2001 NISSAN PICK-UP sensor

Normal control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Crankshaft position sensor (TDC) Engine speed
Fuel injection con-
trol (Normal con-
trol)Electronic control fuel injec-
tion pump Accelerator position sensor Accelerator position
Vehicle speed sensor Vehicle speed
The amount of fuel injected under normal driving conditions is
determined according to sensor signals. The crankshaft position
sensor (TDC) detects engine speed and the accelerator position
sensor detects accelerator position. These sensors send signals
to the ECM.
The fuel injection data, predetermined by correlation between
various engine speeds and accelerator positions, are stored in
the ECM memory, forming a map. The ECM determines the
optimal amount of fuel to be injected using the sensor signals in
comparison with the map.
Maximum amount control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Engine coolant temperature sensor Engine coolant temperature
Fuel injection con-
trol (Maximum
amount control)Electronic control fuel injec-
tion pump Crankshaft position sensor (TDC) Engine speed
Accelerator position sensor Accelerator position
The maximum injection amount is controlled to an optimum by the engine speed, intake air amount, engine
coolant temperature, and accelerator opening in accordance with the driving conditions.
This prevents the oversupply of the injection amount caused by decreased air density at a high altitude or
during a system failure.
Deceleration control
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Accelerator position switch Accelerator positionFuel injection con-
trol (Deceleration
control)Electronic control fuel injec-
tion pump
Crankshaft position sensor (TDC) Engine speed
The ECM sends a fuel cut signal to the electronic control fuel injection pump during deceleration for better
fuel efficiency. The ECM determines the time of deceleration according to signals from the accelerator posi-
tion switch and crankshaft position sensor (TDC).
SEF649S
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
Fuel Injection Control System (Cont'd)
EC-3412

Fuel Injection Timing Control System
DESCRIPTION
The target fuel injection timing in accordance with the engine speed and the fuel injection amount are
recorded as a map in the ECM beforehand. The ECM and the injection pump control unit exchange signals
and perform feedback control for optimum injection timing in accordance with the map.
Air Conditioning Cut Control
DESCRIPTION
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Air conditioner switch Air conditioner ªONº signal
Air conditioner cut
controlAir conditioner relay Accelerator position sensor Accelerator position
Vehicle speed sensor Vehicle speed
Engine coolant temperature sensor Engine coolant temperature
System description
This system improves acceleration when the air conditioner is used.
When the accelerator pedal is fully depressed, the air conditioner is turned off for a few seconds.
When engine coolant temperature becomes excessively high, the air conditioner is turned off. This contin-
ues until the engine coolant temperature returns to normal.
Fuel Cut Control (at no load & high engine
speed)
DESCRIPTION
Input/output signal chart
Sensor Input Signal to ECM ECM Function Actuator
Vehicle speed sensor Vehicle speed
Fuel cut controlElectronic control fuel injec-
tion pump Park/Neutral position (PNP) switch Neutral position
Accelerator position switch Accelerator position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (TDC) Engine speed
If the engine speed is above 2,700 rpm with no load (for example, in neutral and engine speed over 2,700
rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies based on engine speed.
Fuel cut will operate until the engine speed reaches 1,500 rpm, then fuel cut is cancelled.
NOTE:
This function is different from deceleration control listed under ªFuel Injection Control Systemº,
EC-3411.
ENGINE AND EMISSION BASIC CONTROL SYSTEM
DESCRIPTIONYD25DDTi
EC-3413

2. Bleed air of the fuel filter. Refer to EC-3426.
Accelerator Position Sensor Idle Position
Learning
DESCRIPTION
ªAccelerator Position Sensor Idle Position Learningº is an opera-
tion to clear the self-learning fully closed accelerator position.
It must be performed each time harness connector of accelera-
tor position sensor or ECM is disconnected.
OPERATION PROCEDURE
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªOFF ACCEL PO SIGº in ªACTIVE TESTº mode with
CONSULT-II.
3. Touch ªCLEARº.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Let engine idle for 10 minutes.
BASIC SERVICE PROCEDUREYD25DDTi
EC-3427

