INFINITI QX56 2010 Factory Service Manual

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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Information Needed for Trouble DiagnosisINFOID:0000000005146448
CAN communication system performs trouble diagnosis with the following tools.
How to Use CAN Communication Signal ChartINFOID:0000000005146449
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.
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Trouble Diagnosis Flow Chart
INFOID:0000000005146450
Trouble Diagnosis ProcedureINFOID:0000000005146451
INTERVIEW WITH CUSTOMER
Interview with the customer is important to detect the root cause of CAN communication system errors and to
understand vehicle condition and symptoms for proper trouble diagnosis.
Points in interview• What: Parts name, system name
• When: Date, Frequency
• Where: Road condition, Place
• In what condition: Driving condition/environment
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• Result: Symptom
NOTE:
• Check normal units as well as error symptoms.
- Example: Circuit between ECM and the combination meter is judged normal if the customer indicates
tachometer functions normally.
• When a CAN communication system error is present, multiple control units may malfunction or go into fail-
safe mode.
• Indication of the combination meter is important to detect the root cause because it is the most obvious to
the customer, and it performs CAN communication with many units.
INSPECTION OF VEHICLE CONDITION
• Check whether or not “U1000” or “U1001” is indi cated on “SELF-DIAG RESULTS” by CONSULT-III.
NOTE:
Root cause cannot be detected using the procedure in this section if “U1000” or “U1001” is not indicated.
• Check whether the symptom is reproduced or not.
NOTE:
• Do not turn the ignition switch OFF or disconnect the battery cable while reproducing the error. The error may temporarily correct itself, making it difficult to determine the root cause.
• The procedures for present errors differ from the procedures for past errors. Refer to “DETECT THE ROOT CAUSE”.
CHECK OF CAN SYSTEM TYPE (HOW TO USE CAN SYSTEM TYPE SPECIFICATION CHART)
Determine CAN system type based on vehicle equipm ent. Then choose the correct diagnosis sheet.
NOTE:
There are two styles for CAN system type specificat ion charts. Depending on the number of available system
types, either style A or style B may be used.
CAN System Type Specification Chart (Style A)
NOTE:
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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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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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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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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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