2001 INFINITI QX4 wiring diagram

Possible Cause ........................................................ 411
Overall Function Check ........................................... 411
DTC P0464 FUEL LEVEL SENSOR CIRCUIT...........413
Component Description ...........................................413
On Board Diagnostic Logic......................................413
Possible Cause ........................................................413
DTC Confirmation Procedure ..................................413
Wiring Diagram ........................................................414
Diagnostic Procedure ..............................................415
DTC P0500 VEHICLE SPEED SENSOR (VSS).........417
Component Description ...........................................417
ECM Terminals and Reference Value .....................417
On Board Diagnosis Logic.......................................417
Possible Cause ........................................................418
DTC Confirmation Procedure ..................................418
Overall Function Check ...........................................418
Wiring Diagram ........................................................420
Diagnostic Procedure ..............................................421
DTC P0505 IDLE AIR CONTROL VALVE (IACV) -
AUXILIARY AIR CONTROL (AAC) VALVE...............422
Description ...............................................................422
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................423
ECM Terminals and Reference Value .....................423
On Board Diagnosis Logic.......................................423
Possible Cause ........................................................423
DTC Confirmation Procedure ..................................423
Wiring Diagram ........................................................425
Diagnostic Procedure ..............................................426
DTC P0510 CLOSED THROTTLE POSITION
SWITCH.......................................................................431
Component Description ...........................................431
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................431
ECM Terminals and Reference Value .....................431
On Board Diagnosis Logic.......................................431
Possible Cause ........................................................431
DTC Confirmation Procedure ..................................432
Overall Function Check ...........................................432
Wiring Diagram ........................................................434
Diagnostic Procedure ..............................................435
DTC P0600 A/T COMMUNICATION LINE..................440
System Description ..................................................440
ECM Terminals and Reference Value .....................440
On Board Diagnosis Logic.......................................440
Possible Cause ........................................................440
DTC Confirmation Procedure ..................................440
Wiring Diagram ........................................................442
Diagnostic Procedure ..............................................443
DTC P0605 ECM.........................................................444
Component Description ...........................................444
On Board Diagnosis Logic.......................................444Possible Cause ........................................................444
DTC Confirmation Procedure ..................................444
Diagnostic Procedure ..............................................445
DTC P1110 (RIGHT, -B1), P1135 (LEFT, -B2)
INTAKE VALVE TIMING CONTROL..........................446
Description ...............................................................446
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................446
ECM Terminals and Reference Value .....................447
On Board Diagnosis Logic.......................................448
Possible Cause ........................................................448
DTC Confirmation Procedure ..................................449
D T C P 1111(RIGHT, -B1), P1136 (LEFT, -B2)
INTAKE VALVE TIMING CONTROL SOLENOID
VALVE (CIRCUIT)........................................................451
Component Description ...........................................451
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................451
ECM Terminals and Reference Value .....................451
On Board Diagnosis Logic.......................................452
Possible Cause ........................................................452
DTC Confirmation Procedure ..................................452
Wiring Diagram ........................................................453
Diagnostic Procedure ..............................................455
DTC P1130 SWIRL CONTROL VALVE CONTROL
SOLENOID VALVE......................................................458
Description ...............................................................458
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................459
ECM Terminals and Reference Value .....................459
On Board Diagnosis Logic.......................................459
Possible Cause ........................................................460
DTC Confirmation Procedure ..................................460
Wiring Diagram ........................................................462
Diagnostic Procedure ..............................................463
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2)
INTAKE VALVE TIMING CONTROL POSITION
SENSOR (CIRCUIT)....................................................482
Component Description ...........................................482
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................482
ECM Terminals and Reference Value .....................482
On Board Diagnosis Logic.......................................483
Possible Cause ........................................................483
DTC Confirmation Procedure ..................................483
Wiring Diagram ........................................................485
Diagnostic Procedure ..............................................487
DTC P1148 (RIGHT BANK, -B1), P1168 (LEFT
BANK, -B2) CLOSED LOOP CONTROL...................491
On Board Diagnosis Logic.......................................491
Possible Cause ........................................................491
DTC Confirmation Procedure ..................................491GI
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CONTENTS(Cont'd)
EC-5

