1998 NISSAN PICK-UP Repair Manual

VAVB
b
Adjust ignition timing to the specified value by turning dis-
tributor after loosening bolts which secure distributor.
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10É 2É BTDC
Check base idle speed.
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Read idle speed in ``IGN TIMING ADJ'' mode
with CONSULT.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Check idle speed.
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750 25 rpm
OKNG
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no-
load and run engine at idle speed.
Adjust base idle speed by turning idle speed adjusting
screw.
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750 25 rpm
c
Touch ``Back''.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1. Stop engine and connect throttle position sen-
sor harness connector.
2. Start engine.
Rev engine (2,000 - 3,000 rpm) 2 or 3 times under no-
load and run engine at idle speed.
VC
SMA189AA
SEF546N
SEF147U
SEF913J
SEF602K
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BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-33

VC
Check target idle speed.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Read idle speed in ``DATA MONI-
TOR'' mode with CONSULT.
-----------------------------------------------------------------------------------------------------------------------------------------------OR-----------------------------------------------------------------------------------------------------------------------------------------------
Check idle speed.
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800 50 rpm
OKNG
Check IACV-AAC valve and replace if neces-
sary.
Check IACV-AAC valve harness and repair if
necessary.
Check ECM function* by substituting another
known good ECM.
VD
* ECM may be the cause of
a problem, but this is rarely
the case.
.
INSPECTION END
SEF051U
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BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-34

Checking and adjusting mixture ratio
INSPECTION START
Check and adjust idle speed and ignition timing.
(Refer to EC-32.)
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Idle speed: 800 50 rpm
Ignition timing: 10É 2É BTDC
Rev engine (2,000 - 3,000 rpm) 2 or 3 times
under no-load, then run engine at idle speed.
Check ``CO''% with ``CO''-meter.
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Idle ``CO''%
Below 2.0
NGOK
Remove seal label which seals ECM variable
resistor.
Adjust ``CO''% by turning variable resistor on
ECM.
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Idle ``CO''%
1.5 0.5
Install a new seal label on ECM variable resistor.
Rev engine (2,000 - 3,000 rpm) 2 or 3 times
under no-load, then run engine at idle speed.
Check idle speed.
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Idle speed: 800 50 rpm
OK
cNGAdjust idle speed.
(See page EC-32.)
Stop engine.b
b
INSPECTION END
SEF602K
SEF494S
SEF495S
.
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BASIC SERVICE PROCEDUREKA
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment (Cont'd)
EC-35

Introduction
The ECM (ECCS control module) has an on board diagnostic system, which detects malfunctions related to
engine sensors or actuators. Self-diagnosis items are listed in ``DIAGNOSTIC TROUBLE CODE INDEX'',
EC-1.
The malfunction indicator lamp (MIL) on the instrument panel lights up when a malfunction is detected, or
when the ECM enters fail-safe mode (Refer to EC-61).
Diagnostic Trouble Code (DTC)
HOW TO CONFIRM MALFUNCTION ITEMS
Malfunction items can be confirmed by the following methods.
1. The number of blinks of the malfunction indicator lamp in the Diagnostic Test Mode II (Self- Diag-
nostic Results) indicates the DTC. Examples: 11, 21 etc.
2. CONSULT displays the malfunctioning component or system in ``SELF DIAGNOSTIC RESULTS''
mode.
lOutput of a DTC indicates a malfunction. However, Mode II does not indicate whether the mal-
function is still occurring or has occurred in the past and has returned to normal.
CONSULT can identify malfunction status as shown below. Therefore, using CONSULT (if avail-
able) is recommended.
A sample of CONSULT display is shown at left. The malfunction
is displayed in SELF-DIAGNOSTIC RESULTS mode of CON-
SULT. Time data indicates how many times the vehicle was
driven after the last detection of a malfunction.
If the malfunction is being detected currently, the time data will
be ``0''.
HOW TO ERASE DTC
The DTC can be erased from the back-up memory in the ECM by the following methods.
Selecting ``ERASE'' in the SELF- DIAG RESULTS'' mode with CONSULT
Changing the diagnostic test mode from Diagnostic Test Mode II to Mode I by turning the mode
selector on the ECM (RHD model only) or connecting the data link connector for CONSULT terminals.
(Refer to EC-39, 41)
lIf the battery terminal is disconnected, the DTC will be lost within 24 hours.
lErasing the DTC, using CONSULT is easier and quicker than switching the mode selector on the
ECM (RHD model only) or connecting the data link connector for CONSULT terminals.
SEF854T
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
EC-36

