Basic InspectionNCEC0038Precaution:
Perform Basic Inspection without electrical or mechanical loads applied;
IHeadlamp switch is OFF,
IOn vehicles equipped with daytime running light systems, set lighting switch to the 1st position to light only
small lamps.
IAir conditioner switch is OFF,
IRear window defogger switch is OFF,
ISteering 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, or the current need for scheduled maintenance.
2. Open engine hood and check the following:
IHarness connectors for improper connections
IVacuum hoses for splits, kinks, or improper connections
IWiring for improper connections, pinches, or cuts
IAir cleaner clogging
IHoses and ducts for leaks
SEF983U
©GO TO 2.
2 CHECK THROTTLE DRUM OPERATION
Confirm that throttle drum is in contact with stopper.
OK or NG
OK (With CONSULT-II)©GO TO 5.
OK (Without CONSULT-II)©GO TO 8.
NG©GO TO 3.
3 CHECK ACCELERATOR WIRE INSTALLATION
Check accelerator wire for slack.
OK or NG
OK©GO TO 4.
NG©Adjust accelerator wire. Refer to FE-section, ªAdjusting Accelerator Wireº.
4 CHECK THROTTLE VALVE OPERATION
1. Remove intake air ducts.
2. Check throttle valve operation when moving throttle drum by hand.
OK or NG
OK©Retighten the throttle drum fixing nuts.
NG©Clean the throttle body and throttle valve.
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONSR20DE
Basic Inspection
EC-84
18 CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªENG SPEEDº in ªDATA MONITORº mode with CONSULT-II.
3. Check idle speed.
750 50 rpm
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
750 50 rpm
OK or NG
OK©GO TO 20.
NG©GO TO 19.
19 CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of a problem, but this is rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to ªNATS (Nissan Anti-Theft System)º, EC-SR-
58.
©GO TO 14.
20 CHECK IGNITION TIMING
1. Start engine and warm it up to normal operating temperature.
2. Check ignition timing at idle using a timing light.
SEF984UIgnition timing:
15É 2É BTDC
OK or NG
OK©GO TO 28.
NG©GO TO 21.
21 CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-section.
OK or NG
OK©GO TO 19.
NG©1. Repair the timing chain installation.
2. GO TO 14.
Timing light
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONSR20DE
Basic Inspection (Cont'd)
EC-89
22 CHECK IGNITION TIMING
1. Start engine and let it idle.
2. Check ignition timing at idle using a timing light.
SEF984UIgnition timing:
15É 2É BTDC
OK or NG
OK©GO TO 28.
NG©GO TO 23.
23 PERFORM IDLE AIR VOLUME LEARNING
Refer to ªIdle Air Volume Learningº, EC-SR-46
Which is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©GO TO 24.
INCMP©GO TO 23.
24 CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªENG SPEEDº in ªDATA MONITORº mode with CONSULT-II.
3. Check idle speed.
750 50 rpm
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
750 50 rpm
OK or NG
OK©GO TO 26.
NG©GO TO 15.
25 CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function.
(ECM may be the cause of a problem, but this is rarely the case.)
2. Perform initialization of NATS system and registration of NATS ignition key IDs. Refer to ªNATS (Nissan Anti-Theft System)º,
EC-SR-58.
©GO TO 23.
26 CHECK IGNITION TIMING AGAIN
Check ignition timing again. Refer to Test No. 22.
OK or NG
OK©GO TO 28.
NG©GO TO 27.
Timing light
TROUBLE DIAGNOSIS Ð BASIC INSPECTIONSR20DE
Basic Inspection (Cont'd)
EC-90
Fail-safe ChartNCEC0040The ECM enters fail-safe mode if any of the following malfunctions is detected due to the open or short cir-
cuit. When the ECM enters the fail-safe mode, the MI illuminates.
DTC No.
Detected items Engine operating condition in fail-safe mode CON-
SULT-II
GSTECM*1
P0100 0100 Mass air flow sensor
circuitEngine speed will not rise more than 2,400 rpm due to the fuel cut.
P0115 0115 Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time
after turning ignition switch ªONº or ªSTARTº.
CONSULT-II displays the engine coolant temperature decided by ECM.
The radiator fan operates.
ConditionEngine coolant temperature decided (CON-
SULT-II display)
Just as ignition switch is
turned ON or Start40ÉC (104ÉF)
More than approx. 4 minutes
after ignition ON or Start80ÉC (176ÉF)
Except as shown above40 - 80ÉC (104 - 176ÉF)
(Depends on the time)
P0120 0120 Throttle position sensor
circuitThrottle position will be determined based on the injected fuel amount and
the engine speed. Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
Unable to
access
ECMUnable to
access
Diagnostic
Test Mode
IIECMECM fail-safe activating condition
The computing function of the ECM was judged to be malfunctioning.
