2005 INFINITI QX4 check engine

WARNING LAMPS
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Revision: October 20052005 QX56
Oil Pressure Warning Lamp Does Not Turn Off (Oil Pressure Is Normal)EKS00BCL
NOTE:
For oil pressure inspection, refer to LU-7, "
OIL PRESSURE CHECK" .
1. CHECK ENGINE OIL PRESSURE GAUGE OPERATION
Observe operation of engine oil pressure gauge.
Does engine oil pressure gauge function properly?
YES >> Replace the combination meter. Refer to IP-13, "Combination Meter" .
NO >> Go to DI-19, "
Engine Oil Pressure Signal Inspection" .

DI-64
REAR SONAR SYSTEM
Revision: October 20052005 QX56
Pre-diagnosis InspectionEKS00BD7
SENSOR STATUS CHECK

Check that the rear sonar sensor is properly aligned (bumper is not misaligned, no deformation in sensor
mounting area.

Check that snow, mud, or other foreign objects are not adhering to the rear sonar sensor.

Check that there is no deformation, scratches, or other damage to the rear sonar sensor.

Check that water has not accumulated in the rear sonar sensor.
CAUTION:
Use water, cotton swab, or other soft material for cleaning the sensor.
1. Check that there are no obstacles within each rear sonar sensor's detection range.
2. Check that there are no nearby ultrasound sources (such as the sounds of vehicle horns, motorcycle
engines, or truck air brakes).
3. Check that the vehicle is on a level surface.
Self-diagnosis FunctionEKS00BD8
There are four modes of self-diagnosis; entering diagnostics, requesting number of fault codes, requesting
fault codes, and idling or clearing fault codes. These steps must be followed in order. Self-diagnosis can be
manually exited by turning the ignition switch OFF, or selecting reverse gear. Self-diagnosis will exit unless a
fault code request occurs before a message is repeated five times without acknowledgement.
ENTERING DIAGNOSTICS MODE
1. Turn ignition switch ON. Rear sonar system OFF switch indica-
tor lamp illuminates for three seconds and then turns off.
2. Immediately push rear sonar system OFF switch ten times
within five seconds.
3. The sonar buzzer will sound once and the rear sonar system
OFF indicator will flash once.
REQUESTING NUMBER OF FAULT CODES MODE
1. While in diagnostic mode, push rear sonar system OFF switch
once.
2. The sonar buzzer will sound once.
3. Rear sonar system OFF indicator will flash once and sonar
buzzer will sound once for each fault code detected.
4. There will be a four second pause.
5. The number of fault codes will repeat five times then pause.
NOTE:
Self-diagnosis will exit unless requesting fault codes occurs
before five repeats ends.
Detection range
Rear sonar sensors Approx. 1.8 m (5.9 ft.) maximum
LKIA0389E
LKIA0388E

EC-1
ENGINE CONTROL SYSTEM
B ENGINE
CONTENTS
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SECTION EC
A
EC
Revision: October 20052005 QX56 INDEX FOR DTC ........................................................ 8
DTC No. Index ......................................................... 8
Alphabetical Index .................................................. 12
PRECAUTIONS ........................................................ 16
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ................................................................ 16
On Board Diagnostic (OBD) System of Engine and
A/T .......................................................................... 16
Precaution .............................................................. 16
Wiring Diagrams and Trouble Diagnosis ................ 19
PREPARATION ......................................................... 20
Special Service Tools ............................................. 20
Commercial Service Tools ...................................... 22
ENGINE CONTROL SYSTEM .................................. 23
System Diagram ..................................................... 23
Multiport Fuel Injection (MFI) System .................... 24
Electronic Ignition (EI) System ............................... 26
Fuel Cut Control (at No Load and High Engine
Speed) .................................................................... 27
AIR CONDITIONING CUT CONTROL ..................... 28
Input/Output Signal Chart ....................................... 28
System Description ................................................ 28
AUTOMATIC SPEED CONTROL DEVICE (ASCD) ... 29
System Description ................................................ 29
Component Description .......................................... 30
CAN COMMUNICATION .......................................... 31
System Description ................................................ 31
EVAPORATIVE EMISSION SYSTEM ....................... 32
Description ............................................................. 32
Component Inspection ........................................... 35
Removal and Installation ........................................ 36
How to Detect Fuel Vapor Leakage ....................... 37
ON BOARD REFUELING VAPOR RECOVERY
(ORVR) ...................................................................... 39
System Description ................................................ 39
Diagnostic Procedure ............................................. 40
Component Inspection ........................................... 43
POSITIVE CRANKCASE VENTILATION ................. 45Description .............................................................. 45
Component Inspection ............................................ 45
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-
NATS) ........................................................................ 47
Description .............................................................. 47
ON BOARD DIAGNOSTIC (OBD) SYSTEM ............ 48
Introduction ............................................................. 48
Two Trip Detection Logic ........................................ 48
Emission-related Diagnostic Information ................ 49
Malfunction Indicator Lamp (MIL) ........................... 64
OBD System Operation Chart ................................ 66
BASIC SERVICE PROCEDURE ............................... 72
Basic Inspection ..................................................... 72
Idle Speed and Ignition Timing Check .................... 77
Idle Mixture Ratio Adjustment ................................. 79
VIN Registration ..................................................... 90
Accelerator Pedal Released Position Learning ...... 90
Throttle Valve Closed Position Learning ................. 90
Idle Air Volume Learning ........................................ 91
Fuel Pressure Check .............................................. 93
TROUBLE DIAGNOSIS ............................................ 95
Trouble Diagnosis Introduction ............................... 95
DTC Inspection Priority Chart ...............................101
Fail-safe Chart ......................................................103
Symptom Matrix Chart ..........................................104
Engine Control Component Parts Location ..........108
Vacuum Hose Drawing .........................................114
Circuit Diagram .....................................................115
ECM Harness Connector Terminal Layout ...........117
ECM Terminals and Reference Value ...................117
CONSULT-II Function (ENGINE) ..........................126
Generic Scan Tool (GST) Function .......................139
CONSULT-II Reference Value in Data Monitor .....141
Major Sensor Reference Graph in Data Monitor
Mode .....................................................................144
TROUBLE DIAGNOSIS - SPECIFICATION VALUE .146
Description ............................................................146
Testing Condition ..................................................146
Inspection Procedure ............................................146
Diagnostic Procedure ...........................................147

