2008 INFINITI QX56 ECU

LAN-8
< FUNCTION DIAGNOSIS >[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
are not affected. Therefore, no symptoms occur. However, be sure to repair malfunctioning circuit.
• When data link connector branch line is open, “ECU list” displayed on the CONSULT-III “CAN DIAG SUP- PORT MNTR” may be the same as when the CAN communication line has short-circuit. However, symp-
toms differ depending on the case. See below chart for the differences.
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.
Unit name
Symptom
SKIB8739E
Unit nameSymptom
ECM
Normal operation.
BCM
EPS control unit
Combination meter
ABS actuator and electric unit (control unit)
TCM
IPDM E/R
“ECU list” on the “CAN DIAG SUPPORT MNTR”(CONSULT-III) 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-circuit Most of the units which are connected to the CAN
communication system enter fail-safe mode or are
deactivated.
Revision: March 2010
2008 QX56

LAN
DIAGNOSIS AND REPAIR WORKFLOWLAN-13
< BASIC INSPECTION > [CAN FUNDAMENTAL]
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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Information Needed for Trouble DiagnosisINFOID:0000000001374970
CAN communication system performs trouble diagnosis with the following tools.
How to Use CAN Communication Signal ChartINFOID:0000000001374971
The CAN communication signal chart lists the signals needed for trouble diagnosis. It is useful for detecting
the root cause by finding a signal related to the sy
mptom, and by checking transmission and reception unit.
To o l U s a g e
Interview sheet For filling in vehicle information and interview with customer.
Data sheet For copying on-board diagnosis data.
Diagnosis sheet For detecting the root cause. (Diagnosis sheet includes system diagram for every CAN system type)
ECU list
(On the “CAN DIAG SUPPORT
MNTR”) For checking the condition of control units and the status of CAN communication.
SELF-DIAG RESULTS
(CONSULT-III)
CAN DIAG SUPPORT MNTR
(CONSULT-III)
CAN communication signal
chart For converting information received from a customer into CAN communication signal transmission
and reception. This information can be used to judge whether a circuit between control units is nor-
mal or abnormal.
Abbreviation list For checking abbreviations in CAN communication signal chart and diagnosis sheet.
SKIB8715E
Revision: March 2010 2008 QX56

LAN-18
< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
Interview Sheet (Example)
COLLECT DATA
Collect CONSULT-III Data
Print out or save the following CONSULT-III data.
• SELF-DIAG RESULTS
• CAN DIAG SUPPORT MNTR (“ECU list” included)
NOTE:
PKID1211E
Revision: March 2010
2008 QX56

LAN-20
< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
For some models, CAN communication diagnosis result is
received from the vehicle monitor. (CONSULT-III is
not available.)
CREATE DIAGNOSIS SHEET
NOTE:
Be sure to use the diagnosis sheet for the correct CAN system type.
Print Diagnosis Sheet
Print the diagnosis sheet for the applicable CAN system type.
Check Collected Data
Make sure that all ECUs are received, referring to “ECU list”.
SKIB8722E
Revision: March 2010 2008 QX56