When the fail-safe system activates (i.e., if the ECM detects a malfunction
condition in the CPU of ECM), the MI on the instrument panel lights to warn
the driver.
However it is not possible to access ECM and DTC cannot be confirmed.
Engine control with fail-safe
When ECM fail-safe is operating, fuel injection, ignition timing, fuel pump
operation and IACV-AAC valve operation are controlled under certain limita-
tions.
ECM fail-safe operation
Engine speedEngine speed will not rise more than
3,000 rpm
Fuel injection Simultaneous multiport fuel injection system
Ignition timing Ignition timing is fixed at the preset valve
Fuel pumpFuel pump relay is ªONº when engine is
running and ªOFFº when engine stalls
IACV-AAC valve Full open
Replace ECM, if ECM fail-safe condition is confirmed.
*: In Diagnostic Test Mode II (Self-diagnostic results)
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONSR20DE
Fail-safe Chart
EC-93
CONSULT-II Reference Value in Data Monitor
Mode
NCEC0042Remarks:
ISpecification data are reference values.
ISpecification data are output/input values which are detected or supplied by the ECM at the connector.
* Specification data may not be directly related to their components signals/values/operations.
(i.e., Adjust ignition timing with a timing light before monitoring IGN TIMING. Specification data might be displayed even when igni-
tion timing is not adjusted to specification. This IGN TIMING monitors the data calculated by the ECM according to the input signals
from the camshaft position sensor and other ignition timing related sensors.)
IIf the real-time diagnosis results are NG, and the on board diagnostic system results are OK, when diagnosing the mass air flow sensor,
first check to see if the fuel pump control circuit is normal.
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEEDITachometer: Connect
IRun engine and compare tachometer indication with the CONSULT-II
value.Almost the same speed as the
CONSULT-II value.
MAS A/F SE -B1IEngine: After warming up
IAir conditioner switch: OFF
IShift lever: ªNº
INo-loadIdle 1.0 - 1.7V
2,500 rpm 1.5 - 2.4V
COOLAN TEMP/SIEngine: After warming up More than 70ÉC (158ÉF)
HO2S1 (B1)
IEngine: After warming upMaintaining engine speed at 2,000
rpm0 - 0.3V+,0.6 - 1.0V
HO2S1 MNTR (B1)LEAN+,RICH
Changes more than 5 times
during 10 seconds.
HO2S2 (B1)
IEngine: After warming upRevving engine from idle to 3,000
rpm quickly0 - 0.3V+,0.6 - 1.0V
HO2S2 MNTR (B1)LEAN+,RICH
VHCL SPEED SEITurn drive wheels and compare speedometer indication with the CON-
SULT-II valueAlmost the same speed as the
CONSULT-II value
BATTERY VOLTIIgnition switch: ON (Engine stopped) 11 - 14V
THRTL POS SENIEngine is idling Throttle valve fully closed 0.35 - 0.65V
IIgnition switch: ON
(Engine stopped)Throttle valve fully opened 3.5 - 4.5V
START SIGNALIIgnition switch: ON,START,ON OFF,ON,OFF
CLSD THL/P SW
CLSD THL POSIEngine: IdleThrottle valve: Idle position ON
Throttle valve: Slightly open OFF
AIR COND SIGIEngine: After warming up, idle
the engineA/C switch ªOFFº OFF
A/C switch ªONº
(Compressor operates)ON
P/N POSI SWIIgnition switch: ONShift lever ªPº or ªNº ON
Except above OFF
PW/ST SIGNALIEngine: After warming up, idle
the engineSteering wheel in neutral position
(forward direction)OFF
The steering wheel is fully turned ON
IGNITION SWIIgnition switch: ON,OFF ON,OFF
INJ PULSE -B1IEngine: After warming up
IAir conditioner switch: OFF
IShift lever: ªNº
INo-loadIdle 2.4 - 3.2 msec
2,000 rpm 1.9 - 2.8 msec
HEATER FAN SWIIgnition switch: ONHeater fan switch: ON ON
Heater fan switch: OFF OFF
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONSR20DE
CONSULT-II Reference Value in Data Monitor Mode
EC-98
DescriptionNLEC1748The specification (SP) value indicates the tolerance of the value that is displayed in ªDATA MONITOR (SPEC)º
mode of CONSULT-II during normal operation of the Engine Control System. When the value in ªDATA MONI-
TOR (SPEC)º mode is within the SP value, the Engine Control System is confirmed OK. When the value in
ªDATA MONITOR (SPEC)º mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
IB/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)
IA/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
IMAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionNLEC1749IVehicle driven distance: More than 5,000 km (3,107 miles)
IBarometric pressure: 98.3 - 104.3 kPa (0.983 - 1.043 bar, 1.003 - 1.064 kg/cm2, 14.25 - 15.12 psi)
IAtmospheric temperature: 20 - 30ÉC (68 - 86ÉF)
IEngine coolant temperature: 75 - 95ÉC (167 - 203ÉF)
ITransmission: Warmed-up*1
IElectrical load: Not applied*2
IEngine speed: Idle
*1: For after the engine is warmed up to normal operating temperature, drive vehicle until ªFLUID TEMP SEº
(CVT fluid temperature sensor signal) indicates less than 0.9V.
