1998 NISSAN PICK-UP engine

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK SHIELD CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Loosen and retighten engine ground
screws.
3. Remove joint connector
M31orF53.
4. Check the following.
lContinuity between joint connector
terminal
V1and ground
lJoint connector
(Refer to ``HARNESS LAYOUT'' in EL
section.)
Continuity should exist.
If OK, check harness for short to
ground and short to power. Then
reconnect joint connector.
OK
cNG
Repair open circuit, short
to ground or short to
power in harness or con-
nectors.
CHECK POWER SUPPLY.
1. Disconnect mass air flow sensor har-
ness connector.
2. Turn ignition switch ``ON''.
3. Check voltage between terminal
V3
and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
lHarness connectorsM5,E101
lHarness connectorsF54,M48(RHD mod-
els)
lHarness for open or
short between mass air
flow sensor and ECM
lHarness for open or
short between mass air
flow sensor and ECCS
relay
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
V2and ECM terminalV17.
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 con-
nectors.
CHECK INPUT SIGNAL CIRCUIT.
Check harness continuity between termi-
nal
V1and ECM terminalV16.
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 con-
nectors.
VA
SEF076U
SEF150U
SEF079U
SEF080U
SEF081U
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)KA
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-93

VA
CHECK COMPONENT
(Mass air flow sensor).
Refer to ``COMPONENT INSPECTION''
below.
OK
cNG
Replace mass air flow
sensor.
Disconnect and reconnect harness con-
nectors in the circuits. 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
COMPONENT INSPECTION
Mass air flow sensor
1. Turn ignition switch ``ON''.
2. Start engine and warm it up sufficiently.
3. Check voltage between terminal
V1and ground.
Conditions Voltage V
Ignition switch ``ON'' (Engine stopped.) Less than 1.0
Idle (Engine is warmed-up sufficiently.) 1.3 - 1.7
2,500 rpm 1.7 - 2.1
Idle to about 4,000 rpm* 1.3 - 1.7 to Approx. 4.0
*: Check for linear voltage rise in response to increase to about 4,000 rpm in
engine speed.
4. If NG, remove mass air flow sensor from air duct. Check hot
wire for damage or dust.
SEF082U
SEF893J
.
.
.
.
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)KA
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-94

Engine Coolant Temperature Sensor (ECTS)
COMPONENT DESCRIPTION
The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage sig-
nal from the ECM. The modified signal returns to the ECM as the
engine coolant temperature input. The sensor uses a thermistor
which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature
increases.

Engine coolant tempera-
ture
ÉC (ÉF)Voltage*
(V)Resistance
(kW)
þ10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and are measured between ECM termi-
nal
V18(Engine coolant temperature sensor) and ECM terminalV39(ECCS
ground).
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ...Check Items
(Possible Cause)
13
lAn excessively high or low voltage from the sensor is
sent to ECM.*lHarness or connectors
(The sensor circuit is open or shorted.)
lEngine coolant temperature sensor
*: When this malfunction is detected, the ECM enters fail-safe mode.
Engine operating condition in fail-safe mode ConditionEngine coolant temperature decided
(CONSULT DISPLAY)
Engine coolant temperature will be determined
by ECM based on the time after turning igni-
tion switch ``ON'' or ``START''.
CONSULT displays the engine coolant tem-
perature decided by ECM.Just as ignition switch is turned ON or START 20ÉC (68ÉF)
More than 6 minutes after ignition START 80ÉC (176ÉF)
Except as shown above20 - 80ÉC (68 - 176ÉF)
(Depends on the time)
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 5 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'' and wait at least 5 seconds.
2) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
3) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF594K
SEF012P
SEF759T
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)KA
EC-95

HEC343
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)KA
Engine Coolant Temperature Sensor (ECTS)
(Cont'd)
EC-96

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect engine coolant temperature
sensor harness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V2
and ground with CONSULT or tester.
Voltage:
Approximately 5V
OK
cNG
Repair harness or connec-
tors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Check harness continuity between ter-
minal
V1and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
lHarness for open or
short between ECM and
engine coolant tempera-
ture sensor
If NG, repair open circuit,
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Engine coolant temperature sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace engine coolant
temperature 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
SEF083U
SEF645R
SEF646R
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)KA
Engine Coolant Temperature Sensor (ECTS)
(Cont'd)
EC-97

COMPONENT INSPECTION
Engine coolant temperature sensor
Check resistance as shown in the figure.

Temperature ÉC (ÉF) Resistance kW
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
If NG, replace engine coolant temperature sensor.
SEF152P
SEF012P
TROUBLE DIAGNOSIS FOR ``COOLANT TEMP SEN'' (DTC 13)KA
Engine Coolant Temperature Sensor (ECTS)
(Cont'd)
EC-98

Ignition Signal
COMPONENT DESCRIPTION
Ignition coil & power transistor (Built into distributor)
The ignition signal from the ECM is sent to and amplified by the
power transistor. The power transistor turns on and off the igni-
tion coil primary circuit. This on-off operation induces the proper
high voltage in the coil secondary circuit.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
IGN TIMING
lEngine: After warming uplAir conditioner switch: ``OFF''lShift lever: Neutral positionlNo-loadIdle 10É BTDC
2,000 rpm More than 25É BTDC
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)
1 W/PU Ignition signalEngine is running.
Idle speedApproximately 0.3V
SEF058U
Engine is running.
Engine speed is 2,000 rpm.Approximately 0.7V
SEF059U
SEF128S
TROUBLE DIAGNOSIS FOR ``IGN SIGNAL-PRIMARY'' (DTC 21)KA
EC-99

TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC voltage)
3 W/G Ignition checkEngine is running.
Idle speedApproximately 13V
SEF062U
Engine is running.
Engine speed is 2,000 rpm.Approximately 13V
SEF063U
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble
Code No.Malfunction is detected when ...Check Items
(Possible Cause)
21
lThe ignition signal in the primary circuit is not sent
during engine cranking or running.lHarness or connectors
(The ignition primary circuit is open or shorted.)
lPower transistor
lResistor
lCamshaft position sensor
lCamshaft position sensor circuit
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
Note: If both DTC 21 and DTC 11 are displayed, perform
TROUBLE DIAGNOSIS FOR DTC 11 first. (See EC-82.)
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Start engine and wait at least 2 seconds. (If engine
does not run, turn ignition switch to ``START'' for at
least 5 seconds.)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON''.
2) Start engine and wait at least 2 seconds. (If engine
does not run, turn ignition switch to ``START'' for at
least 5 seconds.)
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.SEF051U
TROUBLE DIAGNOSIS FOR ``IGN SIGNAL-PRIMARY'' (DTC 21)KA
Ignition Signal (Cont'd)
EC-100