Overall Function Check ...........................................492
Diagnostic Procedure ..............................................492
DTC P1165 SWIRL CONTROL VALVE CONTROL
VACUUM CHECK SWITCH.........................................493
Component Description ...........................................493
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................493
ECM Terminals and Reference Value .....................493
On Board Diagnosis Logic.......................................494
Possible Cause ........................................................494
DTC Confirmation Procedure ..................................494
Wiring Diagram ........................................................495
Diagnostic Procedure ..............................................496
DTC P1320 IGNITION SIGNAL...................................499
Component Description ...........................................499
ECM Terminals and Reference Value .....................499
On Board Diagnosis Logic.......................................499
Possible Cause ........................................................500
DTC Confirmation Procedure ..................................500
Wiring Diagram ........................................................501
Diagnostic Procedure ..............................................504
DTC P1335 CRANKSHAFT POSITION SENSOR
(CKPS) (REF)..............................................................510
Component Description ...........................................510
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................510
ECM Terminals and Reference Value .....................510
On Board Diagnosis Logic....................................... 511
Possible Cause ........................................................ 511
DTC Confirmation Procedure .................................. 511
Wiring Diagram ........................................................513
Diagnostic Procedure ..............................................514
DTC P1336 CRANKSHAFT POSITION SENSOR
(CKPS) (POS) (COG)..................................................517
Component Description ...........................................517
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................517
ECM Terminals and Reference Value .....................518
On Board Diagnosis Logic.......................................518
Possible Cause ........................................................518
DTC Confirmation Procedure ..................................519
Wiring Diagram ........................................................520
Diagnostic Procedure ..............................................521
DTC P1441 EVAP CONTROL SYSTEM (VERY
SMALL LEAK).............................................................526
On Board Diagnosis Logic.......................................526
Possible Cause ........................................................526
DTC Confirmation Procedure ..................................527
Diagnostic Procedure ..............................................529
DTC P1444 EVAP CANISTER PURGE VOLUME
CONTROL SOLENOID VALVE...................................541
Description ...............................................................541CONSULT-II Reference Value in Data Monitor
Mode ........................................................................541
ECM Terminals and Reference Value .....................542
On Board Diagnosis Logic.......................................542
Possible Cause ........................................................542
DTC Confirmation Procedure ..................................543
Wiring Diagram ........................................................544
Diagnostic Procedure ..............................................545
DTC P1446 EVAPORATIVE EMISSION (EVAP)
CANISTER VENT CONTROL VALVE (CLOSE).........553
Component Description ...........................................553
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................553
ECM Terminals and Reference Value .....................553
On Board Diagnosis Logic.......................................553
Possible Cause ........................................................554
DTC Confirmation Procedure ..................................554
Wiring Diagram ........................................................555
Diagnostic Procedure ..............................................556
DTC P1447 EVAPORATIVE EMISSION (EVAP)
CONTROL SYSTEM PURGE FLOW
MONITORING..............................................................561
System Description ..................................................561
On Board Diagnosis Logic.......................................561
Possible Cause ........................................................561
DTC Confirmation Procedure ..................................562
Overall Function Check ...........................................563
Diagnostic Procedure ..............................................564
DTC P1448 EVAPORATIVE EMISSION (EVAP)
CANISTER VENT CONTROL VALVE (OPEN)...........573
Component Description ...........................................573
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................573
ECM Terminals and Reference Value .....................573
On Board Diagnosis Logic.......................................573
Possible Cause ........................................................574
DTC Confirmation Procedure ..................................574
Overall Function Check ...........................................575
Wiring Diagram ........................................................576
Diagnostic Procedure ..............................................577
DTC P1464 FUEL LEVEL SENSOR CIRCUIT
(GROUND SIGNAL)....................................................582
Component Description ...........................................582
On Board Diagnostic Logic......................................582
Possible Cause ........................................................582
DTC Confirmation Procedure ..................................582
Wiring Diagram ........................................................583
Diagnostic Procedure ..............................................584
DTC P1490 VACUUM CUT VALVE BYPASS
VALVE (CIRCUIT)........................................................585
Description ...............................................................585
CONTENTS(Cont'd)
EC-6

