2007 INFINITI QX56 service

LAN-1
ELECTRICAL
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SECTION LAN
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CONTENTS
LAN SYSTEM
CAN FUNDAMENTAL
SERVICE INFORMATION ............................
3
PRECAUTIONS ...................................................3
Precaution When Using CONSULT-II .......................3
Precaution for Trouble Diagnosis ..............................3
Precaution for Harness Repair ..................................3
SYSTEM DESCRIPTION .....................................4
CAN Communication System ....................................4
Diag on CAN .............................................................5
TROUBLE DIAGNOSIS ......................................7
Condition of Error Detection ......................................7
Symptom When Error Occurs in CAN Communi-
cation System ............................................................
7
Self-Diagnosis .........................................................10
CAN Diagnostic Support Monitor ............................10
TROUBLE DIAGNOSES WORK FLOW ............13
Information Needed for Trouble Diagnosis .............13
How to Use CAN Communication Signal Chart ......13
Trouble Diagnosis Flow Chart .................................14
Trouble Diagnosis Procedure ..................................14
CAN
SERVICE INFORMATION ...........................
36
INDEX FOR DTC ................................................36
DTC No. Index ........................................................36
HOW TO USE THIS SECTION ...........................37
Caution ....................................................................37
Abbreviation List ......................................................37
PRECAUTIONS ..................................................38
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .................................................................
38
Precaution When Using CONSULT-II .....................38
Precaution for Trouble Diagnosis ............................38
Precaution for Harness Repair ................................38
TROUBLE DIAGNOSIS ....................................40
CAN Diagnostic Support Monitor .............................40
CAN System Specification Chart .............................44
CAN Communication Signal Chart ..........................44
Schematic ................................................................49
Wiring Diagram - CAN - ...........................................50
Interview Sheet ........................................................53
Data Sheet ...............................................................54
CAN System (Type 1) ..............................................57
CAN System (Type 2) ..............................................58
CAN System (Type 3) ..............................................59
CAN System (Type 4) ..............................................60
Component Parts Location ......................................61
Harness Layout .......................................................61
Malfunction Area Chart ............................................61
Main Line Between TCM and Driver Seat Control
Unit ..........................................................................
62
Main Line Between TCM and ICC Sensor ...............63
Main Line Between ICC Sensor and ICC Unit .........64
Main Line Between ICC Unit and Driver Seat Con-
trol Unit ....................................................................
65
Main Line Between Driver Seat Control Unit and
Data Link Connector ................................................
65
Main Line Between Data Link Connector and ABS
Actuator and Electric Unit (Control Unit) ..................
66
ECM Branch Line Circuit .........................................67
TCM Branch Line Circuit .........................................67
ICC Sensor Branch Line Circuit ...............................68
ICC Unit Branch Line Circuit ....................................69
Driver Seat Control Unit Branch Line Circuit ...........69
BCM Branch Line Circuit .........................................70
Display Control Unit Branch Line Circuit .................70
Data Link Connector Branch Line Circuit ................71
Front Air Control Branch Line Circuit .......................71
Combination Meter Branch Line Circuit ...................72
Steering Angle Sensor Branch Line Circuit .............72
Transfer Control Unit Branch Line Circuit ................73
ABS Actuator and Electric Unit (Control Unit)
Branch Line Circuit ..................................................
74

PRECAUTIONS
LAN-3
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
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SERVICE INFORMATION
PRECAUTIONS
Precaution When Using CONSULT-IIINFOID:0000000003533606
Use CONSULT-II CONVERTER when connecting CONSULT-II to data link connector.
CAUTION:
CAN communication does not function properly if CONSULT-II is used without connecting CONSULT-II
CONVERTER.
Precaution for Trouble DiagnosisINFOID:0000000003533607
CAUTION:
• Never apply 7.0 V or more to the measurement terminal.
• Use a tester with open terminal voltage of 7.0 V or less.
• Turn the ignition switch OFF and disconnect the battery cable from the negative terminal when
checking the harness.
Precaution for Harness RepairINFOID:0000000003533608
• Solder the repaired area and wrap tape around the soldered area.
NOTE:
A fray of twisted lines must be within 110 mm (4.33 in).
• Bypass connection is never allowed at the repaired area.
NOTE:
Bypass connection may cause CAN communication error. The
spliced wire becomes separated and the characteristics of twisted
line are lost.
• Replace the applicable harness as an assembly if error is detected on the shield lines of CAN communica-
tion line.
SKIB8766E
SKIB8767E

LAN-4
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
SYSTEM DESCRIPTION
SYSTEM DESCRIPTION
CAN Communication SystemINFOID:0000000003533609
• CAN communication is a multiplex communication system. This enables the system to transmit and receive
large quantities of data at high speed by connecting control units with two communication lines (CAN-H and
CAN-L).
• Control units on the CAN network transmit signals using the CAN communication control circuit. They
receive only necessary signals from other control units to operate various functions.
• CAN communication lines adopt twisted-pair line style (two lines twisted) for noise immunity.
SYSTEM DIAGRAM
Each control unit passes an electric current to the termination circuits when transmitting CAN communication
signal. The termination circuits produce an electrical potential difference between CAN-H and CAN-L. CAN
communication system transmits and receives CAN communication signals by the potential difference.
SKIB8887E
Component Description
Main line CAN communication line between splices
Branch line CAN communication line between splice and a control unit
Splice A point connecting a branch line with a main line
Termination circuit Refer to "CAN COMMUNICATION CONTROL CIRCUIT".

