2004 INFINITI QX56 Can communication

DI-6
COMBINATION METERS
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POWER SUPPLY AND GROUND CIRCUIT
Power is supplied at all times

through 10A fuse [No.19, located in the fuse block (J/B)]

to combination meter terminal 8.
With the ignition switch in the ON or START position, power is supplied

through 10A fuse [No.14, located in the fuse block (J/B)]

to combination meter terminal 24.
With the ignition switch in the ACC or ON position, power is supplied

through 10A fuse [No.4, located in the fuse block (J/B)]

to combination meter terminal 1.
Ground is supplied

to combination meter terminal 17

through body grounds M57, M61 and M79.
WATER TEMPERATURE GAUGE
The water temperature gauge indicates the engine coolant temperature.
ECM provides an engine coolant temperature signal to combination meter via CAN communication lines.
ENGINE OIL PRESSURE GAUGE
The engine oil pressure gauge indicates the engine oil pressure.
The engine oil pressure gauge is regulated by the unified meter control unit and input from the oil pressure
sensor.
A/T OIL TEMPERATURE GAUGE
The A/T oil temperature gauge indicates the A/T fluid temperature.
TCM (transmission control module) provides an A/T fluid temperature signal to combination meter via CAN
communication lines.
V O LTA G E G A U G E
The voltage gauge indicates the battery/charging system voltage.
The voltage gauge is regulated by the unified meter control unit.
TACHOMETER
The tachometer indicates engine speed in revolutions per minute (rpm).
ECM provides an engine speed signal to combination meter via CAN communication lines.
FUEL GAUGE
The fuel gauge indicates the approximate fuel level in the fuel tank.
The fuel gauge is regulated by the unified meter control unit and a variable resistor signal supplied

to combination meter terminal 15.

through fuel level sensor unit and fuel pump terminal 2

through fuel level sensor unit and fuel pump terminal 5

from combination meter terminal 16
SPEEDOMETER
ABS actuator and electric unit (control unit) provides a vehicle speed signal to the combination meter via CAN
communication lines.
CAN COMMUNICATION SYSTEM DESCRIPTION
Refer to LAN-5, "CAN COMMUNICATION" .

DI-44
WARNING CHIME
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System DescriptionEKS007EF
FUNCTION
Power is supplied at all times

through 50A fusible link (letter f , located in the fuse and fusible link box)

to BCM terminal 70, and

through 10A fuse [No. 19, located in the fuse block (J/B)]

to key switch and key lock solenoid terminal 3.
With ignition switch in ON or START position, power is supplied

through 10A fuse [No. 59, located in the fuse and relay box)

to BCM terminal 38.
Ground is supplied

to BCM terminal 67

through body grounds M57, M61, and M79.
NOTE:
When ignition key warning chime, light warning chime, and seat belt warning chime are required at the same
time, the priorities for each chime are the following.
1. Light warning chime
2. Ignition key warning chime
3. Seat belt warning chime
IGNITION KEY WARNING CHIME
With the key inserted in the ignition switch, the ignition switch in OFF position, and the driver's door open, the
warning chime will sound.
Power is supplied

through key switch and key lock solenoid terminal 4

to BCM terminal 37.
Ground is supplied

to BCM terminal 47

through front door switch LH terminal 2.
Front door switch LH is case grounded.
BCM detects key inserted into the ignition switch, and sends key warning signal to combination meter via CAN
communication lines. When the combination meter receives key warning signal, it sounds warning chime.
LIGHT WARNING CHIME
With the key removed from the ignition switch, the driver's door open, and the lighting switch (part of the com-
bination switch) in 1st or 2nd position, the warning chime will sound. [Except when headlamp battery saver
control operates (5 minutes after ignition switch is turned to OFF or ACC position) and headlamps do not illu-
minate.]
Signal is supplied

from combination switch (lighting switch) terminals 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10

to BCM terminals 2, 3, 4, 5, 6, 32, 33, 34, 35 and 36.
NOTE:
BCM detected lighting switch in 1st or 2nd position. Refer to BCS-3, "
COMBINATION SWITCH READING
FUNCTION" .
Ground is supplied

to BCM terminal 47

through front door switch LH terminal 2.
Front door switch LH is case grounded.
BCM detects headlamps are illuminated, and sends light warning signal to combination meter CAN communi-
cation lines. When the combination meter receives light warning signal, it sounds warning chime.
SEAT BELT WARNING CHIME
When the ignition switch is turned ON with the seat belt unfastened (seat belt buckle switch LH unfastened),
warning chime will sound for approximately 6 seconds.

