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Trouble Diagnosis Flow Chart
INFOID:0000000003533617
Trouble Diagnosis ProcedureINFOID:0000000003533618
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: Circ INFINITI QX56 2007 Factory Service Manual TROUBLE DIAGNOSES WORK FLOW
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• Result: Symptom
NOTE:
• Check normal units as well as error symptoms.
- Example: Circ](/manual-img/42/57029/w960_57029-2145.png)
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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 from
the customer, and it performs CAN communication with many units.
INSPECTION OF VEHICLE CONDITION
• Check whether or not “U1000” or “U1001” is indicated on “SELF-DIAG RESULTS” by CONSULT-II.
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:
• Never turn the ignition switch OFF or disconnect the battery cable while the 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 equipment. Then choose the correct diagnosis sheet.
NOTE:
There are two styles for CAN system type specification 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 equipment identification information shown in the chart.
CAN System Type Specification Chart (Style B)
NOTE:
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CAN system type is easily checked with 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)
CREATE DATA SHEET
Create CONSULT-II Data Attachment Sheet
Print out the following CONSULT-II screens, and attach them to the CONSULT-II data attachment sheet.
• SELECT SYSTEM
• SELF-DIAG RESULTS
• CAN DIAG SUPPORT MNTR
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 communication with the on-board diagnosis function on the vehicle
monitor, etc. Copy them on the on-board diagnosis copy sheet.
NOTE:
• For some models, CAN communication diagnosis result is received from the vehicle monitor. (CONSULT-II
is not available.)
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• For the details, refer to LAN-54, "Data Sheet".
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 of Received Data
Check the created data sheet for missing information.
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• For abbreviations, refer to LAN-37, "Abbreviation List".
DETECT THE ROOT CAUSE
Identify INFINITI QX56 2007 Factory Service Manual TROUBLE DIAGNOSES WORK FLOW
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• For abbreviations, refer to LAN-37, "Abbreviation List".
DETECT THE ROOT CAUSE
Identify](/manual-img/42/57029/w960_57029-2151.png)
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• For abbreviations, refer to LAN-37, "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 —
Identify the error circuit using information from the “SELECT SYSTEM” and “CAN DIAG SUPPORT MNTR”
screens.
1. SELECT SYSTEM: Check the items indicated in “SELECT SYSTEM”. 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 indicated. An error may be
on the power supply of the control unit, DDL1 line or DDL2 line.
a. “TRANSMISSION” which is Diag on CAN unit, is not indicated on “SELECT SYSTEM” screen. This indi-
cates 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).
NOTE:
• Diag on CAN units are not indicated on the “SELECT SYSTEM” screen when the CAN line between
Diag on CAN unit and the data link connector is open.
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