How to erase DTC (With CONSULT)
1. If the ignition switch stays ``ON'' after repair work, be sure to turn ignition switch ``OFF'' once. Wait at
least 5 seconds and then turn it ``ON'' (engine stopped) again.
2. Turn CONSULT ``ON'' and touch ``ENGINE''.
3. Touch ``SELF-DIAG RESULTS''.
4. Touch ``ERASE''. (The DTC in the ECM will be erased.)
How to erase DTC (Without CONSULT)
1. If the ignition switch stays ``ON'' after repair work, be sure to turn ignition switch ``OFF'' once. Wait at
least 5 seconds and then turn it ``ON'' again.
2. Change the diagnostic test mode from Mode II to Mode I by turning the mode selector on the ECM (RHD
model only) or connecting the data link connector for CONSULT terminals. (See EC-39, 41)
SEF054U
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
Diagnostic Trouble Code (DTC) (Cont'd)
EC-37

Malfunction Indicator Lamp (MIL)
The malfunction indicator lamp is located on the instrument
panel.
1. The malfunction indicator lamp will light up when the ignition
switch is turned ON without the engine running. This is for
checking the blown lamp.
lIf the malfunction indicator lamp does not light up, see the
WARNING LAMPS AND CHIME in the EL section.
(Or see EC-173, 174.)
2. When the engine is started, the malfunction indicator lamp
should go off.
If the lamp remains on, the on board diagnostic system has
detected an engine system malfunction.
ON BOARD DIAGNOSTIC SYSTEM FUNCTION
The on board diagnostic system has the following four functions.
Diagnostic Test Mode I
1. BULB CHECK : This function checks the bulb for damage (blown, open circuit, etc.) of
the malfunction indicator lamp.
If the MIL does not come on, check MIL circuit and ECM test mode
selector. (See next page.)
2. MALFUNCTION
WARNING: This is a usual driving condition. When a malfunction is detected, the
MIL will light up to inform the driver that a malfunction has been
detected.
Diagnostic Test Mode II
3. SELF-DIAGNOSTIC
RESULTS: This function allows DTCs to be read.
4. HEATED OXYGEN
SENSOR MONITOR: This function allows the fuel mixture condition (lean or rich), monitored
by heated oxygen sensor, to be read.
MIL Flashing without DTC
If the ECM is in Diagnostic Test Mode II, the MIL may flash when the engine is running. In this case, check
ECM test mode selector following ``HOW TO SWITCH DIAGNOSTIC TEST MODES'' on next page.
How to switch the diagnostic test (function) modes and details of the above functions are described later.
(See page EC-39, 41.)
ConditionDiagnostic
Test Mode IDiagnostic
Test Mode II
Ignition switch
in ``ON'' posi-
tion
Engine
stopped
BULB CHECKSELF-DIAGNOSTIC
RESULTS
Engine
running
MALFUNCTION
WARNINGHEATED OXYGEN
SENSOR MONI-
TOR
SEF055U
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
EC-38

HOW TO SWITCH DIAGNOSTIC TEST MODES (LHD models)
Turn ignition switch ``ON''.
(Do not start engine.)
c
Diagnostic Test Mode I Ð BULB
CHECK. Refer to previous page.
MIL should come on.
OK
cNGCheck MIL circuit.
(See EC-173.)
OK
cNG
Repair harness or
connectors.
b
cG
Start engine.
cDiagnostic Test
Mode I
Ð MALFUNC-
TION WARN-
ING.
Refer to previ-
ous page.
Data link connector for CONSULT
(Connect CHK and IGN terminals with a
suitable harness.)
MIL should go off.
OK
cNG
Check MIL circuit and data link connector for
CONSULT circuit. (See EC-173.)
OK NG
Check ECM fail-
safe.
(See EC-61.)
Repair harness or
connectors.
OK
Wait at least 2 seconds.
b
Data link connector for CONSULT
(Disconnect the suitable harness
between CHK and IGN terminals.)
DIAGNOSTIC TEST MODE II
Ð SELF-DIAGNOSTIC RESULTScG
Start engine.
cDiagnostic Test
Mode II
Ð HEATED
OXYGEN
SENSOR
MONITOR
VBVA
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..
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
Malfunction Indicator Lamp (MIL) (Cont'd)
EC-39

VBmVA
.
Data link connector for CONSULT
(Connect CHK and IGN terminals with a
suitable harness.)
Wait at least 2 seconds.
*1
Data link connector for CONSULT
(Disconnect the suitable harness
between CHK and IGN terminals.)
lSwitching the modes is not possible when the
engine is running.
lWhen ignition switch is turned OFF during
diagnosis, power to ECM will drop after
approx. 5 seconds.
The diagnosis will automatically return to
Diagnostic Test Mode I.
*1: If the suitable harness is disconnected at this time, the
diagnostic trouble code will be erased from the backup
memory in the ECM..
.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONKA
Malfunction Indicator Lamp (MIL) (Cont'd)
EC-40