INFINITI QX56 2008 Factory Service Manual

LAN-16
< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
CAN system type is easily checked with the vehicle equi
pment identification information shown in the chart.
CAN System Type Specification Chart (Style B)
NOTE:
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CAN system type is easily checked wi
th the vehicle equipment identification information shown in the chart.
CREATE INTERVIEW SHEET
Fill out the symptom described by the customer, vehicle condition, and CAN system type on the interview
sheet.
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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:
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Some items may not be needed depending on CAN system type of vehicle.
Create On-board Diagnosis Copy Sheet
Display the trouble diagnosis result of CAN communica
tion with the on-board diagnosis function on the vehicle
monitor, etc. Copy them on the on-board diagnosis copy sheet.
NOTE:
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< 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”.
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• For abbreviations, refer to
LAN-36, "Abbreviation List".
DETECT THE ROOT CAUSE
Identify the root cause using the created diagnosis sheet.
Identifying the root cause• Draw a line on the diagnosis sheet to indicate the possible cause. Narrow the search.
NOTE:
• Color-code when drawing lines.
• Do not draw a line onto a existing line.
• Drawing a line is not necessary if the circuit is shorted. Refer to “Present Error — Short Circuit —”, “Past Error — Short Circuit —”.
Refer to the following for details of the trouble diagnosis procedure.
• “Present Error — Open Circuit —”
• “Present Error — Short Circuit —”
• “Past Error — Open Circuit —”
• “Past Error — Short Circuit —”
NOTE:
When the root cause appears to be a branch line or short circuit, be sure to check the control unit as well as
the communication line.
Present Error — Open Circuit —
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< 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).
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c. Reception item of “AV”: “UNKWN” is not indicated. This indicates normal communication between AV and
its receiving units. Do not draw any line.
d. Reception item of “BCM”: On “TCM”, “UNKWN” is indicated. This means BCM cannot receive the signal from TCM. Draw a line to indicate an error between BCM and TCM (line 2-d in the figure below).
e. Reception item of “EPS” and “I-KEY”: “UNKWN” is not indicated. This indicates normal communication between EPS and I-KEY and their receiv ing units. Do not draw any line.
NOTE:
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< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
On CAN DIAG SUPPORT MNTR (without PAST), “UNK
WN” is indicated even though the item is not used
in the trouble diagnosis. For the details of each item on CAN diagnostic support monitor, refer to LAN-47,
"CAN Diagnostic Support Monitor".
f. Reception item of “M&A”: On “TCM”, “UNKWN” is indicated. This means M&A cannot receive the signal
from TCM. Draw a line to indicate an error between M&A and TCM (line 2-f in the figure below).
g. Reception item of “ADP”: On “TCM”, “UNKWN” is indicated. This means ADP cannot receive the signal
from TCM. Draw a line to indicate an error between ADP and TCM (line 2-g in the figure below).
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h. Reception item of “ABS”: “UNKWN” is not indicated. This indicates normal communication between ABS
and its receiving units. Do not draw any line.
i. Reception item of “IPDM-E”: “UNKWN” is not indicated. This indicates normal communication between IPDM-E and its receiving units. Do not draw any line.
3. Based on information received from “CAN DIAG SUPPORT MNTR”, place a check mark on the known good CAN communication line between ECM and IPDM-E.
a. Through the previous procedure, the circuit betw een ADP splice and TCM has the most amount of lines
(shade 3-a in the figure below).
b. Place a check mark on the known good lines to establish the error circuit.
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