CONSULT-II Reference Value in Data Monitor
Mode ........................................................................585
ECM Terminals and Reference Value .....................585
On Board Diagnosis Logic.......................................586
Possible Cause ........................................................586
DTC Confirmation Procedure ..................................586
Wiring Diagram ........................................................587
Diagnostic Procedure ..............................................588
DTC P1491 VACUUM CUT VALVE BYPASS
VALVE..........................................................................591
Description ...............................................................591
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................591
ECM Terminals and Reference Value .....................591
On Board Diagnosis Logic.......................................592
Possible Cause ........................................................592
DTC Confirmation Procedure ..................................592
Overall Function Check ...........................................593
Wiring Diagram ........................................................594
Diagnostic Procedure ..............................................595
DTC P1605 A/T DIAGNOSIS COMMUNICATION
LINE.............................................................................603
Component Description ...........................................603
On Board Diagnosis Logic.......................................603
Possible Cause ........................................................603
DTC Confirmation Procedure ..................................603
DTC P1706 PARK/NEUTRAL POSITION (PNP)
SWITCH.......................................................................604
Component Description ...........................................604
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................604
ECM Terminals and Reference Value .....................604
On Board Diagnosis Logic.......................................604
Possible Cause ........................................................604
DTC Confirmation Procedure ..................................605
Overall Function Check ...........................................606
Wiring Diagram ........................................................607
Diagnostic Procedure ..............................................608
VARIABLE INDUCTION AIR CONTROL SYSTEM
(VIAS)...........................................................................610
Description ...............................................................610
ECM Terminals and Reference Value ..................... 611
Wiring Diagram ........................................................612
Diagnostic Procedure ..............................................613
INJECTOR...................................................................616
Component Description ...........................................616
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................616
ECM Terminals and Reference Value .....................616
Wiring Diagram ........................................................617Diagnostic Procedure ..............................................618
START SIGNAL...........................................................621
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................621
ECM Terminals and Reference Value .....................621
Wiring Diagram ........................................................622
Diagnostic Procedure ..............................................623
FUEL PUMP.................................................................625
System Description ..................................................625
Component Description ...........................................625
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................625
ECM Terminals and Reference Value .....................626
Wiring Diagram ........................................................627
Diagnostic Procedure ..............................................628
POWER STEERING OIL PRESSURE SWITCH.........634
Component Description ...........................................634
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................634
ECM Terminals and Reference Value .....................634
Wiring Diagram ........................................................635
Diagnostic Procedure ..............................................636
REFRIGERANT PRESSURE SENSOR......................639
Description ...............................................................639
ECM Terminals and Reference Value .....................639
Wiring Diagram ........................................................640
Diagnostic Procedure ..............................................641
ELECTRICAL LOAD SIGNAL.....................................643
ECM Terminals and Reference Value .....................643
Wiring Diagram ........................................................644
Diagnostic Procedure ..............................................645
MIL & DATA LINK CONNECTORS............................648
Wiring Diagram ........................................................648
SERVICE DATA AND SPECIFICATIONS (SDS).......649
Fuel Pressure Regulator..........................................649
Idle Speed and Ignition Timing ................................649
Mass Air Flow Sensor..............................................649
Engine Coolant Temperature Sensor ......................649
Heated Oxygen Sensor 1 Heater (Front) ................649
Fuel Pump ...............................................................649
IACV-AAC Valve ......................................................649
Injector .....................................................................649
Resistor ....................................................................649
Throttle Position Sensor ..........................................650
Calculated Load Value.............................................650
Intake Air Temperature Sensor ................................650
Heated Oxygen Sensor 2 Heater (Rear).................650
Crankshaft Position Sensor (REF) ..........................650
Fuel Tank Temperature Sensor ...............................650
Camshaft Position Sensor (PHASE) .......................650GI
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CONTENTS(Cont'd)
EC-7

SEF348N
IWhen measuring ECM signals with a circuit tester, never
allow the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
IDo not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the
ECM's transistor. Use a ground other than the ECM
terminals, such as the ground.
SEF099WB
IRegarding model R50, ª-B1º indicates the right bank and
ª-B2º indicates the left bank as shown in the figure.
IBank 1 includes No. 1 cylinder.
Wiring Diagrams and Trouble DiagnosisNBEC0006When you read Wiring diagrams, refer to the following:
IGI-34, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnosis, refer to the following:
IGI-38, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSISº
IGI-34, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
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PRECAUTIONS
Precautions (Cont'd)
EC-17

25 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Maintaining engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 63 and ground.
6. Make sure that the voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000
rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©INSPECTION END
NG©GO TO 26.
26 DETECT MALFUNCTIONING PART
Check the following.
ICheck fuel pressure regulator. Refer to EC-40.
ICheck mass air flow sensor and its circuit. Refer to EC-150.
ICheck injector and its circuit. Refer to EC-616.
Clean or replace if necessary.
ICheck engine coolant temperature sensor and its circuit. Refer to EC-187.
ICheck ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
27 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 1) harness connector.
4. Check harness continuity between ECM terminal 63 and heated oxygen sensor 1 (front) RH harness connector terminal
1.
Refer to Wiring Diagram, EC-196.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-53

28 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 2) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 2) harness connector.
4. Check harness continuity between ECM terminal 62 and front heated oxygen sensor LH harness connector terminal 1.
Refer to Wiring Diagram, EC-197.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
29 REPAIR OR REPLACE
Repair or replace harness between ECM and heated oxygen sensor 1 (front).
©GO TO 3.
30 PREPARATION FOR ªCOº % CHECK
With CONSULT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº.
3. Select ªENG COOLANT TEMPº in ªACTIVE TESTº mode.
4. Set ªENG COOLANT TEMPº to 5ÉC (41ÉF) by touching ªDOWNº and ªQdº.
SEF172Y
Without CONSULT-II
1. Disconnect ECM harness connector.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
SEF982UA
©GO TO 31.
BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-54

Main Power Supply and Ground Circuit
WIRING DIAGRAMNBEC0047
MEC940C
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit
EC-142

DIAGNOSTIC PROCEDURENBEC0049
1 INSPECTION START
Start engine.
Is engine running?
YesorNo
Ye s©GO TO 9.
No©GO TO 2.
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªOFFº and then ªONº.
2. Check voltage between ECM terminal 43 and ground with CONSULT-II or tester.
SEF291X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
I10A fuses
IHarness connectors M33, F22
IHarness for open or short between ECM and ignition switch
©Repair harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.
Refer to WIRING DIAGRAM.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-144