Infiniti FX35 / FX45. Manual - part 761

TROUBLE DIAGNOSES WORK FLOW

LAN-21

< SERVICE INFORMATION >

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

L

M

A

B

LAN

N

O

P

• 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 —

PKID1213E

LAN-22

< SERVICE INFORMATION >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSES WORK FLOW

Identify the error circuit using information from the “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 “ECU 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-5, "Diag on CAN"

.

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 “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 “AFS”: 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).

PKID1214E

TROUBLE DIAGNOSES WORK FLOW

LAN-23

< SERVICE INFORMATION >

[CAN FUNDAMENTAL]

C

D

E

F

G

H

I

J

L

M

A

B

LAN

N

O

P

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 receiving units. Do not draw any line.
NOTE:

PKID1215E

LAN-24

< SERVICE INFORMATION >

[CAN FUNDAMENTAL]

TROUBLE DIAGNOSES WORK FLOW

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-39,

"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).

PKID1216E