EC-5
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ECA
Revision: October 20052005 QX56 Component Inspection ......................................... 413
Removal and Installation ...................................... 414
DTC P1146, P1166 HO2S2 ..................................... 415
Component Description ........................................ 415
CONSULT-II Reference Value in Data Monitor Mode
. 415
On Board Diagnosis Logic ................................... 415
DTC Confirmation Procedure ............................... 416
Overall Function Check ........................................ 416
Wiring Diagram .................................................... 418
Diagnostic Procedure ........................................... 421
Component Inspection ......................................... 424
Removal and Installation ...................................... 425
DTC P1147, P1167 HO2S2 ..................................... 426
Component Description ........................................ 426
CONSULT-II Reference Value in Data Monitor Mode
. 426
On Board Diagnosis Logic ................................... 426
DTC Confirmation Procedure ............................... 427
Overall Function Check ........................................ 427
Wiring Diagram .................................................... 429
Diagnostic Procedure ........................................... 432
Component Inspection ......................................... 435
Removal and Installation ...................................... 436
DTC P1148, P1168 CLOSED LOOP CONTROL .... 437
On Board Diagnosis Logic ................................... 437
DTC P1211 TCS CONTROL UNIT ......................... 438
Description ........................................................... 438
On Board Diagnosis Logic ................................... 438
DTC Confirmation Procedure ............................... 438
Diagnostic Procedure ........................................... 438
DTC P1212 TCS COMMUNICATION LINE ............ 439
Description ........................................................... 439
On Board Diagnosis Logic ................................... 439
DTC Confirmation Procedure ............................... 439
Diagnostic Procedure ........................................... 439
DTC P1217 ENGINE OVER TEMPERATURE ....... 440
Description ........................................................... 440
CONSULT-II Reference Value in Data Monitor Mode
. 440
On Board Diagnosis Logic ................................... 441
Overall Function Check ........................................ 441
Wiring Diagram .................................................... 443
Diagnostic Procedure ........................................... 445
Main 12 Causes of Overheating ........................... 448
Component Inspection ......................................... 449
DTC P1225 TP SENSOR ........................................ 450
Component Description ........................................ 450
On Board Diagnosis Logic ................................... 450
DTC Confirmation Procedure ............................... 450
Diagnostic Procedure ........................................... 451
Removal and Installation ...................................... 451
DTC P1226 TP SENSOR ........................................ 452
Component Description ........................................ 452
On Board Diagnosis Logic ................................... 452
DTC Confirmation Procedure ............................... 452
Diagnostic Procedure ........................................... 453
Removal and Installation ...................................... 453
DTC P1229 SENSOR POWER SUPPLY ................ 454On Board Diagnosis Logic ....................................454
DTC Confirmation Procedure ...............................454
Wiring Diagram .....................................................455
Diagnostic Procedure ...........................................456
DTC P1271, P1281 A/F SENSOR 1 .......................459
Component Description ........................................459
CONSULT-II Reference Value in Data Monitor Mode
.459
On Board Diagnosis Logic ....................................459
DTC Confirmation Procedure ...............................459
Wiring Diagram .....................................................461
Diagnostic Procedure ...........................................464
Removal and Installation ......................................467
DTC P1272, P1282 A/F SENSOR 1 .......................468
Component Description ........................................468
CONSULT-II Reference Value in Data Monitor Mode
.468
On Board Diagnosis Logic ....................................468
DTC Confirmation Procedure ...............................468
Wiring Diagram .....................................................470
Diagnostic Procedure ...........................................473
Removal and Installation ......................................476
DTC P1273, P1283 A/F SENSOR 1 .......................477
Component Description ........................................477
CONSULT-II Reference Value in Data Monitor Mode
.477
On Board Diagnosis Logic ....................................477
DTC Confirmation Procedure ...............................477
Wiring Diagram .....................................................479
Diagnostic Procedure ...........................................482
Removal and Installation ......................................486
DTC P1274, P1284 A/F SENSOR 1 .......................487
Component Description ........................................487
CONSULT-II Reference Value in Data Monitor Mode
.487
On Board Diagnosis Logic ....................................487
DTC Confirmation Procedure ...............................487
Wiring Diagram .....................................................489
Diagnostic Procedure ...........................................492
Removal and Installation ......................................496
DTC P1276, P1286 A/F SENSOR 1 .......................497
Component Description ........................................497
CONSULT-II Reference Value in Data Monitor Mode
.497
On Board Diagnosis Logic ....................................497
DTC Confirmation Procedure ...............................497
Overall Function Check ........................................498
Wiring Diagram .....................................................500
Diagnostic Procedure ...........................................503
Removal and Installation ......................................506
DTC P1278, P1288 A/F SENSOR 1 .......................507
Component Description ........................................507
CONSULT-II Reference Value in Data Monitor Mode
.507
On Board Diagnosis Logic ....................................507
DTC Confirmation Procedure ...............................508
Wiring Diagram .....................................................510
Diagnostic Procedure ...........................................513
Removal and Installation ......................................518