ENGINE CONTROL COMPONENT PARTS/CONTROL
SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
SELF-DIAG
RESULTSDATA MONI-
TORACTIVE
TEST
ENGINE CONTROL COMPONENT PARTS
INPUTEngine coolant temperature sensor X X
Intake air temperature sensor X X
Vehicle speed sensor X X
Accelerator position sensor X X X
Accelerator position switch X X
Crankshaft position sensor (TDC) X X
Ignition switch (start signal) X
Park/Neutral position (PNP) switch X
Battery voltage X
Air conditioner switch X
Brake pedal position switch X X
Charge air pressure sensor X X
Heat up switch X
Stop lamp switch X X
OUTPUTGlow relayXX
EGR volume control valve X X X
Cooling fan relay X X X
Air conditioner relay X
X: Applicable
SELF-DIAGNOSTIC MODE
Regarding items detected in ªSELF-DIAG RESULTSº mode,
refer to ªTROUBLE DIAGNOSIS Ð INDEXº, EC-3400.
DATA MONITOR MODE
Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
CKPSzRPM (TDC)
[rpm]jj+The engine speed computed from the
crankshaft position sensor (TDC) signal
is displayed.
CMPSzRPMzPUMP
[rpm]jj+The engine speed computed from the
pulse signal sent from electronic control
fuel injection pump is displayed.
COOLAN TEMP/S
[ÉC] or [ÉF]
jj+The engine coolant temperature (deter-
mined by the signal voltage of the
engine coolant temperature sensor) is
displayed.+When the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the ECM
is displayed.
VHCL SPEED SE
[km/h] or [mph]jj+The vehicle speed computed from the
vehicle speed sensor signal is displayed.
FUEL TEMP SEN
[ÉC] or [ÉF]jj+The fuel temperature (sent from elec-
tronic control fuel injection pump) is dis-
played.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD25DDTi
CONSULT-II (Cont'd)
EC-3435

Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
ACCEL POS SEN [V]
jj+The accelerator position sensor signal
voltage is displayed.
FULL ACCEL SW
[ON/OFF]jj+Indicates [ON/OFF] condition from the
accelerator position switch signal.
OFF ACCEL SW
[ON/OFF]jj+Indicates [ON/OFF] condition from the
accelerator position switch signal.
SPILL/V [ÉCA]
j+The control position of spill valve (sent
from electronic control fuel injection
pump) is displayed.
BATTERY VOLT [V]
jj+The power supply voltage of ECM is dis-
played.
I/C INT/A T/S [V]
jj+The signal voltage of the intake air tem-
perature sensor is displayed.
P/N POSI SW
[ON/OFF]jj+Indicates [ON/OFF] condition from the
park/neutral position switch signal.
START SIGNAL
[ON/OFF]jj+Indicates [ON/OFF] condition from the
starter signal.+After starting the engine, [OFF] is dis-
played regardless of the starter signal.
AIR COND SIG
[ON/OFF]jj+Indicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
BRAKE SW [ON/OFF]
jj+Indicates [ON/OFF] condition from the
stop lamp switch signal.
BRAKE SW2
[ON/OFF]jj+Indicates [ON/OFF] condition from the
brake pedal position switch.
IGN SW
[ON/OFF]jj+Indicates [ON/OFF] condition from igni-
tion switch signal.
WARM UP SW
[ON/OFF]j+Indicates [ON/OFF] condition from the
heat up switch signal.
TURBO BST SEN
[kPa]j+The charge air pressure (determined by
the signal voltage sent to the ECM) is
displayed.
DECELER F/CUT
[ON/OFF]j+The [ON/OFF] condition from decelera-
tion fuel cut signal (sent from ECM) is
displayed.
INJ TIMG C/V [%]
j+The duty ratio of fuel injection timing
control valve (sent from electronic con-
trol fuel injection pump) is displayed.
AIR COND RLY
[ON/OFF]j+Indicates the control condition of the air
conditioner relay (determined by ECM
according to the input signals).
GLOW RLY [ON/OFF]
j+The glow relay control condition (deter-
mined by ECM according to the input
signal) is displayed.
COOLING FAN
[ON/OFF]
j+Indicates the control condition of the
cooling fans (determined by ECM
according to the input signal).
+ON ... Operates.
OFF ... Stopped.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD25DDTi
CONSULT-II (Cont'd)
EC-3436

Monitored item
[Unit]ECM
input
signalsMain
signalsDescription Remarks
EGR VOL CON/V
[step]
j+Indicates the EGR volume control value
computed by the ECM according to the
input signals.
+The opening becomes larger as the
value increases.
BARO SEN [kPa]
j+The barometric pressure (determined by
the signal voltage from the barometric
pressure sensor built into the ECM) is
displayed.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
COOLING FAN+Ignition switch: ON
+Turn cooling fan ªONº and ªOFFº
using CONSULT-II.Cooling fan moves and stops.+Harness and connector
+Cooling fan motor
+Cooling fan relay
OFF ACCEL PO
SIG+Clears the self-learning fully closed accelerator position, detected by accelerator position sensor, from the
ECM.
GLOW RLY+Ignition switch: ON (Engine
stopped)
+Turn the glow relay ªONº and
ªOFFº using CONSULT-II and
listen to operating sound.Glow relay makes the operating
sound.+Harness and connector
+Glow relay
INJ TIMING*1+Engine: Return to the original
trouble condition
+Retard the injection timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.+Electronic control fuel injection
pump
EGR VOL CONT/V+Ignition switch: ON
+Change EGR volume control
valve opening step using CON-
SULT-II.EGR volume control valve makes
an operating sound.+Harness and connector
+EGR volume control valve
*1: When using this item, DTC 0707 ªP7zF/INJ TIMG FBº may be detected. If so, erase it because it is not a malfunction.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONYD25DDTi
CONSULT-II (Cont'd)
EC-3437

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

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