2001 INFINITI QX4 IDX

17 ADJUSTMENT THROTTLE POSITION SWITCH CLOSED POSITION-II
1. Temporarily tighten sensor body fixing bolts as follows.
IGradually move the sensor body clockwise and stop it when the continuity comes to exist, then temporarily
tighten sensor body fixing bolts.
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2. Make sure two or three times that the continuity exists when the throttle valve is closed and continuity does not exist
when it is opened.
3. Remove 0.05 mm (0.0020 in) feeler gauge then insert 0.15 mm (0.0059 in) feeler gauge.
4. Make sure two or three times that the continuity does not exist when the throttle valve is closed.
5. Tighten throttle position sensor.
6. Check the continuity again.
Continuity does not exist while closing the throttle valve.
OK or NG
OK©GO TO 18.
NG©GO TO 16.
18 RESET THROTTLE POSITION SENSOR IDLE POSITION MEMORY
NOTE:
Always warm up engine to normal operating temperature. If engine is cool, the throttle position sensor idle posi-
tion memory will not be reset correctly.
1. Confirm that proper vacuum is applied. Refer to Test No. 10.
2. Attach blind cap to vacuum port from which vacuum hose to throttle opener was disconnected.
3. Start engine.
4. Warm up engine to normal operating temperature.
5. Stop engine. (Turn ignition switch ªOFFº.)
6. Turn ignition switch ªONº and wait at least 5 seconds.
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7. Turn ignition switch ªOFFº and wait at least 10 seconds.
8. Repeat steps 6 and 7, 20 times.
©GO TO 19.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-111

23 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 (in ªPº or ªNº position)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
750±50 rpm (in ªPº or ªNº position)
OK or NG
OK©GO TO 28.
NG©GO TO 24.
24 REPLACE IACV-AAC VALVE
Replace IACV-AAC valve.
©GO TO 25.
25 PERFORM IDLE AIR VOLUME LEARNING
Refer to ªIdle Air Volume Learningº, EC-57.
Which is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©GO TO 26.
INCMP©1. Follow the construction of ªIdle Air Volume Learningº.
2. GO TO 22.
26 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 (in ªPº or ªNº position)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
750±50 rpm (in ªPº or ªNº position)
OK or NG
OK©GO TO 28.
NG©GO TO 27.
27 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 IVIS (NATS) system and registration of IVIS (NATS) ignition key IDs. Refer to ªIVIS (INFINITI
VEHICLE IMMOBILIZER SYSTEM Ð NATS)º, EC-74.
©GO TO 22.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-113

31 PERFORM IDLE AIR VOLUME LEARNING
Refer to ªIdle Air Volume Learningº, EC-57.
Which is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©GO TO 32.
INCMP©1. Follow the construction of ªIdle Air volume Learningº.
2. GO TO 31.
32 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 (in ªPº or ªNº position)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
750±50 rpm (in ªPº or ªNº position)
OK or NG
OK©GO TO 34.
NG©GO TO 33.
33 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 NVIS (NATS) system and registration of NVIS (NATS) ignition key IDs. Refer to ªNVIS (NISSAN
VEHICLE IMMOBILIZER SYSTEM Ð NATS)º, EC-74.
©GO TO 31.
34 CHECK IGNITION TIMING AGAIN
Check ignition timing again. Refer to Test No. 30.
OK or NG
OK©GO TO 36.
NG©GO TO 35.
35 CHECK TIMING CHAIN INSTALLATION
Check timing chain installation. Refer to EM-29, ªInstallationº.
OK or NG
OK©GO TO 33.
NG©1. Repair the timing chain installation.
2. GO TO 31.
36 ERASE UNNECESSARY DTC
After this inspection, unnecessary DTC No. might be displayed.
Erase the stored memory in ECM and TCM (Transmission control module).
Refer to ªHow to Erase Emission-Related Diagnostic Informationº, EC-72 and AT-35, ªHOW TO ERASE DTCº.
©INSPECTION END
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-115

Fail-safe Chart=NBEC0040The 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 MIL illuminates.
DTC No. Detected items Engine operating condition in fail-safe mode
P0100 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0115 Engine coolant temperature
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 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 Throttle position sensor cir-
cuitThrottle 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
P1335 Crankshaft position sensor
(REF) circuitCompression TDC signal (120É signal) is controlled by camshaft position sensor
(PHASE) signal and crankshaft position sensor (POS) signal. Ignition timing will be
delayed 0É to 2É.
Unable to
access ECMECMECM 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 condi-
tion in the CPU of ECM), the MIL 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,
IACV-AAC valve operation and cooling fan operation are controlled under certain
limitations.
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.
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Fail-safe Chart
EC-117

SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Engine
controlCrankshaft position sensor (REF)
circuit
22EC-510
Crankshaft position sensor (POS)
circuitEC-334, 517
Camshaft position sensor
(PHASE) circuit3EC-342
Mass air flow sensor circuit 1
122
222 2EC-150
Heated oxygen sensor 1 (front)
circuit
3EC-192
Engine coolant temperature sen-
sor circuit1 3 3 EC-169, 187
Throttle position sensor circuit 2 2 EC-174
Incorrect throttle position sensor
adjustment3 1 1 1 1 1 1 1 EC-101
Vehicle speed sensor circuit 2 3 3
3EC-417
Knock sensor circuit 2 EC-328
ECM 2233333 3 33EC-444, 117
Start signal circuit 2 EC-621
Park/Neutral position switch circuit 3 3
333 EC-604
Power steering oil pressure switch
circuit2 EC-634
Electrical load signal circuitEC-644
1 - 6: The numbers refer to the order of inspection.
(continued on next page)
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Matrix Chart (Cont'd)
EC-119

SYMPTOM
Reference
section
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Engine Cylinder head
55555 5 5 5
EM section Cylinder head gasket 4 3
Cylinder block
66666 6 6 64 Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Valve
mechanismTiming chain
55555 5 5 5 Camshaft
Intake valve
3
Exhaust valve
Exhaust Exhaust manifold/Tube/Muffler/
Gasket
5555555 5 FEsection
Three way catalyst
Lubrication Oil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery
55555 5 5 5MA, EM, LC
section
Oil level (Low)/Filthy oilLC section
Cooling Radiator/Hose/Radiator filler cap
55555 5 5 45 Thermostat 5
Water pump
Water gallery
Coolant level (low)/Contaminated
coolantMA section
1 - 6: The numbers refer to the order of inspection.
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Matrix Chart (Cont'd)
EC-121

MONITOR ITEM CONDITION SPECIFICATION
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: After warming up, idle
the engineThrottle valve: fully closed 0.15 - 0.85V
IEngine: After warming up
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened 3.5 - 4.7V
START SIGNALIIgnition switch: ON,START,ON OFF,ON,OFF
CLSD THL POS
CLSD THL/P SWIEngine: After warming up, idle
the engineThrottle valve: Idle position ON
Throttle valve: Slightly open OFF
AIR COND SIGIEngine: After warming up, idle
the engineAir conditioner switch: ªOFFº OFF
Air conditioner 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 turned ON
IGNITION SWIIgnition switch: ON,OFF,ON ON,OFF,ON
INJ PULSE-B2
INJ PULSE-B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.4 - 3.2 msec
2,000 rpm 1.9 - 2.8 msec
B/FUEL SCHDLIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.0 - 3.2 msec
2,000 rpm 1.4 - 2.6 msec
IGN TIMINGIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 15ɱ5É BTDC
2,000 rpm More than 25É BTDC
IACV-AAC/VIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2 - 10 step
2,000 rpm Ð
PURG VOL C/VIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 0 %
2,000 rpm Ð
A/F ALPHA-B2
A/F ALPHA-B1IEngine: After warming upMaintaining engine speed at 2,000
rpm54 - 155%
EVAP SYS PRESIIgnition switch: ON Approx. 3.4V
AIR COND RLYIAir conditioner switch: OFF,ON OFF,ON
FUEL PUMP RLYIIgnition switch is turned to ON (Operates for 5 seconds)
IEngine running and crankingON
Except as shown above OFF
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
CONSULT-II Reference Value in Data Monitor Mode (Cont'd)
EC-123

SEF306Y
ENG SPEED, MAS A/F SE-B1, THRTL POS SEN, HO2S2 (B1), HO2S1 (B1), INJ PULSE-B1NBEC0043S02Below is the data for ªENG SPEEDº, ªMAS A/F SE-B1º, ªTHRTL POS SENº, ªHO2S2 (B1)º, ªHO2S1 (B1)º and
ªINJ PULSE-B1º when revving engine quickly up to 4,800 rpm under no load after warming up engine suffi-
ciently.
Each value is for reference, the exact value may vary.
SEF241Y
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Major Sensor Reference Graph in Data Monitor Mode (Cont'd)
EC-125