NISSAN PICK-UP 2001 Repair Manual

6 CHECK COOLING FAN GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect cooling fan motor harness connector.
SEC232D
3. Check harness continuity between cooling fan relay terminal 3 and cooling fan motor terminals 1, cooling fan motor terminals 2
and body ground. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 7.
NGcRepair open circuit or short to ground or short to power in harness or connectors.
7 CHECK COOLING FAN OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Disconnect triple-pressure switch harness connector.
3. Check harness continuity between ECM terminal 14 and cooling fan relay terminal 1, cooling fan relay terminal 1 and triple-pres-
sure switch terminal 2, triple-pressure switch terminal 3 and ground. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OKcGO TO 9.
NGcGO TO 8.
8 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M5, E101
+Harness connectors M47, F55 (RHD models)
+Harness for open or short between cooling fan relay and ECM
+Harness for open or short between cooling fan relay and triple-pressure switch
+Harness for open or short between triple-pressure switch and ground
cRepair open circuit or short to ground or short to power in harness or connectors.
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3496

9 CHECK COOLING FAN RELAY
Check continuity between cooling fan relay terminals 3 and 5 under the following conditions.
SEC340C
OK or NG
OKcGO TO 10.
NGcReplace cooling fan relay.
10 CHECK COOLING FAN MOTOR
Supply battery voltage between the following terminals and check operation.
SEC162D
OK or NG
OKcGO TO 11.
NGcReplace cooling fan motor.
11 CHECK TRIPLE PRESSURE SWITCH
Refer to HA section.
OK or NG
OKcGO TO 12.
NGcReplace triple pressure switch.
12 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3469.
cINSPECTION END
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3497

13 CHECK COOLING SYSTEM FOR LEAK
Apply pressure to the cooling system with a tester, and check if the pressure drops.
Testing pressure: 157 kPa (1.57 bar, 1.6 kg/cm
2, 23 psi)
CAUTION:
Higher than the specified pressure may cause radiator damage.
SLC754A
Pressure should not drop.
OK or NG
OKcGO TO 15.
NGcGO TO 14.
14 DETECT MALFUNCTIONING PART
Check the following for leak.
+Hose
+Radiator
+Water pump (Refer to LC section, ªWater Pumpº.)
cRepair or replace.
15 CHECK RADIATOR CAP
Apply pressure to cap with a tester and check radiator cap relief pressure.
SLC755A
Radiator cap relief pressure:
79 - 98 kPa (0.78 - 0.98 bar, 0.8 - 1.0 kg/cm2, 11 - 14 psi)
OK or NG
OKcGO TO 16.
NGcReplace radiator cap.
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3498

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

18 CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to ªMAIN 12 CAUSES OF OVERHEATINGº, EC-3501.
cINSPECTION END
Main 12 Causes of Overheating
Engine Step Inspection item Equipment Standard Reference page
OFF 1+Blocked radiator
+Blocked condenser
+Blocked radiator grille
+Blocked bumper+Visual No blocking Ð
2+Coolant mixture+Coolant tester 30 - 50% coolant mixture See ªRECOMMENDED
FLUIDS AND LUBRI-
CANTSº in MA section.
3+Coolant level+Visual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA sec-
tion.
4+Radiator cap+Pressure tester 78 - 98 kPa
(0.78 - 0.98 bar, 0.8 - 1.0
kg/cm
2, 11 - 14 psi)
59 - 98 kPa (0.59 - 0.98
bar, 0.6 - 1.0 kg/cm
2,
9 - 14 psi) (Limit)See ªSystem Checkº,
ªENGINE COOLING SYS-
TEMº in LC section.
ON*2 5+Coolant leaks+Visual No leaks See ªSystem Checkº,
ªENGINE COOLING SYS-
TEMº in LC section.
ON*2 6+Thermostat+Touch the upper and
lower radiator hosesBoth hoses should be hot. See ªThermostatº and
ªRadiatorº, ªENGINE
COOLING SYSTEMº in
LC section.
ON*1 7+Cooling fan+Visual Operating See ªDTC 0208 OVER
HEATº, EC-3489.
OFF 8+Combustion gas leak+Color checker chemical
tester 4 gas analyzerNegative Ð
ON*3 9+Coolant temperature
gauge+Visual Gauge less than 3/4
when drivingÐ
+Coolant overflow to res-
ervoir tank+Visual No overflow during driving
and idlingSee ªChanging Engine
Coolantº, ªENGINE MAIN-
TENANCEº in MA sec-
tion.
OFF*4 10+Coolant return from res-
ervoir tank to radiator+Visual Should be initial level in
reservoir tankSee ªENGINE MAINTE-
NANCEº in MA section.
OFF 11+Cylinder head+Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See ªInspectionº, ªCYLIN-
DER HEADº in EM sec-
tion.
12+Cylinder block and pis-
tons+Visual No scuffing on cylinder
walls or pistonSee ªInspectionº, ªCYLIN-
DER BLOCKº in EM sec-
tion.
*1: Engine running at idle.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to ªOVERHEATING CAUSE ANALYSISº in LC section.
DTC 0208 OVER HEATYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3500

Description
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The unit controls the
engine.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
+ECM calculation function is malfunctioning.+ECM
(ECCS-D control module)
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait at least 2 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-3503.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 2 seconds.
2) Start engine and wait at least 2 seconds.
3) Turn ignition switch ªOFFº, wait at least 5 seconds and then
turn ªONº.
4) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º
with ECM.
5) If DTC is detected, go to ªDiagnostic Procedureº, EC-3503.
SEC220B
SEF817Y
DTC 0301 ECM 2, DTC 901 ECM 12YD25DDTi
EC-3501

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

Wiring Diagram
GEC128A
DTC 0401 INTAKE AIR TEMPERATURE SENSORYD25DDTi
EC-3505