NISSAN PICK-UP 1998 Repair Manual

Intake Air Temperature Sensor
The intake air temperature sensor is mounted to the air duct. The
sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a thermistor, which is sensi-
tive to the change in temperature. Electrical resistance of the
thermistor decreases in response to the temperature rise.

Intake air temperature
ÉC (ÉF)Resistance kW
þ10 (14) 7.0 - 11.4
20 (68) 2.1 - 2.9
80 (176) 0.27 - 0.38
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ...Check Items
(Possible Cause)
41
lAn excessively low or high voltage from the sensor is
sent to ECM*.lHarness or connectors
(The sensor circuit is open or shorted.)
lIntake air temperature sensor
*: When this malfunction is detected, the ECM enters fail-safe mode.
Engine operating condition in fail-safe modeThe ECM controls on the assumption that the intake temperature
is 20ÉC (68ÉF).
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON''.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Wait at least 2 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'' and wait at least 2 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.
SEF086U
SEF012P
SEF002P
TROUBLE DIAGNOSIS FOR ``INT AIR TEMP SEN'' (DTC 41)KA
EC-109

HEC346
TROUBLE DIAGNOSIS FOR ``INT AIR TEMP SEN'' (DTC 41)KA
Intake Air Temperature Sensor (Cont'd)
EC-110

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect intake air temperature sen-
sor harness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V1
and ground.
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
V2and 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
intake air temperature
sensor
If NG, repair open circuit,
short to ground or short to
power in harness or con-
nectors.
CHECK COMPONENT
(Intake air temperature sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace intake air tem-
perature 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
SEF086U
SEF101S
SEF102S
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``INT AIR TEMP SEN'' (DTC 41)KA
Intake Air Temperature Sensor (Cont'd)
EC-111

COMPONENT INSPECTION
Intake air temperature sensor
Check resistance as shown in the figure.

Intake air temperature
ÉC (ÉF)Resistance kW
20 (68) 2.1 - 2.9
80 (176) 0.27 - 0.38
If NG, replace intake air temperature sensor.
SEF103S
SEF012P
TROUBLE DIAGNOSIS FOR ``INT AIR TEMP SEN'' (DTC 41)KA
Intake Air Temperature Sensor (Cont'd)
EC-112

Throttle Position Sensor
COMPONENT DESCRIPTION
The throttle position sensor responds to the accelerator pedal
movement. This sensor is a kind of potentiometer which trans-
forms the throttle position into output voltage, and emits the
voltage signal to the ECM. In addition, the sensor detects the
opening and closing speed of the throttle valve and feeds the
voltage signal to the ECM.
Idle position of the throttle valve is determined by the ECM
receiving the signal from the throttle position sensor. This one
controls engine operation such as fuel cut.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
THRTL POS SEN
lIgnition switch: ON
(Engine stopped)Throttle valve: fully closed 0.35 - 0.65V
Throttle valve: fully opened Approx. 4.0V
CLSD THL/POSI
lIgnition switch: ON
(Engine stopped)Throttle valve: Idle position ON
Throttle valve: Slightly open 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)
20 LGThrottle position sensor
signalIgnition switch ``ON''
(Warm-up condition)
Accelerator pedal released0.35 - 0.65V
Ignition switch ``ON''
Accelerator pedal fully depressedApproximately 4V
37 PUThrottle position sensor
power supplyIgnition switch ``ON''
Approximately 5V
21
29B/G
B/GSensors' groundEngine is running.
(Warm-up condition)
Idle speed0.001 - 0.02V
SEF520Q
TROUBLE DIAGNOSIS FOR ``THROTTLE POSI SEN'' (DTC 43)KA
EC-113

ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble
Code No.Malfunction is detected when ...Check Items
(Possible Cause)
43
lAn excessively low or high voltage from the sensor is
sent to ECM.*lHarness or connectors
(The sensor circuit is open or shorted.)
lThrottle position sensor
*: When this malfunction is detected, the ECM enters fail-safe mode.
Engine operating condition in fail-safe mode Condition Driving condition
Throttle position will be determined based on the
amount of mass air flow and the engine speed.
Therefore, acceleration will be poor.When engine is idling Normal
When accelerating Poor acceleration
OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the throttle
position sensor circuit. During this check, a DTC might not be
confirmed.
1) Start engine and warm it up sufficiently.
2) Turn ignition switch ``OFF'' and wait at least 5 seconds.
3) Turn ignition switch ``ON''.
4) Select ``THRTL POS SEN'' in ``DATA MONITOR'' mode
with CONSULT.
5) Read ``THRTL POS SEN'' signal and check the follow-
ing:
lThe voltage when accelerator pedal fully released is
approximately 0.35 - 0.65V.
lThe voltage when accelerator pedal fully depressed
is approximately 4V.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and warm it up sufficiently.
2) Turn ignition switch ``OFF'' and wait at least 5 seconds.
3) Turn ignition switch ``ON''.
4) Check the voltage between ECM terminals
V20andV39
(ground) and check the following:
lThe voltage when accelerator pedal fully released is
approximately 0.35 - 0.65V.
lThe voltage when accelerator pedal fully depressed
is approximately 4V.
SEF770T
SEF771T
SEF087U
TROUBLE DIAGNOSIS FOR ``THROTTLE POSI SEN'' (DTC 43)KA
Throttle Position Sensor (Cont'd)
EC-114

HEC347
TROUBLE DIAGNOSIS FOR ``THROTTLE POSI SEN'' (DTC 43)KA
Throttle Position Sensor (Cont'd)
EC-115

DIAGNOSTIC PROCEDURE
INSPECTION START
ADJUST THROTTLE POSITION SEN-
SOR.
Perform BASIC INSPECTION, EC-58.
OK
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 throttle position sensor har-
ness connector.
2. Turn ignition switch ``ON''.
3. Check voltage between terminal
V1
and ground with CONSULT or tester.
Voltage: Approximately 5V
OK
cNG
Check the following.
lHarness connectorsM205,M301(LHD mod-
els)
F5,F101(RHD mod-
els)
lHarness for open or
short between throttle
position sensor and
ECM
If NG, repair harness or
connectors.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Check harness continuity between ter-
minal
V3and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
lHarness connectorsM205,M301(LHD mod-
els)
F5,F101(RHD mod-
els)
lHarness for open or
short between throttle
position sensor and
ECM
If NG, repair open circuit,
short to ground or short to
power in harness or con-
nectors.
VA
SEF076U
SEF160U
SEF107S
SEF108S
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``THROTTLE POSI SEN'' (DTC 43)KA
Throttle Position Sensor (Cont'd)
EC-116

VA
CHECK INPUT SIGNAL CIRCUIT.
1. Disconnect ECM harness connector.
2. Check harness continuity between
ECM terminal
V20and terminalV2.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
lHarness connectorsM205,M301(LHD models)
F5,F101(RHD models)
lHarness for open or short
between throttle position
sensor and ECM
If NG, repair open circuit,
short to ground or short to
power in harness or connec-
tors.
CHECK COMPONENT
(Throttle position sensor).
Refer to ``COMPONENT INSPECTION''
below.
OK
cNG
Replace throttle position
sensor. To adjust it, perform
BASIC INSPECTION,
EC-58.
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
COMPONENT INSPECTION
Throttle position sensor
1. Start engine and warm it up sufficiently.
2. Turn ignition switch ``OFF''.
3. Disconnect throttle position sensor harness connector.
4. Make sure that resistance between terminals
V2andV3
changes when opening throttle valve manually.
Throttle valve conditions Resistance at 25ÉC (77ÉF)
Completely closed Approximately 0.6 kW
Partially open 0.6 - 4.0 kW
Completely open Approximately 4 kW
If NG, replace throttle position sensor.
To adjust throttle position sensor, perform ``BASIC
INSPECTION'', EC-58.
SEF088U
SEF161U
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``THROTTLE POSI SEN'' (DTC 43)KA
Throttle Position Sensor (Cont'd)
EC-117

Vehicle Speed Sensor (VSS)
COMPONENT DESCRIPTION
The vehicle speed sensor is installed in the transmission. It con-
tains a pulse generator which provides a vehicle speed signal to
the speedometer. The speedometer then sends a signal to the
ECM.
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)
32 W/L Vehicle speed sensorEngine is running.
Jack up all wheels and run engine at idle in
1st position.Varies from 0 to 5V
SEF068U
SEF089U
TROUBLE DIAGNOSIS FOR NON-DETECTABLE ITEMSKA
EC-118