LAN-22
< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
Identify the error circuit using information from t
he “CAN DIAG SUPPORT MNTR” (“ECU list” included).
1. ECU list: Check the items indicated in “ECU list”. Draw a line on the diagnosis sheet to indicate the error circuit.
NOTE:
CAN communication line has no error if units other than Diag on CAN units are not indicated. An error
may be on the power supply of the control unit, DDL1 line or DDL2 line.
a. “TCM” which is Diag on CAN unit, is not indicated on “E CU list”. This indicates that DLC is not receiving a
signal from TCM. Draw a line to indicate an error between DLC and TCM (line 1-a in the figure below).
NOTE:
• Diag on CAN units are not indicated on the “ECU list” when the CAN line between Diag on CAN unit and
the data link connector is open.
• For a description of Diag on CAN, refer to LAN-6, "
Description".
2. CAN DIAG SUPPORT MNTR: Check each item on “CAN DIAG SUPPORT MNTR”. Draw a line on the diagnosis sheet to indicate the error circuit.
a. Reception item of “ECM”: On “TCM”, “UNKWN” is indicated. This means ECM cannot receive the signal
from TCM. Draw a line to indicate an error between ECM and TCM (line 2-a in the figure below).
NOTE:
If “UNKWN” is indicated on “TRA NSMIT DIAG”, then the control uni t cannot transmit CAN communication
signal to each unit. Draw a line between the control unit and the splice.
b. Reception item of “AFS”: On “T CM”, “UNKWN” is indicated. This means AFS cannot receive the signal
from TCM. Draw a line to indicate an error between AFS and TCM (line 2-b in the figure below).
PKID1214E
Revision: March 2010 2008 QX56

LAN
DIAGNOSIS AND REPAIR WORKFLOWLAN-27
< BASIC INSPECTION > [CAN FUNDAMENTAL]
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5. Perform the inspection for the detected error circui
t. For the inspection procedure, refer to “MALFUNC-
TION AREA CHART”.
Present Error — Short Circuit —
When the symptoms listed below exist, a short circui t of the CAN communication line is a possible cause.
Received data
Error symptom• Most the units connected to the CAN communication system go into fail-safe mode or are deactivated.
Inspection procedure
PKID1219E
Item (CONSULT-III) Indication
ECU list (on the CAN DIAG SUPPORT MNTR) A ll Diag on CAN units are not indicated.
CAN DIAG SUPPORT MNTR “UNKWN” is indicated under “TRANSMIT DIAG” and most reception items.
Revision: March 2010 2008 QX56

LAN-36
< HOW TO USE THIS MANUAL >[CAN]
HOW TO USE THIS SECTION
HOW TO USE THIS MANUAL
HOW TO USE THIS SECTION
CautionINFOID:0000000001282378
• This section describes information pecul
iar to a vehicle and inspection procedures.
• For trouble diagnosis procedure, refer to LAN-14, "
Trouble Diagnosis Procedure".
Abbreviation ListINFOID:0000000001282379
Unit name abbreviations in CONSULT-III CAN diagnosis and in this section are as per the following list.
AbbreviationUnit nameSELECT SYSTEM
(CONSULT-III) CAN DIAG SUPPORT MNTR
(CONSULT-III)
4WD Transfer control unit ALL MODE AWD/4WDAWD/4WD
A-BAG Air bag diagnosis sensor unit AIR BAG—
ABS ABS actuator and electric unit (control unit) ABSVDC/TCS/ABS
ADP Driver seat control unit AUTO DRIVE POS.—
AV AV c o n t r o l u n i t M U LT I AVD I S P L AY
BCM BCM BCMBCM/SEC
DLC Data link connector ——
ECM ECM ENGINEECM
HVAC A/C auto amp. HVAC—
ICC ICC unit ICCICC
ICC/e4WD
I-KEY Intelligent Key unit INTELLIGENT KEYI-KEY
IPDM-E IPDM E/R IPDM E/RIPDM E/R
LASER ICC sensor —ICC SENSOR
M&A Combination meter METERMETER/M&A
STRG Steering angle sensor —STRG
TCM TCM A/TTCM
Revision: March 2010 2008 QX56

LAN-62
< COMPONENT DIAGNOSIS >[CAN]
MAIN LINE BETWEEN TCM AND ADP CIRCUIT
• Decision of CAN system type.
• Not received CONSULT-III data [SELF-DIAG RESULTS, CAN DIAG SUPPORT MNTR (“ECU
list” included)].
• Procedure for detecting root cause.
YES (Past error)>>Error was detected in the main line between the TCM and the driver seat control unit.
NO >> Repair the main line between the harness connectors B40 and B37.
Revision: March 2010 2008 QX56