EC-20Revision: October 2005
PREPARATION
2005 QX56
PREPARATIONPFP:00002
Special Service ToolsUBS00KZ4
The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
EG17650301
(J-33984-A)
Radiator cap tester
adapterAdapting radiator cap tester to radiator cap and ra-
diator filler neck
a: 28 (1.10) dia.
b: 31.4 (1.236) dia.
c: 41.3 (1.626) dia.
Unit: mm (in)
KV10117100
(J-36471-A)
Heated oxygen sensor
wrenchLoosening or tightening heated oxygen sensors
with 22 mm (0.87 in) hexagon nut
KV10114400
(J-38365)
Heated oxygen sensor
wrenchLoosening or tightening heated oxygen sensors
a: 22 mm (0.87 in)
(J-44626)
Air fuel ratio (A/F) sen-
sor wrenchLoosening or tightening air fuel ratio (A/F) sensor 1
(J-44321)
Fuel pressure gauge
kitChecking fuel pressure
(J-44321-6)
Fuel pressure adapterConnecting fuel pressure gauge to quick connec-
tor type fuel lines.
(J-45488)
Quick connector re-
leaseRemove fuel tube quick connectors in engine
room.
S-NT564
S-NT379
S-NT636
LEM054
LEC642
LBIA0376E
PBIC0198E

PREPARATION
EC-21
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EC
Revision: October 20052005 QX56
KV109E0010
(J-46209)
Break-out boxMeasuring the ECM signals with a circuit tester
KV109E0080
(J-45819)
Y-cable adapterMeasuring the ECM signals with a circuit tester
(J-23688)
Engine coolant refrac-
tometerChecking concentration of ethylene glycol in en-
gine coolant Tool number
(Kent-Moore No.)
Tool nameDescription
S-NT825
S-NT826
W BIA0539E

EC-22Revision: October 2005
PREPARATION
2005 QX56
Commercial Service ToolsUBS00KZ5
Tool name
(Kent-Moore No.)Description
Leak detector
i.e.: (J-41416)Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD)Applying positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382)Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant tempera-
ture sensor
Oxygen sensor thread
cleaner
i.e.: (J-43897-18)
(J-43897-12)Reconditioning the exhaust system threads before
installing a new oxygen sensor. Use with anti-
seize lubricant shown below.
a: 18 mm diameter with pitch 1.5 mm for Zirco-
nia Oxygen Sensor
b: 12 mm diameter with pitch 1.25 mm for Tita-
nia Oxygen Sensor
Anti-seize lubricant
i.e.: (Permatex
TM
133AR or equivalent
meeting MIL specifica-
tion MIL-A-907)Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
S-NT703
S-NT704
S-NT815
S-NT705
AEM488
S-NT779

ON BOARD REFUELING VAPOR RECOVERY (ORVR)
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Revision: October 20052005 QX56
ON BOARD REFUELING VAPOR RECOVERY (ORVR)PFP:00032
System DescriptionUBS00KZJ
From the beginning of refueling, the air and vapor inside the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WA RN ING:
When conducting inspections below, be sure to observe the following:

Put a “CAUTION: INFLAMMABLE” sign in workshop.

Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.

Be sure to furnish the workshop with a CO2 fire extinguisher.
CAUTION:

Before removing fuel line parts, carry out the following procedures:
–Put drained fuel in an explosion-proof container and put lid on securely.
–Release fuel pressure from fuel line. Refer to EC-93, "FUEL PRESSURE RELEASE" .
–Disconnect battery ground cable.

Always replace O-ring when the fuel gauge retainer is removed.

Do not kink or twist hose and tube when they are installed.

Do not tighten hose and clamps excessively to avoid damaging hoses.

After installation, run engine and check for fuel leaks at connection.

Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, resulting in fuel spray and possibly a fire.
PBIB1068E