensor, from the
ECM.
FUEL CUT SOL/V+Ignition switch: ON
+Turn solenoid valve ``ON'' and
``OFF'' with the CONSULT and
listen to operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
EGRC SOL/V A+Ignition switch: ON
+Turn solenoid valve ``ON'' and
``OFF'' with the CONSULT and
listen to operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
EGRC SOL/V B+Ignition switch: ON
+Turn solenoid valve ``ON'' and
``OFF'' with the CONSULT and
listen to operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
THROT CONT
SOL/V+Ignition switch: ON
+Turn solenoid valve ``ON'' and
``OFF'' with the CONSULT and
listen to operating sound.Solenoid valve makes an operating
sound.+Harness and connector
+Solenoid valve
GLOW RLY+Ignition switch: ON (Engine
stopped)
+Turn the glow relay ``ON'' and
``OFF'' using CONSULT and
listen to operating sound.Glow relay makes the operating
sound.+Harness and connector
+Glow relay
INJ TIMING+Engine: Return to the original
trouble condition
+Retard the injection timing using
CONSULT.If trouble symptom disappears, see
CHECK ITEM.+Adjust initial injection timing
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT (Cont'd)
EC-40

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):
+The malfunction will be identi®ed on the CONSULT screen in real time.
In other words, the 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):
+The malfunction 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''
+While trying to detect the DTC by performing the ``DTC CONFIRMATION PROCEDURE'', be sure to
select to ``DATA MONITOR (AUTO TRIG)'' mode. You can con®rm the malfunction at the moment it is
detected.
+While narrowing down the possible causes, CONSULT should be set in ``DATA MONITOR (AUTO
TRIG)'' mode, especially in case the incident is intermittent.
Inspect the circuit by gently shaking (or twisting) suspicious connectors, components 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''
+If 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 DESCRIPTION
CONSULT (Cont'd)
EC-41

Introduction
The engine has an ECM to control major systems such as fuel
injection control, fuel injection timing control, glow control system,
etc. The ECM accepts input signals from sensors and instantly
drives electronic fuel injection pump. 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, or
other problems with the engine.
It is much more difficult to diagnose a problem that occurs intermit-
tently 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 ®nd the cause of the problems. A road
test with CONSULT or a circuit tester connected should be per-
formed. Follow the ``Work Flow'', EC-44.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The cus-
tomer 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 ®rst.
This will help troubleshoot driveability problems on an electronically
controlled engine vehicle.
SEF858S
SEF233G
SEF234G
TROUBLE DIAGNOSIS Ð Introduction
EC-42

Diagnostic Worksheet
There are many operating conditions that lead to the malfunction
of engine components. A good grasp of such conditions can make
troubleshooting faster and more accurate.
In general, each customer feels differently about a problem. It is
important to fully understand the symptoms or conditions for a
customer complaint.
Utilize a diagnostic worksheet like the one shown below in order to
organize all the information for troubleshooting.
WORKSHEET SAMPLE
Customer name MR/MS Model & Year VIN
Engine # Trans. Mileage
Incident Date Manuf. Date In Service Date
SymptomshStartabilityhImpossible to starthNo combustionhPartial combustion
hPartial combustion when engine is warm
hPartial combustion when engine is cool
hPossible but hard to starthOthers [ ]
hIdlinghNo fast idlehUnstablehHigh idlehLow idle
hOthers [ ]
hDriveabilityhStumblehSurgehKnockhLack of power
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
SEF907L
TROUBLE DIAGNOSIS Ð Introduction
EC-43

Work Flow
CHECK IN
CHECK INCIDENT CONDITIONS.
Listen to customer complaints. (Get symptoms.).................................................
STEP I
Check andPRINT OUT(write down) Diagnostic Trouble Code (DTC).
Then clear. Also check related service bulletins for information.
...........................................
STEP II
Symptoms
collected.No symptoms, except MIL
lights up, or Malfunction
Code exists at STEP II.
Verify the symptom by driving in the condition the cus-
tomer described.
.
*1
.............................................................................................
STEP III
Normal Code
(at STEP II)
Malfunction Code
(at STEP II)
INCIDENT CONFIRMATION
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
Con®rm that the incident is completely ®xed by performing BASIC INSPECTION and
DTC CONFIRMATION PROCEDURE (or OVERALL FUNCTION CHECK). Then,
erase the unnecessary (already ®xed) DTCs in ECM.
OK...........................................
STEP VII
CHECK OUT
*1: If the incident cannot be duplicated, refer to GI section (``Incident Simulation Tests'', ``HOW TO PERFORM EFFICIENT
DIAGNOSIS FOR AN ELECTRICAL INCIDENT'').
*2: If the on board diagnostic system cannot be performed, check main power supply and ground circuit. Refer to
``TROUBLE DIAGNOSIS FOR POWER SUPPLY'', EC-63.
.
.
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.
.
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TROUBLE DIAGNOSIS Ð Work Flow
EC-44

Description for Work Flow
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using the
``DIAGNOSTIC WORKSHEET'' as shown on EC-43.
STEP IIBefore con®rming the concern, check and write down (print out using CONSULT) the Diagnostic Trouble Code
(DTC), then erase the code. Refer to EC-30.
Study the relationship between the cause, speci®ed by DTC, and the symptom described by the customer. (The
``Symptom Matrix Chart'' will be useful. Refer to EC-48.)
STEP IIITry to con®rm 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 veri®ed, 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 (DTC) by driving in (or performing) the ``DTC CONFIRMATION PROCE-
DURE''. Check and read the DTC by using CONSULT.
During the DTC veri®cation, 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 veri®ed, 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 simpli®ed ``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. Refer to EC-46. Then perform inspections
according to the Symptom Matrix Chart. Refer to EC-48.
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-54.
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 (``Circuit Inspection'', ``HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT'').
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 con®rm the normal code (Diagnostic trouble code No. 55)
is detected. If the incident is still detected in the ®nal 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 ®xed) DTC in ECM. (Refer
to EC-30.)
TROUBLE DIAGNOSIS Ð Work Flow
EC-45

Basic Inspection
Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
+Headlamp switch is OFF,
+Air conditioner switch is OFF,
+Rear defogger switch is OFF,
+Steering 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:
+Harness connectors for improper con-
nections
+Vacuum hoses for splits, kinks, or
improper connections
+Wiring for improper connections,
pinches, or cuts
3. Using priming pump, bleed air from fuel
system. Refer to ``DRAINING WATER'',
``Checking and Replacing Fuel Filter
and Draining Water'' of ``ENGINE
MAINTENANCE'' in MA section.
CONNECT CONSULT TO THE VEHICLE.
Connect ``CONSULT'' to the data link con-
nector for CONSULT and select
``ENGINE'' from the menu. Refer to
EC-36.
DOES ENGINE START?
Ye s
cNo
Turn ignition switch OFF,
wait 5 seconds and then
start engine. If engine fails
to start, check diagnostic
trouble code (DTC).
Run engine for 10 minutes.
CHECK IDLE SPEED.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Read engine idle speed in ``DATA
MONITOR'' mode with CONSULT.
--------------------------------------------------------------------------------------------------------------------------------------OR--------------------------------------------------------------------------------------------------------------------------------------
Check idle speed using tachom-
eter tester.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
775 25 rpm
(Go tojAon next page.)
SEF142I
SEF670V
SEF669V
SEF714V
SEF671V
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TROUBLE DIAGNOSIS Ð Basic Inspection
EC-46