2001 NISSAN PICK-UP Repair Manual

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) 2.3 0.68 - 1.0
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and measured between ECM terminal 19
(Engine coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/
output voltage. Doing so may damage the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
+An excessively high or low voltage from the sensor is entered
to ECM.+Harness or connectors (The sensor circuit is open or shorted.)
+Engine coolant temperature sensor
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-3483.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 5 seconds.
2) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
3) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º
with ECM.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-3483.
SEF594K
SEF012P
SEF817Y
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3480

Wiring Diagram
GEC274A
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3481

Diagnostic Procedure
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
SEC230D
3. Turn ignition switch ªONº.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
OK or NG
OKcGO TO 3.
NGcGO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E237, M279 (LHD models)
+Harness connectors E237, F36 (RHD models)
+Harness for open or short between engine control temperature sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
3 CHECK ECTS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between ECTS terminal 1 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 5.
NGcGO TO 4.
DTC 0103 COOLANT TEMP SENYD25DDTi
EC-3482

4 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E237, M279 (LHD models)
+Harness connectors E237, F36 (RHD models)
+Harness for open or short between engine coolant temperature sensor and ECM
cRepair open circuit or short to ground or short to power in harness or connectors.
5 CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Remove engine coolant temperature sensor from the engine.
2. Check resistance between ECTS terminals 1 and 2 as shown in the figure.
SEF304X
OK or NG
OKcGO TO 6.
NGcReplace engine coolant temperature sensor.
6 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3469.
cINSPECTION END
DTC 0103 COOLANT TEMP SENYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3483

Description
The vehicle speed sensor is installed in the transaxle. It contains
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
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may damage the
ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA (DC Voltage and
Pulse Signal)
26 W/L Vehicle speed sensorEngine is running.
Lift up the vehicle
In 1st gear position
Vehicle speed is 10 km/h (6 MPH)Approximately 4.6V
SEF257Z
Engine is running.
Lift up the vehicle
In 2nd gear position
Vehicle speed is 30 km/h (19 MPH)Approximately 2.2V
SEF258Z
On Board Diagnosis Logic
Malfunction is detected when .... Check Items (Possible Cause)
+The almost 0 km/h (0 MPH) signal from vehicle speed sensor
is sent to ECM even when vehicle is being driven.+Harness or connector
(The vehicle speed sensor circuit is open or shorted.)
+Vehicle speed sensor
PBIB0281E
DTC 0104 VEHICLE SPEED SENYD25DDTi
EC-3484

Overall Function Check
Use this procedure to check the overall function of the vehicle
speed sensor circuit. During this check, a DTC might not be
confirmed.
WITH CONSULT-II
1) Lift up the vehicle.
2) Start engine.
3) Read vehicle speed sensor signal in ªDATA MONITORº
mode with CONSULT-II.
The vehicle speed on CONSULT-II should be able to
exceed 10 km/h (6 MPH) when rotating wheels with suit-
able gear position.
4) If NG, go to ªDiagnostic Procedureº, EC-3489.
WITHOUT CONSULT-II
1) Lift up the vehicle.
2) Start engine.
3) Rotate drive wheel by hand.
4) Check voltage between ECM terminal 26 and ground with
tester.
Voltage should vary between 0 - 4.8V.
5) If NG, go to ªDiagnostic Procedureº, EC-3489.
SEF864Y
SEF811R
DTC 0104 VEHICLE SPEED SENYD25DDTi
EC-3485

Wiring Diagram
MODELS WITH TACHOMETER
GEC130A
DTC 0104 VEHICLE SPEED SENYD25DDTi
EC-3486

MODELS WITHOUT TACHOMETER
GEC131A
DTC 0104 VEHICLE SPEED SENYD25DDTi
Wiring Diagram (Cont'd)
EC-3487