Nissan Pathfinder (2012 year). Manual - part 449

LAN-20

< BASIC INSPECTION >

[CAN FUNDAMENTAL]

DIAGNOSIS AND REPAIR WORKFLOW

For some models, CAN communication diagnosis result is received from the vehicle monitor. (CONSULT 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

Check that all ECUs are received, referring to “system” displayed in “ALL DTC.”

NOTE:

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DIAGNOSIS AND REPAIR WORKFLOW

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[CAN FUNDAMENTAL]

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For abbreviations, refer to 

LAN-36, "Abbreviation List"

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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 —

JSMIA0811GB

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< BASIC INSPECTION >

[CAN FUNDAMENTAL]

DIAGNOSIS AND REPAIR WORKFLOW

Identify the error circuit using information from the “CAN DIAG SUPPORT MNTR”
1. Check the items indicated in “ALL DTC”. 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 “ALL DTC.” 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 “ALL DTC” 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"

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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 “ENGINE”: On “TCM”, “UNKWN” is indicated. This means ECM cannot receive the sig-

nal 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 “TRANSMIT DIAG”, then the control unit cannot transmit CAN communication

signal to each unit. Draw a line between the control unit and the splice.

b. Reception item of “ADAPTIVE LIGHT”: On “TCM”, “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).

JSMIA0813GB

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DIAGNOSIS AND REPAIR WORKFLOW

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c. Reception item of “MULTI 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 “INTELLIGENT KEY”: “UNKWN” is not indicated. This indicates normal com-

munication between EPS and I-KEY and their receiving units. Do not draw any line.

NOTE:

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[CAN FUNDAMENTAL]

DIAGNOSIS AND REPAIR WORKFLOW

On CAN DIAG SUPPORT MNTR (without PAST), “UNKWN” 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-56,

"CAN Diagnostic Support Monitor"

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f.

Reception item of “METER/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 “AUTO DRIVE POS.”: 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).

JSMIA0815GB

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DIAGNOSIS AND REPAIR WORKFLOW

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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/R”: “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 between 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.

JSMIA0816GB

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< BASIC INSPECTION >

[CAN FUNDAMENTAL]

DIAGNOSIS AND REPAIR WORKFLOW

Reception item of “IPDM E/R”: On “ECM”, “OK” is indicated. IPDM-E communicates normally with ECM.

Put a check mark on the normal circuit between ECM and IPDM-E (check mark 3-b in the figure below).

4. Through the above procedure, the error is detected in the TCM branch line (shaded in the figure below).

NOTE:

For abbreviations, refer to 

LAN-36, "Abbreviation List"

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JSMIA0817GB

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DIAGNOSIS AND REPAIR WORKFLOW

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5. Perform the inspection for the detected error circuit. For the inspection procedure, refer to “MALFUNC-

TION AREA CHART”. 

Present Error — Short Circuit —

When the symptoms listed below exist, a short circuit 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)

Indication

SELF-DIAG RESULTS

All Diag on CAN units are not indicated.

CAN DIAG SUPPORT MNTR

“UNKWN” is indicated under “TRANSMIT DIAG” and most reception items.

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