WARNING CHIME
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Ground is supplied

to combination meter terminal 27

through seat belt buckle pre-tensioner assembly LH (seat belt buckle switch) terminal 1.
Seat belt buckle pre-tensioner assembly LH (seat belt buckle switch) terminal 2 is grounded through body
grounds B7 and B19.
The combination meter sends seat belt buckle switch LH unfastened signal to BCM via CAN communication
line.
BCM receives seat belt buckle switch LH unfastened signal from combination meter via CAN communication
line, and sends seat belt warning signal to the combination meter via CAN communication line. When the
combination meter receives the seat belt warning signal, it sounds the warning chime. The BCM controls the
(6 second) duration of the seat belt warning chime.
CAN Communication System DescriptionEKS007EG
Refer to LAN-5, "CAN COMMUNICATION" .

WARNING CHIME
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CONSULT-II Function (BCM)EKS007EM
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II BASIC OPERATION PROCEDURE
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
1. With the ignition switch OFF, connect “CONSULT-II” and “CON-
SULT-II CONVERTER” to the data link connector, and turn igni-
tion switch ON.
2. Touch “START (NISSAN BASED VHCL)”.
3. Touch “BCM” on “SELECT SYSTEM” screen. If “BCM” is not
indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC)
Circuit" .
BCM
diagnostic test itemDiagnostic mode Description
Inspection by partWORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the BCM
for setting the status suitable for required operation, input/output signals are
received from the BCM and received data is displayed.
DATA MONITOR Displays BCM input/output data in real time.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
SELF-DIAG RESULTS Displays BCM self-diagnosis results.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ECU PART NUMBER BCM part number can be read.
CONFIGURATION Performs BCM configuration read/write functions.
BBIA0369E
BCIA0029E
BCIA0030E

WARNING CHIME
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Display Item List
All Warning Chimes Do Not OperateEKS007EN
1. CHECK BCM CHIME OPERATION
Select “BUZZER” on CONSULT-II, and perform “LIGHT WARN
ALM”, "IGN KEY WARN ALM", OR "SEAT BELT WARN" active test.
Does chime sound?
YES >> Replace the BCM. Refer to BCS-19, "Removal and
Installation of BCM" .
NO >> Replace the combination meter. Refer to DI-25,
"Removal and Installation of Combination Meter" .
Key Warning Chime and Light Warning Chime Do Not Operate (Seat Belt Warn-
ing Chime Does Operate)
EKS007EO
1. CHECK BCM INPUT SIGNAL
With CONSULT-II
1. Select "BCM" on CONSULT-II.
2. With "DATA MONITOR" of "BUZZER", confirm "DOOR SW-DR"
changes with the status of front door LH.
Without CONSULT-II
Check voltage between BCM harness connector M19 terminal 47
(SB) and ground.
OK or NG
OK >> Replace the BCM. Refer to BCS-19, "Removal and
Installation of BCM" .
NG >> GO TO 2.
Monitored Item CONSULT-II display Description
CAN communication CAN communication [U1000] Malfunction is detected in CAN communication.
CAN communication system CAN communication system 1 to 6 [U1000] Malfunction is detected in CAN system.
SKIA6331E
When front door LH is
opened: DOOR SW-DR ON
When front door LH is
closed: DOOR SW-DR OFF
LKIA0335E
When front door LH is
opened: Approx. 0V
When front door LH is
closed: Approx. 5V
WKIA1515E

REAR VIEW MONITOR
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CONSULT-II Function (REARVIEW CAMERA)EKS007R9
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II BASIC OPERATION
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
1. With the ignition switch OFF, connect “CONSULT-II” and “CON-
SULT-II CONVERTER” to the data link connector, then turn igni-
tion switch ON.
2. Touch “START (NISSAN BASED VHCL)”.
3. Touch “REARVIEW CAMERA” on “SELECT SYSTEM” screen. If
“REARVIEW CAMERA” is not indicated, go to GI-39, "
CON-
SULT-II Data Link Connector (DLC) Circuit" .
REARVIEW CAMERA
diagnostic modeDescription
WORK SUPPORTSupports inspection and adjustments. Commands are transmitted to the rearview camera control unit
for setting the status suitable for required operation, input/output signals are received from the rear-
view camera control unit and received data is displayed.
DATA MONITOR Displays rearview camera control unit input/output data in real time.
ECU PART NUMBER Rearview camera control unit part number can be read.
BBIA0369E
BCIA0029E
BCIA0030E

