1998 NISSAN PICK-UP Repair Manual

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK OVERALL FUNCTION.
1. Start engine.
2. Check voltage between ECM terminal
114and ground with CONSULT or
tester under the following conditions.
Voltage:
Engine speed is below 3,200 rpm
Approximately 0V
Engine speed is above 3,200 rpm
Battery voltage
NG
cOK
INSPECTION END
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect heated oxygen sensor har-
ness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V3
and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
lHarness connectorsE101,M5
l10A fuse
lHarness for open or
short between heated
oxygen sensor and fuse
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector.
3. Check harness continuity between ter-
minal
V1and ECM terminal114.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
lHarness connectorsM5,E101
lHarness for open or
short between heated
oxygen sensor and ECM
If NG, repair open circuit,
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Heated oxygen sensor heater).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace heated oxygen
sensor.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage
and check the connection of ECM har-
ness connector. Reconnect ECM harness
connector and retest.
INSPECTION END
SEF091U
SEF093U
SEF646P
SEF094U
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Heated Oxygen Sensor Heater
Ð LHD Models Ð (Cont'd)
EC-129

COMPONENT INSPECTION
Heated oxygen sensor heater
Check resistance between terminalsV3andV1.
Resistance: 2.3 - 4.3Wat 25ÉC (77ÉF)
Check continuity between terminals
V2andV1,V3andV2.
Continuity should not exist.
If NG, replace the heated oxygen sensor.
CAUTION:
Discard any heated oxygen sensor which has been dropped
from a height of more than 0.5 m (19.7 in) onto a hard sur-
face such as a concrete floor; use a new one.
SEF586Q
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Heated Oxygen Sensor Heater
Ð LHD Models Ð (Cont'd)
EC-130

Idle Air Control Valve (IACV) Ð Auxiliary Air
Control (AAC) Valve
SYSTEM DESCRIPTION
Camshaft position sensorcEngine speed
ECM
(ECCS
control
module)
cIACV-AAC valve
Mass air flow sensorcAmount of intake air
Engine coolant temperature sensor
cEngine coolant temperature
Ignition switch
cStart signal
Throttle position sensor
cThrottle position
Neutral position switch
cNeutral position
Air conditioner switch
cAir conditioner operation
Power steering oil pressure switch
cPower steering load signal
Battery
cBattery voltage
Vehicle speed sensor
cVehicle speed
This system automatically controls engine idle speed to a specified level. Idle speed is controlled through
fine adjustment of the amount of air which by-passes the throttle valve via IACV-AAC valve. The IACV-AAC
valve repeats ON/OFF operation according to the signal sent from the ECM. The camshaft position sensor
detects the actual engine speed and sends a signal to the ECM. The ECM then controls the ON/OFF time
of the IACV-AAC valve so that engine speed coincides with the target value memorized in ECM. The tar-
get engine speed is the lowest speed at which the engine can operate steadily. The optimum value stored
in the ECM is determined by taking into consideration various engine conditions, such as during warm up,
deceleration, and engine load (air conditioner and power steering operation).
COMPONENT DESCRIPTION
IACV-ACC valve
The IACV-AAC valve is moved by ON/OFF pulses from the
ECM. The longer the ON pulse, the greater the amount of air that
will flow through the valve. The more air that flows through the
valve, the higher the idle speed.
SEF040E
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
EC-131

CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
IACV-AAC/V
lEngine: After warming uplAir conditioner switch: ``OFF''lShift lever: Neutral positionlNo-loadIdle 20 - 40%
2,000 rpm Ð
ECM TERMINALS AND REFERENCE VALUE
Remarks: Specification data are reference values, and are measured between each terminal andV39(ECCS ground) with a voltme-
ter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC voltage)
113 W/G IACV-AAC valveEngine is running.
Idle speed10 - 13V
Engine is running.
Steering wheel is being turned.Air conditioner is operating.Rear window defogger switch is ``ON''.Lighting switch is ``ON''.5 - 10V
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Idle Air Control Valve (IACV) Ð Auxiliary Air
Control (AAC) Valve (Cont'd)
EC-132

HEC355
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Idle Air Control Valve (IACV) Ð Auxiliary Air
Control (AAC) Valve (Cont'd)
EC-133

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK OVERALL FUNCTION.
1. Start engine and warm it up suffi-
ciently.
2. Perform ``IACV-AAC/V SYS-
TEM'' in ``FUNCTION TEST''
mode with CONSULT.
----------------------------------------------------------------------------------------------------------------------------------OR----------------------------------------------------------------------------------------------------------------------------------
2. Perform ``IACV-AAC/V OPEN-
ING'' in ``ACTIVE TEST'' mode
with CONSULT.
3. Check engine speed varies cor-
responding to IACV-AAC
VALVE opening percent.
----------------------------------------------------------------------------------------------------------------------------------OR----------------------------------------------------------------------------------------------------------------------------------
2. Check idle speed.
800 50 rpm
If NG, adjust idle speed.
3. Stop engine and disconnect
throttle position sensor sub-
harness connector.
4. Restart engine and let it idle
after revving it to 2,000 - 3,000
rpm a few times.
5. Check idle speed again.
750 25 rpm
NG
cOK
INSPECTION END
CHECK POWER SUPPLY.
1. Stop engine.
2. Disconnect IACV-AAC valve harness
connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V3
and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
l10A fuse
lHarness connectorsF54,M48(RHD mod-
els)
lHarness for open or
short between IACV-
AAC valve and fuse
If NG, repair harness or
connectors.
VA
SEF152U
MEF176E
SEF164U
SEF148U
SEF095U
.
.
.
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Idle Air Control Valve (IACV) Ð Auxiliary Air
Control (AAC) Valve (Cont'd)
EC-134

VA
CHECK OUTPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM
terminal
113and terminalV1.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit, short
to ground or short to power
in harness or connectors.
CHECK COMPONENT
(IACV-AAC valve).
Refer to ``COMPONENT INSPECTION''
below.
OK
cNG
Replace IACV-AAC valve.
Disconnect and reconnect harness con-
nectors in the circuit. Then retest.
Trouble is not fixed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
COMPONENT INSPECTION
IACV-AAC valve
Disconnect IACV-AAC valve harness connector.
lCheck IACV-AAC valve resistance.
Resistance:
Approximately 10Wat 25ÉC (77ÉF)
lCheck plunger for seizing or sticking.
lCheck for broken spring.
SEF096U
SEF097U
.
.
.
.
.
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
Idle Air Control Valve (IACV) Ð Auxiliary Air
Control (AAC) Valve (Cont'd)
EC-135

Neutral Position Switch
COMPONENT DESCRIPTION
When the gear position is in ``Neutral'', neutral position is ``ON''.
ECM detects the position because the continuity of the line (the
``ON'' signal) exists.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
P/N POSI SW
lIgnition switch: ONShift lever: Neutral position ON
Except above OFF
ECM TERMINALS AND REFERENCE VALUE
Remarks: Specification data are reference values, and are measured between each terminal andV39(ECCS ground) with a voltme-
ter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC voltage)
35 L/B Neutral positionIgnition switch ``ON''
Neutral positionApproximately 0V
Ignition switch ``ON''
Except the above gear positionApproximately 5V
SEF098U
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
EC-136