2001 NISSAN PICK-UP sensor

Description
SYSTEM DESCRIPTION
Sensor Input signal to ECM ECM function Actuator
Vehicle speed sensor Vehicle speed
Cooling fan con-
trolCooling fan relay Engine coolant temperature sensor Engine coolant temperature
Air conditioner switch Air conditioner ªONº signal
The ECM controls the cooling fan corresponding to the vehicle speed, engine coolant temperature. The
control system has 2-step control [ON/OFF].
OPERATION
*: Refer to HA section.
CONSULT-II Reference Value in Data Monitor
Mode
Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
AIR COND RLY+Engine: After warming up, idle
the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)ON
COOLING FAN+When cooling fan is stopped. OFF
+When cooling fan operates. ON
SEC242D
DTC 0208 OVER HEATYD25DDTi
EC-3489

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 CONDITION DATA (DC Voltage)
14 G/B Cooling fan relayEngine is running.
Cooling fan is not operatingBATTERY VOLTAGE
(11 - 14V)
Engine is running.
Cooling fan is operatingApproximately 0.1V
On Board Diagnosis Logic
This diagnosis continuously monitors the engine coolant temperature.
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
Malfunction is detected when ... Check Items (Possible Cause)
+Cooling fan does not operate properly (Overheat).
+Cooling fan system does not operate properly (Overheat).
+Engine coolant was not added to the system using the proper
filling method.+Harness or connectors
(The cooling fan circuit is open or shorted.)
+Cooling fan
+Radiator hose
+Radiator
+Radiator cap
+Water pump
+Thermostat
+Fan belt
+Engine coolant temperature sensor
For more information, refer to ªMAIN 12 CAUSES OF
OVERHEATINGº, EC-3501.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the MA
section (ªChanging Engine Coolantº, ªENGINE MAINTENANCEº). Also, replace the engine oil.
1) Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure
to use coolant with the proper mixture ratio. Refer to MA section (ªAnti-freeze Coolant Mixture
Ratioº, ªRECOMMENDED LUBRICANTS AND FLUIDSº).
2) After refilling coolant, run engine to ensure that no water-flow noise is emitted.
DTC 0208 OVER HEATYD25DDTi
EC-3490

Overall Function Check
Use this procedure to check the overall function of the cooling
fan. During this check, a DTC might not be confirmed.
WARNING:
Never remove the radiator cap when the engine is hot. Seri-
ous burns could be caused by high pressure fluid escaping
from the radiator.
Wrap a thick cloth around the cap. Carefully remove the cap
by turning it a quarter turn to allow built-up pressure to
escape. Then turn the cap all the way off.
WITH CONSULT-II
1) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is
below the proper range, skip the following steps and go to
ªDiagnostic Procedureº, EC-3494.
2) Confirm whether customer filled the coolant or not. If cus-
tomer filled the coolant, skip the following steps and go to
ªDiagnostic Procedureº, EC-3494.
3) Turn ignition switch ªONº.
4) Perform ªCOOLING FANº in ªACTIVE TESTº mode with
CONSULT-II and make sure that cooling fans operate when
touching ªONº or ªOFFº.
If NG, go to ªDiagnostic Procedureº, EC-3494.
WITHOUT CONSULT-II
1) Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is
below the proper range, skip the following steps and go to
ªDiagnostic Procedureº, EC-3494.
2) Confirm whether customer filled the coolant or not. If cus-
tomer filled the coolant, skip the following steps and go to
ªDiagnostic Procedureº, EC-3494.
3) Disconnect engine coolant temperature sensor harness con-
nector.
4) Connect 150Wresistor to engine coolant temperature sensor
harness connector.
5) Start engine and make sure that cooling fan operates.
Be careful not to overheat engine.
6) If NG, go to ªDiagnostic Procedureº, EC-3494.
AEC640
SEF111X
SEC636CA
DTC 0208 OVER HEATYD25DDTi
EC-3491

3 CHECK COOLING FAN OPERATION
Without CONSULT-II
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect 150Wresistor to engine coolant temperature sensor harness connector.
4. Restart engine and make sure that cooling fan operates.
SEC636CA
OK or NG
OKcGO TO 13.
NGcGO TO 4.
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3494

16 CHECK THERMOSTAT
1. Remove thermostat.
2. Check valve seating condition at normal room temperatures.
It should seat tightly.
3. Check valve opening temperature and valve lift.
SLC343
Valve opening temperature:
82ÉC (180ÉF) [standard]
Valve lift:
More than 10 mm/95ÉC (0.394 in/203ÉF)
4. Check if valve is closed at 5ÉC (9ÉF) below valve opening temperature. For details, refer to LC section, ªThermostatº.
OK or NG
OKcGO TO 17.
NGcReplace thermostat.
17 CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Remove engine coolant temperature sensor.
2. Check resistance between engine coolant temperature sensor terminals 1 and 2 as shown in the figure.
SEF304X
OK or NG
OKcGO TO 18.
NGcReplace engine coolant temperature sensor.
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3499

Diagnostic Procedure
1 INSPECTION START
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªSELF DIAG RESULTSº mode with CONSULT-II.
3. Touch ªERASEº.
4. Perform ªDTC Confirmation Procedureº, EC-3501, again.
5. Is the malfunction displayed again?
Without CONSULT-II
1. Turn ignition switch ªONº.
2. Erase the Diagnostic Test Mode II (Self-diagnostic results) memory.
3. Perform ªDTC Confirmation Procedureº, EC-3501, again.
4. Perform ªDiagnostic Test Mode II (Self-diagnostic results)º.
5. Is the DTC 0301 or 0901 displayed again?
Yes or No
YescGO TO 2.
NocINSPECTION END
2 REPLACE ECM
1. Replace ECM.
2. Perform initialization of NATS system and resistration of all NATS ignition key IDs. Refer to EC-3429. (Models with NATS)
3. Perform ªAccelerator Position Sensor Idle Position Learningº of ªBASIC SERVICE PROCEDUREº. Refer to EC-3427.
cINSPECTION END
DTC 0301 ECM 2, DTC 901 ECM 12YD25DDTi
EC-3502

Component Description
The intake air temperature sensor is mounted to the air duct
housing. The sensor detects intake air temperature and trans-
mits 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)Voltage*
VResistance
kW
20 (68) 3.5 2.1 - 2.9
80 (176) 1.24 0.27 - 0.38
*: These data are reference values and are measured between ECM terminal
36 (Intake air temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to 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 low or high voltage from the sensor is sent to
ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Intake air 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-3507.
SEC229D
SEF012P
SEF817Y
DTC 0401 INTAKE AIR TEMPERATURE SENSORYD25DDTi
EC-3503

WITHOUT CONSULT-II
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 EC-3507.
DTC 0401 INTAKE AIR TEMPERATURE SENSORYD25DDTi
DTC Confirmation Procedure (Cont'd)
EC-3504