*2: Rear window defogger switch, air conditioner switch, lighting switch are ªOFFº. Cooling fans are not oper-
ating. Steering wheel is straight ahead.
SEF601Z
Inspection ProcedureNLEC1750NOTE:
Perform ªDATA MONITOR (SPEC)º mode in maximum scale dis-
play.
1. Perform ªBasic Inspectionº, EC-84.
2. Confirm that the testing conditions indicated above are met.
3. Select ªB/FUEL SCHDLº, ªA/F ALPHA-B1º and ªMAS A/F
SE-B1º in ªDATA MONITOR (SPEC)º mode with CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go to ªDiagnostic Procedureº, EC-111.
TROUBLE DIAGNOSIS Ð SPECIFICATION VALUESR20DE
Description
EC-110
Component DescriptionNCEC0050The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. It consists of a hot wire that is supplied with electric
current from the ECM. The temperature of the hot wire is controlled
by the ECM a certain amount. The heat generated by the hot wire
is reduced as the intake air flows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot wire as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
NCEC0051Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE -B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 1.0 - 1.7V
2,500 rpm 1.5 - 2.4V
CAL/LD VALUEIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle Not used
2,500 rpm Not used
MASS AIRFLOWIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.5 - 5.0 g×m/s
2,500 rpm 7.1 - 12.5 g×m/s
ECM Terminals and Reference ValueNCEC0052Specification data are reference values and are measured between each terminal and 48 (ECM ground).
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
61 B Mass air flow sensor[Engine is running]
IWarm-up condition
IIdle speed1.3 - 1.7V
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm1.8 - 2.4V
73 WMass air flow sensor
ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
On Board Diagnosis LogicNCEC0053
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0100*
0100A) An excessively high voltage from the sensor is sent to
ECM when engine is not running.IHarness or connectors
(The sensor circuit is open or shorted.)
IMass air flow sensor
B) An excessively low voltage from the sensor is sent to
ECM when engine is running.IHarness or connectors
(The sensor circuit is open or shorted.)
IIntake air leaks
IMass air flow sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
SEF987W
DTC P0100 MASS AIR FLOW SENSOR (MAFS)SR20DE
Component Description
EC-120
Component DescriptionNCEC0072The engine coolant temperature sensor is used to detect the
engine coolant temperature. The sensor modifies a voltage signal
from the ECM. The modified signal returns to the ECM as the
engine coolant temperature input. The sensor uses a thermistor
which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature increases.
Engine coolant temperature
ÉC (ÉF)Voltage*
VResistance
kW
þ10 (14)4.4 7.0 - 11.4
20 (68)3.5 2.1 - 2.9
50 (122)2.2 0.68 - 1.00
90 (194)0.9 0.236 - 0.260
*: These data are reference values and are measured between ECM terminal 70
(Engine coolant temperature sensor) and ECM terminal 48 (ECM ground).
CONSULT-II Reference Value in Data Monitor
Mode
NCEC0073
MONITOR ITEM CONDITION SPECIFICATION
COOLAN TEMP/SIEngine: After warming up More than 70ÉC (158ÉF)
On Board Diagnosis LogicNCEC0074
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0115
0115IAn excessively high or low voltage from the sensor is
sent to ECM.*IHarness or connectors
(The sensor circuit is open or shorted.)
IEngine coolant temperature sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MI lights up.
Detected items Engine operating condition in fail-safe mode
Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning ignition switch
ªONº or ªSTARTº.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided (CONSULT-II
display)
Just as ignition switch is turned ON or Start 40ÉC (104ÉF)
More than approx. 4 minutes after ignition ON or
Start80ÉC (176ÉF)
Except as shown above40 - 80ÉC (104 - 176ÉF)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates
while the engine is running.
SEF594K
SEF012P
DTC P0115 ENGINE COOLANT TEMPERATURE SENSOR
(ECTS) (CIRCUIT)SR20DE
Component Description
EC-132