2001 INFINITI QX4 ignition

2 CHECK SYMPTOM
1. Apply brake.
2. Start engine.
Does the symptom appear only when engine is started?
Ye s©Carry out self-diagnosis. Refer to BR-41, 44.
No©Go to ª3. CHECK WARNING LAMP INDICATIONº in ª2. Unexpected Pedal Actionº,
BR-70.
NOTE:
ABS may operate and cause vibration under any of the following
conditions.
IApplying brake gradually when shifting or operating clutch.
ILow friction (slippery) road.
IHigh speed cornering.
IDriving over bumps and pot holes.
IEngine speed is over 5,000 rpm with vehicle stopped.
6. Warning Lamp Does Not Come On When
Ignition Switch Is Turned On
NBBR0112
1 INSPECTION START
Warning lamp circuit inspection
SBR673E
©GO TO 2.
2 CHECK FUSE
Check 10A fuse No. 8. For fuse layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fuse OK?
Ye s©GO TO 3.
No©Replace fuse.
TROUBLE DIAGNOSES FOR SYMPTOMSABS
5. Pedal Vibration and Noise (Cont'd)
BR-72

3 CHECK WARNING LAMP ACTIVATE
Disconnect ABS actuator and electric unit connector.
SBR672E
Does the warning lamp activate?
Ye s©Replace ABS actuator and electric unit.
No©GO TO 4.
4 CHECK HARNESS FOR SHORT
1. Disconnect ABS actuator and electric unit connector and combination meter connector M24.
2. Check continuity between ABS actuator and electric unit connector E111 (body side) terminal 10 (2WD) or 21 (4WD)
and ground.
SBR499E
Continuity should not exist.
Does continuity exist?
Ye s©Repair harness or connectors.
No©Check combination meter.
Refer to EL-114, ªWARNING LAMPSº.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
6. Warning Lamp Does Not Come On When Ignition Switch Is Turned On (Cont'd)
BR-73

7. Warning Lamp Stays On When Ignition
Switch Is Turned On
=NBBR0113
1 INSPECTION START
ABS control unit inspection
SBR674E
©GO TO 2.
2 CHECK FUSE
Check 7.5A fuse No. 7. For fuse layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fuse OK?
Ye s©GO TO 3.
No©GO TO 8.
3 CHECK HARNESS CONNECTOR
Check ABS actuator and electric unit pin terminals for damage or bad connection of ABS actuator and electric unit harness
connector. Reconnect ABS actuator and electric unit harness connector. Then retest.
Does warning lamp stay on when ignition switch is turned ON?
Ye s©GO TO 4.
No©INSPECTION END
4 CHECK ABS ACTUATOR AND ELECTRIC UNIT GROUND CIRCUIT
Refer to ªABS ACTUATOR AND ELECTRIC UNIT GROUNDº in ªGround Circuit Checkº, BR-53.
Is ground circuit OK?
Ye s©GO TO 5.
No©Repair harness or connector.
TROUBLE DIAGNOSES FOR SYMPTOMSABS
7. Warning Lamp Stays On When Ignition Switch Is Turned On
BR-74

5 CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUIT
1. Disconnect ABS actuator and electric unit connector.
2. Check voltage between ABS actuator and electric unit connector E111 (body side) terminal 15 and ground.
SBR495E
Does battery voltage exist when ignition switch is turned ON?
Ye s©GO TO 6.
No©Check the following.
If NG, repair harness or connector.
IHarness connector E111
IHarness for open or short between ABS actuator and electric unit and fuse
6 CHECK WARNING LAMP
1. Disconnect ABS actuator and electric unit connector.
2. Connect suitable wire between ABS actuator and electric unit connector E111 (body side) terminal 10 (2WD) or 21
(4WD) and ground.
SBR502E
Does the warning lamp deactivate?
Ye s©Replace ABS actuator and electric unit.
No©GO TO 7.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
7. Warning Lamp Stays On When Ignition Switch Is Turned On (Cont'd)
BR-75

7 CHECK ABS WARNING LAMP CONTROL CIRCUIT FOR OPEN
1. Disconnect combination meter connector M24.
2. Check continuity between combination meter connector M24 (body side) terminal 10 and ABS actuator and electric unit
connector E111 (body side) terminal 10 (2WD) or 21 (4WD).
NOTE:
Connect positive lead of multimeter to combination meter connector M24 (body side) terminal 10 and negative lead to
ABS actuator and electric unit connector E111 (body side) terminal 10 (2WD) or 21 (4WD).
SBR675E
Continuity should exist.
Does continuity exist?
Ye s©Check combination meter.
Refer to EL-114, ªWARNING LAMPSº.
No©Repair harness or connectors.
8 REPLACE FUSE
Replace fuse.
Does the fuse blow out when ignition switch is turned ON?
Ye s©GO TO 9.
No©INSPECTION END
9 CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUIT FOR SHORT
1. Disconnect battery cable and ABS actuator and electric unit connector.
2. Check continuity between ABS actuator and electric unit connector E111 (body side) terminal 15 and ground.
SBR496E
Continuity should not exist.
Does continuity exist?
Ye s©Check the following.
If NG, repair harness or connector.
IHarness connector E111
IHarness for open or short between ABS actuator and electric unit and fuse
No©Replace ABS actuator and electric unit.
TROUBLE DIAGNOSES FOR SYMPTOMSABS
7. Warning Lamp Stays On When Ignition Switch Is Turned On (Cont'd)
BR-76

