INFINITI QX56 2007 Factory Service Manual

LAN-30
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSES WORK FLOW
b. Reception item of “METER”: “VDC/TCS/ABS”, “3” is indicated in the “PAST”. This means M&A could not
receive the signal from ABS in the past. Draw a line between M&A and ABS (line 2-b in the figure).
c. Reception item of “TRANSMISSION”: “VDC/TCS/ABS”, “3” is indicated in the “PAST”. This means TCM
could not receive the signal from ABS in the past. Draw a line between TCM and ABS (line 2-c in the fig-
ure).
3. CAN DIAG SUPPORT MNTR (without PAST): Check the CAN DIAG SUPPORT MNTR (without PAST) of
units indicating “U1000” or “U1001” on SELF-DIAG RESULTS. Draw a line on the diagnosis sheet to indi-
cate the possible error circuit.
NOTE:
• While an error occurred in the past according to SELF-DIAG RESULTS, it is unclear which signal is not
received. Assume that errors were detected from all reception items.
• Draw a single line among the unit and all reception items. (Work flow differs from CAN DIAG SUPPORT
MNTR (with PAST).)
a. Reception item of “EPS”: Assume that the unit could not receive the signals from ECM, ABS, and M&A.
Draw a line among EPS, ECM, ABS, and M&A (line 3-a in the figure).
SKIB8732E

TROUBLE DIAGNOSES WORK FLOW
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b. Reception item of “ABS”: Assume that the unit could not receive the signal from ECM. Draw a line
between ABS and ECM (line 3-b in the figure).
4. Search for the possible cause using CAN communication signal chart using information from the interview
with the customer.
NOTE:
For the details of CAN communication signal, refer to LAN-44, "
CAN Communication Signal Chart".
a. ABS warning lamp turned ON and speedometer did not move: This means that “ABS warning lamp signal”
and “Vehicle speed signal” could not communicate between M&A and ABS (4-a in the figure).
SKIB8733E

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< SERVICE INFORMATION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSES WORK FLOW
b. The tachometer moved normally: This means that “Engine speed signal” could communicate normally
between ECM and M&A (4-b in the figure).
5. Fill out the diagnosis sheet based on information from step 4.
a. The ABS warning lamp turned ON and speedometer did not move: Assume that a possible cause is no
communication between M&A and ABS. Draw a line between M&A and ABS. (Line 5-a in the figure).
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TROUBLE DIAGNOSES WORK FLOW
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b. The tachometer moved normally: Put check marks between ECM and M&A. The circuit between ECM and
M&A is functioning properly (check marks 5-b in the figure).
6. The circuit which has the most amount of lines are the possible cause. Error is detected from ABS actua-
tor and electric unit (control unit) branch line (shaded in the figure).
NOTE:
For abbreviations, refer to LAN-37, "
Abbreviation List".
SKIB8735E

LAN-34
< SERVICE INFORMATION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSES WORK FLOW
7. Perform the inspection procedure for the possible cause. Refer to LAN-61, "Malfunction Area Chart".
Past Error — Short Circuit —
When the symptoms listed below exist, a short circuit of the CAN communication line is a possible cause.
SKIB8896E
Item (CONSULT-II) Indication Inspection procedure
SELF-DIAG RESULTS “U1000” and “U1001” is indicated in the past for most units.
Refer to LAN-61, "
Malfunction
Area Chart".
CAN DIAG SUPPORT MNTROnly on CAN DIAG SUPPORT MNTR (with PAST), “1 - 39” is in-
dicated on “PAST” of “TRANSMIT DIAG” and the reception item.

TROUBLE DIAGNOSES WORK FLOW
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SKIB8897E

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< SERVICE INFORMATION >[CAN]
INDEX FOR DTC
SERVICE INFORMATION
INDEX FOR DTC
DTC No. IndexINFOID:0000000003533619
DTCSelf-diagnosis item
(CONSULT-II indication)DTC detection condition Inspection
U1000 CAN COMM CIRCUITWhen ECM is not transmitting or receiving CAN
communication signal of OBD (emission-related
diagnosis) for 2 seconds or more.
Refer to LAN-37
. When a control unit (except for ECM) is not
transmitting or receiving CAN communication
signal for 2 seconds or more.
U1001 CAN COMM CIRCUITWhen ECM is not transmitting or receiving CAN
communication signal other than OBD (emis-
sion-related diagnosis) for 2 seconds or more.
U1002 SYSTEM COMMWhen a control unit is not transmitting or receiv-
ing CAN communication signal for 2 seconds or
less.Start the inspection. Re-
fer to the applicable sec-
tion of the indicated
control unit.
U1010 CONTROL UNIT [CAN]When an error is detected during the initial diag-
nosis for CAN controller of each control unit.Replace the control unit
indicating “U1010”.

HOW TO USE THIS SECTION
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HOW TO USE THIS SECTION
CautionINFOID:0000000003533620
• This section describes information peculiar to a vehicle, sheets for trouble diagnosis, and inspection proce-
dures.
• For trouble diagnosis procedure, refer to LAN-14, "
Trouble Diagnosis Procedure".
Abbreviation ListINFOID:0000000003533621
Abbreviations in CAN communication signal chart, and the diagnosis sheet are as per the following list.
Abbreviation Unit nameSELECT SYSTEM
(CONSULT-II)CAN DIAG SUPPORT MNTR
(CONSULT-II)
4WD Transfer control unit ALL MODE AWD/4WD AWD/4WD
A-BAG Air bag diagnosis sensor unit AIR BAG –
ABS ABS actuator and electric unit (control unit) ABS VDC/TCS/ABS
ADP Driver seat control unit AUTO DRIVE POS. –
BCM BCM BCM BCM/SEC
DISP Display control unit – DISPLAY
DLC Data link connector – –
ECM ECM ENGINE ECM
HVAC Front air control HVAC –
ICC ICC unit ICCICC
ICC/e4WD
IPDM-E IPDM E/R IPDM E/R IPDM E/R
LASER ICC sensor – ICC SENSOR
M&A Combination meter – METER/M&A
STRG Steering angle sensor – STRG
TCM A/T assembly A/T TCM

LAN-38
< SERVICE INFORMATION >[CAN]
PRECAUTIONS
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000003533622
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.
WARNING:
• 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 performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal
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 har-
ness connectors.
Precaution When Using CONSULT-IIINFOID:0000000003533623
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:0000000003533624
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:0000000003533625
• 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).
SKIB8766E

PRECAUTIONS
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• 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.
SKIB8767E