EC-1
ENGINE CONTROL SYSTEM
B ENGINE
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SECTION EC
A
EC
Revision: August 20072004 QX56 INDEX FOR DTC ........................................................ 8
Alphabetical Index .................................................... 8
DTC No. 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
Vacuum Hose Drawing ........................................... 24
System Chart ......................................................... 25
Multiport Fuel Injection (MFI) System .................... 26
Electronic Ignition (EI) System ............................... 28
Nissan Torque Demand (NTD) Control System ..... 29
Air Conditioning Cut Control ................................... 30
Fuel Cut Control (at No Load and High Engine
Speed) .................................................................... 30
CAN communication .............................................. 31
BASIC SERVICE PROCEDURE .............................. 32
Idle Speed and Ignition Timing Check .................... 32
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment ............................................................. 33
Accelerator Pedal Released Position Learning ...... 44
Throttle Valve Closed Position Learning ................ 44
Idle Air Volume Learning ........................................ 44
Fuel Pressure Check .............................................. 46
ON BOARD DIAGNOSTIC (OBD) SYSTEM ............ 49
Introduction ............................................................ 49
Two Trip Detection Logic ........................................ 49
Emission-related Diagnostic Information ................ 50
IVIS (Infiniti Vehicle Immobilizer System — NATS) ... 63
Malfunction Indicator Lamp (MIL) ........................... 63
OBD System Operation Chart ................................ 66TROUBLE DIAGNOSIS ............................................ 71
Trouble Diagnosis Introduction ............................... 71
DTC Inspection Priority Chart ................................. 76
Fail-safe Chart ........................................................ 77
Basic Inspection ..................................................... 79
Symptom Matrix Chart ............................................ 84
Engine Control Component Parts Location ............ 88
Circuit Diagram ....................................................... 94
ECM Harness Connector Terminal Layout ............. 96
ECM Terminals and Reference Value ..................... 96
CONSULT-II Function ...........................................103
Generic Scan Tool (GST) Function .......................116
CONSULT-II Reference Value in Data Monitor .....118
Major Sensor Reference Graph in Data Monitor
Mode .....................................................................121
TROUBLE DIAGNOSIS - SPECIFICATION VALUE .123
Description ............................................................123
Testing Condition ..................................................123
Inspection Procedure ............................................123
Diagnostic Procedure ...........................................124
TROUBLE DIAGNOSIS FOR INTERMITTENT INCI-
DENT .......................................................................127
Description ............................................................127
Diagnostic Procedure ...........................................127
POWER SUPPLY AND GROUND CIRCUIT ...........128
Wiring Diagram .....................................................128
Diagnostic Procedure ...........................................129
Ground Inspection ................................................133
DTC U1000, U1001 CAN COMMUNICATION LINE .135
Description ............................................................135
On Board Diagnosis Logic ....................................135
DTC Confirmation Procedure ...............................135
Wiring Diagram .....................................................136
Diagnostic Procedure ...........................................137
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER .138
Description ............................................................138
CONSULT-II Reference Value in Data Monitor Mode
.138
On Board Diagnosis Logic ....................................138
DTC Confirmation Procedure ...............................139

