2001 NISSAN PICK-UP Repair Manual

Introduction
The engine has an ECM to control major systems such as fuel
injection control, fuel injection timing control, glow control
system, etc. The ECM accepts input signals from sensors and
instantly drives electronic control fuel injection pump. It is essen-
tial that both input and output signals are proper and stable. At
the same time, it is important that there are no problems such as
vacuum leaks, or other problems with the engine.
It is much more difficult to diagnose a problem that occurs inter-
mittently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A
road test with CONSULT-II or a circuit tester connected should
be performed. Follow the ªWork Flowº, EC-3443.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The
customer can supply good information about such problems,
especially intermittent ones. Find out what symptoms are present
and under what conditions they occur. A ªDiagnostic Worksheetº
like the example on next page should be used.
Start your diagnosis by looking for ªconventionalº problems first.
This will help troubleshoot driveability problems on an electroni-
cally controlled engine vehicle.
DIAGNOSTIC WORKSHEET
There are many operating conditions that lead to the malfunction
of engine components. A good grasp of such conditions can
make troubleshooting faster and more accurate.
In general, each customer feels differently about a problem. It is
important to fully understand the symptoms or conditions for a
customer complaint.
Utilize a diagnostic worksheet like the one shown below in order
to organize all the information for troubleshooting.
SEF858S
SEF233G
SEF234G
SEF907L
TROUBLE DIAGNOSIS Ð INTRODUCTIONYD25DDTi
EC-3440

Worksheet sample
MTBL0397
TROUBLE DIAGNOSIS Ð INTRODUCTIONYD25DDTi
Introduction (Cont'd)
EC-3441

Work Flow
*1 Refer to MA section (ªChecking and
Replacing Fuel Filter and Draining
Waterº, ªENGINE MAINTENANCEº).
*2 If time data of ªSELF-DIAG
RESULTSº is other than ª0º, per-
form ªTROUBLE DIAGNOSIS FOR
INTERMITTENT INCIDENTº,
EC-3470.*3 If the incident cannot be verified,
perform ªTROUBLE DIAGNOSIS
FOR INTERMITTENT INCIDENTº,
EC-3470.
*4 If the on board diagnostic system
cannot be performed, check main
power supply and ground circuit.
Refer to ªTROUBLE DIAGNOSISFOR POWER SUPPLYº, EC-3471.
*5 If malfunctioning part cannot be
detected, perform ªTROUBLE
DIAGNOSIS FOR INTERMITTENT
INCIDENTº, EC-3470.SEF374YC
TROUBLE DIAGNOSIS Ð INTRODUCTIONYD25DDTi
EC-3442

DESCRIPTION FOR WORK FLOW
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using
the ªDIAGNOSTIC WORKSHEETº, EC-3440.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II) the DTC, then erase the
DTC. Refer to EC-3428.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3470.
Study the relationship between the cause, specified by DTC, and the symptom described by the customer. (The
ªSymptom Matrix Chartº will be useful. Refer to EC-3451.) Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The ªDIAGNOSTIC WORK SHEETº is useful to verify the incident. Connect CONSULT-II to the vehicle in DATA
MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3470.
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the DTC by driving in (or performing) the ªDTC Confirmation Procedureº. Check and read the DTC
by using CONSULT-II.
During the DTC verification, be sure to connect CONSULT-II to the vehicle in DATA MONITOR (AUTO TRIG)
mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-3470.
In case the ªDTC Confirmation Procedureº is not available, perform the ªOverall Function Checkº instead. The
DTC cannot be displayed by this check, however, this simplified ªcheckº is an effective alternative.
The ªNGº result of the ªOverall Function Checkº is the same as the DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to TROUBLE DIAGNOSIS FOR DTC XXXX.
If the normal code is indicated, proceed to the Basic Inspection, EC-3445. Then perform inspections according to
the Symptom Matrix Chart. Refer to EC-3451.
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes.
Inspect the system for mechanical binding, loose connectors or wiring damage using (tracing) ªHarness Layoutsº.
Gently shake the related connectors, components or wiring harness with CONSULT-II set in ªDATA MONITOR
(AUTO TRIG)º mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CON-
SULT-II. Refer to EC-3464 or EC-3461.
The ªDiagnostic Procedureº in EC section contains a description based on open circuit inspection. A short circuit
inspection is also required for the circuit check in the Diagnostic Procedure. For details, refer to GI section (ªCir-
cuit Inspectionº, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº).
Repair or replace the malfunction parts.
If the malfunctioning part cannot be detected, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENTº, EC-3470.
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions
and circumstances which resulted in the customer's initial complaint.
Perform the ªDTC Confirmation Procedureº and confirm the normal code (DTC No. 0505) is detected. If the inci-
dent is still detected in the final check, perform STEP VI by using a different method from the previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) DTC in ECM.
(Refer to EC-3428.)
TROUBLE DIAGNOSIS Ð INTRODUCTIONYD25DDTi
Work Flow (Cont'd)
EC-3443

Basic Inspection
Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
+Shift lever is in neutral position,
+Heat up switch is OFF,
+Headlamp switch is OFF,
+Air conditioner switch is OFF,
+Rear defogger switch is OFF,
+Steering wheel is in the straight-ahead position, etc.
1 INSPECTION START
1. Check service records for any recent repairs that may indicate a related problem.
2. Check the current need for scheduled maintenance, especially for fuel filter and air cleaner filter. Refer to MA section.
3. Open engine hood and check the following:
+Harness connectors for improper connections
+Vacuum hoses for splits, kinks, or improper connections
+Wiring for improper connections, pinches, or cuts
SEF142I
4. Start engine and warm it up to the normal operating temperature.
cGO TO 2.
2 PREPARATION FOR CHECKING IDLE SPEED
With CONSULT-II
Connect CONSULT-II to the data link connector.
Without CONSULT-II
Install diesel tacho tester to the vehicle.
cGO TO 3.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONYD25DDTi
EC-3444

3 CHECK IDLE SPEED
With CONSULT-II
1. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
2. Read idle speed.
SEF817Y
Without CONSULT-II
Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 4.
4 BLEED AIR FROM FUEL SYSTEM
1. Stop engine.
2. Using priming pump, bleed air from fuel system. Refer to ªAir Bleedingº, EC-3426.
cGO TO 5.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONYD25DDTi
Basic Inspection (Cont'd)
EC-3445

5 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 6.
6 DRIN WATER FROM FUEL FILTER
Drain water from fuel filter. Refer to MA section (ªChecking and Replacing Fuel Filter and Draining Waterº, ªENGINE MAINTE-
NANCEº).
cGO TO 7.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONYD25DDTi
Basic Inspection (Cont'd)
EC-3446

7 CHECK IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and let it idle.
2. Select ªCKPSzRPM (TDC)º in ªDATA MONITORº mode with CONSULT-II.
3. Read idle speed.
SEF817Y
Without CONSULT-II
1. Start engine and let it idle.
2. Check idle speed.
750 25 rpm
OK or NG
OKcINSPECTION END
NGcGO TO 8.
8 CHECK AIR CLEANER FILTER
Check air cleaner filter for clogging or breaks.
OK or NG
OKcGO TO 9.
NGcReplace air cleaner filter.
9 CHECK FUEL INJECTION NOZZLE
Check fuel injection nozzle opening pressure. Refer to ªInjection pressure testº, EC-3418.
OK or NG
OKcGO TO 10.
NGcReplace fuel injection nozzle assembly.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONYD25DDTi
Basic Inspection (Cont'd)
EC-3447