2005 INFINITI QX4 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

DI-80
REAR VIEW MONITOR
Revision: October 20052005 QX56
Side Distance Guideline CorrectionEKS00BDL
This mode is used to modify the side distance guidelines if they are dislocated from the rear view monitor
image, because of variations of body/camera mounting conditions.
SIDE DISTANCE GUIDELINE CORRECTION PROCEDURE
1. Create a correction line to modify the screen.
Draw lines on the rearward of the vehicle passing through the
following points: 200 mm (7.87 inch) from both sides of the vehi-
cle, and

*1: 0.5 m (1.5 feet)

*2: 1 m (3 feet)

*3: 2 m (7 feet)

*4: 3 m (10 feet)
and from the rear end of the bumper
2. With the ignition switch OFF, connect “CONSULT-II” and “CON-
SULT-II CONVERTER” to the data link connector, then turn igni-
tion switch ON. Touch “REARVIEW CAMERA” on “SELECT
SYSTEM” screen.
CAUTION:
Stop engine for safety when correcting side distance guide-
line.
3. Shift the A/T select lever to R position.
4. Touch “SELCT GUIDELINE PATTERN” on “SELECT WORK
ITEM” screen.
SKIA5637E
SKIA6103E
SKIA5638E

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-7
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Revision: October 20052005 QX56 DTC P2135 TP SENSOR ........................................ 604
Component Description ........................................ 604
CONSULT-II Reference Value in Data Monitor Mode
. 604
On Board Diagnosis Logic ................................... 604
DTC Confirmation Procedure ............................... 605
Wiring Diagram .................................................... 606
Diagnostic Procedure ........................................... 607
Component Inspection ......................................... 610
Removal and Installation ...................................... 610
DTC P2138 APP SENSOR ...................................... 611
Component Description ......................................... 611
CONSULT-II Reference Value in Data Monitor Mode
.. 611
On Board Diagnosis Logic .................................... 611
DTC Confirmation Procedure ............................... 612
Wiring Diagram .................................................... 613
Diagnostic Procedure ........................................... 614
Component Inspection ......................................... 618
Removal and Installation ...................................... 618
IGNITION SIGNAL .................................................. 619
Component Description ........................................ 619
Wiring Diagram .................................................... 620
Diagnostic Procedure ........................................... 625
Component Inspection ......................................... 629
Removal and Installation ...................................... 630
INJECTOR CIRCUIT ............................................... 631
Component Description ........................................ 631
CONSULT-II Reference Value in Data Monitor Mode
. 631
Wiring Diagram .................................................... 632
Diagnostic Procedure ........................................... 633
Component Inspection ......................................... 636
Removal and Installation ...................................... 636
FUEL PUMP CIRCUIT ............................................ 637
Description ........................................................... 637
CONSULT-II Reference Value in Data Monitor Mode
. 637
Wiring Diagram .................................................... 638
Diagnostic Procedure ........................................... 639
Component Inspection ......................................... 642
Removal and Installation ...................................... 642
REFRIGERANT PRESSURE SENSOR ................. 643
Component Description ........................................ 643Wiring Diagram .....................................................644
Diagnostic Procedure ...........................................645
Removal and Installation ......................................647
ELECTRICAL LOAD SIGNAL ................................648
Description ............................................................648
CONSULT-II Reference Value in Data Monitor Mode
.648
Diagnostic Procedure ...........................................648
ICC BRAKE SWITCH .............................................649
Component Description ........................................649
CONSULT-II Reference Value in Data Monitor Mode
.649
Wiring Diagram .....................................................650
Diagnostic Procedure ...........................................651
Component Inspection ..........................................656
ASCD BRAKE SWITCH .........................................657
Component Description ........................................657
CONSULT-II Reference Value in Data Monitor Mode
.657
Wiring Diagram .....................................................658
Diagnostic Procedure ...........................................659
Component Inspection ..........................................663
ASCD INDICATOR ..................................................664
Component Description ........................................664
CONSULT-II Reference Value in Data Monitor Mode
.664
Wiring Diagram .....................................................665
Diagnostic Procedure ...........................................666
MIL AND DATA LINK CONNECTOR ......................667
Wiring Diagram .....................................................667
SERVICE DATA AND SPECIFICATIONS (SDS) ....669
Fuel Pressure .......................................................669
Idle Speed and Ignition Timing .............................669
Calculated Load Value ..........................................669
Mass Air Flow Sensor ...........................................669
Intake Air Temperature Sensor .............................669
Engine Coolant Temperature Sensor ...................669
A/F Sensor 1 Heater .............................................669
Heated Oxygen sensor 2 Heater ..........................669
Crankshaft Position Sensor (POS) .......................669
Camshaft Position Sensor (PHASE) ....................669
Throttle Control Motor ...........................................669
Injector ..................................................................670
Fuel Pump ............................................................670

EC-16Revision: October 2005
PRECAUTIONS
2005 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
UBS00KZ0
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WAR NIN G:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
On Board Diagnostic (OBD) System of Engine and A/TUBS00KZ1
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:

Be sure to turn the ignition switch OFF and disconnect the negative battery cable before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves,
etc. will cause the MIL to light up.

Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)

Certain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to PG-67, "
HAR-
NESS CONNECTOR" .

Be sure to route and secure the harnesses properly after work. The interference of the harness
with a bracket, etc. may cause the MIL to light up due to the short circuit.

Be sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the EVAP system or fuel injection system,
etc.

Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
PrecautionUBS00KZ2

Always use a 12 volt battery as power source.

Do not attempt to disconnect battery cables while engine is
running.

Before connecting or disconnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect negative
battery cable. Failure to do so may damage the ECM
because battery voltage is applied to ECM even if ignition
switch is turned OFF.

Before removing parts, turn ignition switch OFF and then
disconnect battery ground cable.
SEF 2 89 H

PRECAUTIONS
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EC
Revision: October 20052005 QX56

Do not disassemble ECM.

If a battery cable is disconnected, the memory will return to
the ECM value.
The ECM will now start to self-control at its initial value.
Engine operation can vary slightly when the terminal is dis-
connected. However, this is not an indication of a malfunc-
tion. Do not replace parts because of a slight variation.

If the battery is disconnected, the following emission-
related diagnostic information will be lost within 24 hours.
–Diagnostic trouble codes
–1st trip diagnostic trouble codes
–Freeze frame data
–1st trip freeze frame data
–System readiness test (SRT) codes
–Test values

When connecting ECM harness connector, fasten it
securely with a lever as far as it will go as shown in the fig-
ure.

When connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.

Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge)
voltage to develop in coil and condenser, thus resulting in
damage to ICs.

Keep engine control system harness at least 10 cm (4 in)
away from adjacent harness, to prevent engine control sys-
tem malfunctions due to receiving external noise, degraded
operation of ICs, etc.

Keep engine control system parts and harness dry.

Before replacing ECM, perform ECM Terminals and Refer-
ence Value inspection and make sure ECM functions prop-
erly. Refer to EC-117, "
ECM Terminals and Reference Value"
.

Handle mass air flow sensor carefully to avoid damage.

Do not disassemble mass air flow sensor.

Do not clean mass air flow sensor with any type of deter-
gent.

Do not disassemble electric throttle control actuator.

Even a slight leak in the air intake system can cause seri-
ous incidents.

Do not shock or jar the camshaft position sensor (PHASE), crankshaft position sensor (POS).
PBIB11 64 E
BBIA0387E
PBIB0090E
MEF040D