SYSTEM DESCRIPTION
LAN-5
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
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CAN COMMUNICATION CONTROL CIRCUIT
*: These are the only control units wired with both ends of CAN communication system.
Diag on CANINFOID:0000000003533610
DESCRIPTION
“Diag on CAN” is a diagnosis using CAN communication instead of previous DDL1 and DDL2 communication
line, between control unit and diagnosis unit.
SKIB8713E
Component System description
CAN controller It controls CAN communication signal transmission and reception, error detection, etc.
Transceiver ICIt converts digital signal into CAN communication signal, and CAN communication signal into digital
signal.
Noise filter It eliminates noise of CAN communication signal.
Termination circuit
*
(Resistance of approx. 120 Ω)It produces potential difference.

LAN-6
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
SYSTEM DESCRIPTION
System Diagram
SKIB8714E
Name Harness Description
DDL1Tx
RxIt is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling)
DDL2 K-LINE It is used for trouble diagnosis. (CAN-H and CAN-L are used for controlling)
Diag on CANCAN-H
CAN-LIt is used for trouble diagnosis and control.

TROUBLE DIAGNOSIS
LAN-7
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
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TROUBLE DIAGNOSIS
Condition of Error DetectionINFOID:0000000003533611
“U1000” or “U1001” is indicated on SELF-DIAG RESULTS on CONSULT-II if CAN communication signal is not
transmitted or received between units for 2 seconds or more.
CAN COMMUNICATION SYSTEM ERROR
• CAN communication line open (CAN-H, CAN-L, or both)
• CAN communication line short (ground, between CAN communication lines, other harnesses)
• Error of CAN communication control circuit of the unit connected to CAN communication line
WHEN INDICATED “U1000” OR “U1001” IS INDICATED EVEN THOUGH CAN COMMUNICATION
SYSTEM IS NORMAL
• CONSULT-II CONVERTER not connected: Error may be detected by the self-diagnosis when not using
CONSULT-II CONVERTER (Depending on the control unit which carries out CAN communication).
• Removal/installation of parts: Error may be detected when removing and installing CAN communication unit
and related parts while turning the ignition switch ON. (A DTC except for CAN communication may be
detected.)
• Fuse blown out (removed): CAN communication of the unit may cease.
• Voltage drop: Error may be detected if voltage drops due to discharged battery when turning the ignition
switch ON (Depending on the control unit which carries out CAN communication).
• Error may be detected if the power supply circuit of the control unit, which carries out CAN communication,
malfunctions (Depending on the control unit which carries out CAN communication).
• Error may be detected if reprogramming is not completed normally.
NOTE:
CAN communication system is normal if “U1000” or “U1001” is indicated on SELF-DIAG RESULTS of CON-
SULT-II under the above conditions. Erase the memory of the self-diagnosis of each unit.
Symptom When Error Occurs in CAN Communication SystemINFOID:0000000003533612
In CAN communication system, multiple units mutually transmit and receive signals. Each unit cannot transmit
and receive signals if any error occurs on CAN communication line. Under this condition, multiple control units
related to the root cause malfunction or go into fail-safe mode.
ERROR EXAMPLE
NOTE:
• Each vehicle differs in symptom of each unit under fail-safe mode and CAN communication line wiring.
• Refer to LAN-37, "
Abbreviation List" for the unit abbreviation.
Example: TCM branch line open circuit
SKIB8738E

LAN-8
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSIS
Example: Data link connector branch line open circuit
NOTE:
• When data link connector branch line is open, transmission and reception of CAN communication signals is
not affected. Therefore, no symptoms occur. However, be sure to repair malfunctioning circuit.
• When data link connector branch line is open, the screen-display of the CONSULT-II “SELECT SYSTEM”
screen may be the same as when the CAN communication line has short-circuit. However, symptoms differ
depending on the case. See below chart for the differences.
Unit name Symptom
ECM Engine torque limiting is affected, and shift harshness increases.
BCM Reverse warning chime does not sound.
EPS control unit Normal operation.
Combination meter• Shift position indicator and OD OFF indicator turn OFF.
• Warning lamps turn ON.
ABS actuator and electric unit (control unit) Normal operation.
TCM No impact on operation.
IPDM E/R Normal operation.
SKIB8739E
Unit name Symptom
ECM
Normal operation. BCM
EPS control unit
Combination meter
ABS actuator and electric unit (control unit)
TCM
IPDM E/R
SELECT SYSTEM
(CONSULT-II)Difference of symptom
Data link connector branch line open circuit
All Diag on CAN units are not
indicated.Normal operation.
CAN-H, CAN-L harness short-circuitMost the units which are connected to the CAN com-
munication system enter fail-safe mode or are deac-
tivated.

TROUBLE DIAGNOSIS
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< SERVICE INFORMATION >[CAN FUNDAMENTAL]
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Example: CAN-H, CAN-L Harness Short Circuit
SKIB8740E
Unit name Symptom
ECM Engine torque limiting is affected, and shift harshness increases.
BCM• Reverse warning chime does not sound.
• The front wiper moves under continuous operation mode even though the front wip-
er switch being in the intermittent position.
EPS control unit The steering effort increases.
Combination meter• The shift position indicator and OD OFF indicator turn OFF.
• The speedometer is inoperative.
• The odo/trip meter stops.
ABS actuator and electric unit (control unit) Normal operation.
TCM No impact on operation.
IPDM E/RWhen the ignition switch is ON,
• The headlamps (Lo) turn ON.
• The cooling fan continues to rotate.
SKIB8741E