6 CHECK ABS OPERATING SIGNAL
1. Connect CONSULT-II to Data Link Connector.
2. Turn ignition switch ªONº. Set CONSULT-II in the active test mode to output an ABS operating signal.
(Refer to ªACTIVE TEST PROCEDUREº, ªCONSULT-II Inspection Procedureº, BR-47.)
3. An ABS operating signal lasts for 10 seconds. During the time the signal is being output, check resistance between
transfer control unit connector terminal 32 and ground.
Resistance: 0.5W, max.
SBR680E
Is resistance within specifications?
Ye s©CHECK transfer control unit.
Refer to TF-86, ªTROUBLE DIAGNOSIS FOR ABS OPERATION SIGNALº.
No©Replace ABS actuator and electric unit.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
8. Vehicle Vibrates Excessively When ABS Is Operating (Cont'd)
BR-79

Removal and InstallationNBBT0014IWhen removing or installing the seat trim, carefully handle it to keep dirt out and avoid damage.
HFor Wiring Diagram, refer to EL-181, ªPOWER SEATº for details.
CAUTION:
IBefore removing the front seat, turn the ignition switch off, disconnect both battery cables and wait
at least 3 minutes.
IWhen checking the power seat circuit for continuity using a circuit tester, do not confuse its con-
nector with the side air bag module connector. Such an error may cause the air bag to deploy.
IDo not drop, tilt, or bump the side air bag module installed in the seat. Always handle it with care.
SBT066A
SBT067A
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FRONT SEAT
Removal and Installation
BT-41

ENGINE CONTROL SYSTEM
SECTION
EC
CONTENTS
TROUBLE DIAGNOSIS - INDEX....................................8
Alphabetical & P No. Index for DTC ...........................8
PRECAUTIONS.............................................................14
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER².............14
Precautions for On Board Diagnostic (OBD)
System of Engine and A/T.........................................14
Engine Fuel & Emission Control System ..................15
Precautions ................................................................16
Wiring Diagrams and Trouble Diagnosis ...................17
PREPARATION.............................................................18
Special Service Tools ................................................18
Commercial Service Tools .........................................18
ENGINE AND EMISSION CONTROL OVERALL
SYSTEM.........................................................................20
Engine Control Component Parts Location ...............20
Circuit Diagram ..........................................................24
System Diagram ........................................................25
Vacuum Hose Drawing ..............................................26
System Chart .............................................................27
ENGINE AND EMISSION BASIC CONTROL
SYSTEM DESCRIPTION...............................................28
Multiport Fuel Injection (MFI) System .......................28
Electronic Ignition (EI) System ..................................30
Air Conditioning Cut Control ......................................31
Fuel Cut Control (at no load & high engine
speed) ........................................................................32
Evaporative Emission System ...................................32
Positive Crankcase Ventilation ..................................38
BASIC SERVICE PROCEDURE...................................39
Fuel Pressure Release ..............................................39
Fuel Pressure Check .................................................39
Fuel Pressure Regulator Check ................................40
Injector .......................................................................41
How to Check Idle Speed and Ignition Timing ..........42
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment .................................................................43
Idle Air Volume Learning ...........................................57ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................59
Introduction ................................................................59
Two Trip Detection Logic ...........................................59
Emission-related Diagnostic Information ...................60
Malfunction Indicator Lamp (MIL) ..............................74
OBD System Operation Chart ...................................75
CONSULT-II ...............................................................81
Generic Scan Tool (GST) ..........................................95
TROUBLE DIAGNOSIS - INTRODUCTION..................97
Introduction ................................................................97
Work Flow ..................................................................99
TROUBLE DIAGNOSIS - BASIC INSPECTION.........101
Basic Inspection.......................................................101
TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION............................................................. 116
DTC Inspection Priority Chart.................................. 116
Fail-safe Chart ......................................................... 117
Symptom Matrix Chart ............................................. 118
CONSULT-II Reference Value in Data Monitor
Mode ........................................................................122
Major Sensor Reference Graph in Data Monitor
Mode ........................................................................124
ECM Terminals and Reference Value .....................127
TROUBLE DIAGNOSIS - SPECIFICATION VALUE..136
Description ...............................................................136
Testing Condition .....................................................136
Inspection Procedure ...............................................136
Diagnostic Procedure ..............................................137
TROUBLE DIAGNOSIS FOR INTERMITTENT
INCIDENT.....................................................................140
Description ...............................................................140
Diagnostic Procedure ..............................................140
TROUBLE DIAGNOSIS FOR POWER SUPPLY........141
ECM Terminals and Reference Value .....................141
Main Power Supply and Ground Circuit ..................142
DTC P0100 MASS AIR FLOW SENSOR (MAFS)......150
Component Description ...........................................150
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