2001 NISSAN PICK-UP engine

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

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

3 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between terminal 1 and engine ground.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OKcGO TO 5.
NGcGO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E101, M5
+Harness connectors M48, F54 (RHD models)
+Harness for open or short between ECM and intake air temperature sensor
cRepair open circuit or short to power in harness or connectors.
5 CHECK INTAKE AIR TEMPERATURE SENSOR
Check resistance between intake air temperature sensor terminals 1 and 2 as shown in the figure.
SEC165D
OK or NG
OKcGO TO 6.
NGcReplace intake air temperature sensor.
6 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3469.
cINSPECTION END
DTC 0401 INTAKE AIR TEMPERATURE SENSORYD25DDTi
Diagnostic Procedure (Cont'd)
EC-3507

Description
SYSTEM DESCRIPTION
The ECM and the electronic control fuel injection pump control
unit (abbreviated as the injection pump control unit) perform the
real time communication (signal exchange).
The ECM transmits the signals of the target fuel injection
amount, target fuel injection timing, and engine speed, etc., and
receives the signals of the pump speed and fuel temperature,
etc. from the injection pump control unit.
By those signals, the injection pump controls the optimum fuel
injection amount and injection timing of the spill valve and tim-
ing control valve.
Injection pump control unit has an on board diagnostic system,
which detects malfunctions related to sensors or actuators built-
into electronic control fuel injection pump. These malfunction
information are transferred through the line (circuit) from injection
pump control unit to ECM.
FUEL INJECTION AMOUNT CONTROL
In accordance with the target fuel injection amount signal from
the ECM, the injection amount is controlled by controlling the spill
valve in the injection pump and by changing the needle opening
time.
FUEL INJECTION TIMING CONTROL
Based on the target fuel injection timing signal from the ECM, the
injection timing is controlled in accordance with the timer spring
by performing the duty control of the timing control valve in the
injection pump and by adjusting the pressure of the timer piston
high pressure chamber.
FUEL TEMPERATURE SENSOR
The sensor detects the fuel temperature in the injection pump
and calibrates the injection amount change by the fuel tempera-
ture.
CAM RING POSITION SENSOR
The sensor detects the passing of the protrusion on the sensor
wheel in the injection pump by the semiconductor magnetic
resistance element sensor. The cam ring position sensor syn-
chronizes with the cam ring, and detects the actual advance
amount. The injection pump control unit measures the injection
pump revolution by the signal of the cam ring position sensor.
SEF437Y
DTC 0402 P9zFUEL TEMP SENYD25DDTi
EC-3508