EC-5
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Revision: August 20072004 QX56 Overall Function Check ........................................ 396
Wiring Diagram .................................................... 398
Diagnostic Procedure ........................................... 401
Component Inspection ......................................... 404
Removal and Installation ...................................... 406
DTC P1148, P1168 CLOSED LOOP CONTROL .... 407
On Board Diagnosis Logic ................................... 407
DTC P1211 TCS CONTROL UNIT ......................... 408
Description ........................................................... 408
On Board Diagnosis Logic ................................... 408
DTC Confirmation Procedure ............................... 408
Diagnostic Procedure ........................................... 408
DTC P1212 TCS COMMUNICATION LINE ............ 409
Description ........................................................... 409
On Board Diagnosis Logic ................................... 409
DTC Confirmation Procedure ............................... 409
Diagnostic Procedure ........................................... 409
DTC P1217 ENGINE OVER TEMPERATURE ....... 410
Description ........................................................... 410
CONSULT-II Reference Value in Data Monitor Mode
. 410
On Board Diagnosis Logic .................................... 411
Overall Function Check ......................................... 411
Wiring Diagram .................................................... 413
Diagnostic Procedure ........................................... 415
Main 12 Causes of Overheating ........................... 418
Component Inspection ......................................... 419
DTC P1225 TP SENSOR ........................................ 420
Component Description ........................................ 420
On Board Diagnosis Logic ................................... 420
DTC Confirmation Procedure ............................... 420
Diagnostic Procedure ........................................... 421
Removal and Installation ...................................... 421
DTC P1226 TP SENSOR ........................................ 422
Component Description ........................................ 422
On Board Diagnosis Logic ................................... 422
DTC Confirmation Procedure ............................... 422
Diagnostic Procedure ........................................... 423
Removal and Installation ...................................... 423
DTC P1229 SENSOR POWER SUPPLY ................ 424
On Board Diagnosis Logic ................................... 424
DTC Confirmation Procedure ............................... 424
Wiring Diagram .................................................... 425
Diagnostic Procedure ........................................... 426
DTC P1271, P1281 A/F SENSOR 1 ....................... 429
Component Description ........................................ 429
CONSULT-II Reference Value in Data Monitor Mode
. 429
On Board Diagnosis Logic ................................... 429
DTC Confirmation Procedure ............................... 429
Wiring Diagram .................................................... 431
Diagnostic Procedure ........................................... 434
Removal and Installation ...................................... 436
DTC P1272, P1282 A/F SENSOR 1 ....................... 437
Component Description ........................................ 437
CONSULT-II Reference Value in Data Monitor Mode
. 437
On Board Diagnosis Logic ................................... 437
DTC Confirmation Procedure ............................... 437Wiring Diagram .....................................................439
Diagnostic Procedure ...........................................442
Removal and Installation ......................................444
DTC P1273, P1283 A/F SENSOR 1 .......................445
Component Description ........................................445
CONSULT-II Reference Value in Data Monitor Mode
.445
On Board Diagnosis Logic ....................................445
DTC Confirmation Procedure ...............................445
Wiring Diagram .....................................................447
Diagnostic Procedure ...........................................450
Removal and Installation ......................................453
DTC P1274, P1284 A/F SENSOR 1 .......................454
Component Description ........................................454
CONSULT-II Reference Value in Data Monitor Mode
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On Board Diagnosis Logic ....................................454
DTC Confirmation Procedure ...............................454
Wiring Diagram .....................................................456
Diagnostic Procedure ...........................................459
Removal and Installation ......................................462
DTC P1276, P1286 A/F SENSOR 1 .......................463
Component Description ........................................463
CONSULT-II Reference Value in Data Monitor Mode
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On Board Diagnosis Logic ....................................463
DTC Confirmation Procedure ...............................463
Overall Function Check ........................................464
Wiring Diagram .....................................................466
Diagnostic Procedure ...........................................469
Removal and Installation ......................................471
DTC P1278, P1288 A/F SENSOR 1 .......................472
Component Description ........................................472
CONSULT-II Reference Value in Data Monitor Mode
.472
On Board Diagnosis Logic ....................................472
DTC Confirmation Procedure ...............................473
Wiring Diagram .....................................................475
Diagnostic Procedure ...........................................478
Removal and Installation ......................................483
DTC P1279, P1289 A/F SENSOR 1 .......................484
Component Description ........................................484
CONSULT-II Reference Value in Data Monitor Mode
.484
On Board Diagnosis Logic ....................................484
DTC Confirmation Procedure ...............................485
Wiring Diagram .....................................................487
Diagnostic Procedure ...........................................490
Removal and Installation ......................................495
DTC P1444 EVAP CANISTER PURGE VOLUME
CONTROL SOLENOID VALVE ...............................496
Description ............................................................496
CONSULT-II Reference Value in Data Monitor Mode
.496
On Board Diagnosis Logic ....................................497
DTC Confirmation Procedure ...............................497
Wiring Diagram .....................................................498
Diagnostic Procedure ...........................................500