Can communication INFINITI QX56 2004 Factory Service Manual

LAN-50
[CAN]
CAN SYSTEM (TYPE 2)
Revision: August 20072004 QX56
CAN SYSTEM (TYPE 2)PFP:23710
System DescriptionUKS001N3
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Component Parts and Harness Connector LocationUKS001N4
BKIA0119E

CAN SYSTEM (TYPE 2)
LAN-55
[CAN]
C
D
E
F
G
H
I
J
L
MA
B
LAN
Revision: August 20072004 QX56
Work FlowUKS001N7
1. When there are no indications of “AUTO DRIVE POS.”, “BCM” or “IPDM E/R” on “SELECT SYSTEM” dis-
play of CONSULT-II, print the “SELECT SYSTEM”.
2. Print all the data of “SELF-DIAG RESULTS” for “ENGINE”, “A/T”, “ICC”, “AUTO DRIVE POS.”, “BCM”,
“ABS” and “IPDM E/R” displayed on CONSULT-II.
3. Print all the data of “CAN DIAG SUPPORT MNTR” for “ENGINE”, “A/T”, “ICC”, “AUTO DRIVE POS.”,
“BCM”, “ABS” and “IPDM E/R” displayed on CONSULT-II.
4. Attach the printed sheet of “SELECT SYSTEM”, “SELF-DIAG RESULTS” and “CAN DIAG SUPPORT
MNTR” onto the check sheet. Refer to LAN-57, "
CHECK SHEET" .
5. Based on the indications of “SELECT SYSTEM” and the results of “CAN DIAG SUPPORT MNTR”, put
marks “v” onto the items with “No indication”, “NG” or “UNKWN” in the check sheet table. Refer to LAN-57,
"CHECK SHEET" .
NOTE:

If “NG” is displayed on “INITIAL DIAG (Initial diagnosis)” as “CAN DIAG SUPPORT MNTR” for the diag-
nosed control unit, replace the control unit.

The “CAN DIAG SUPPORT MNTR” items, which are not in check sheet table, are not related to diag-
nostic procedure on service manual.
So it is not necessary to check the status of the “CAN DIAG SUPPORT MNTR” items not in check
sheet table.
6. Check CAN communication line of the navigation system. Refer to AV-131, "
CAN Communication Line
Check" .
7. Attach the CAN DIAG SUPPORT MONITOR check sheet onto the check sheet. Refer to LAN-57,
"CHECK SHEET" .
PKIA2093E
PKIA8260E
PKIA8343E

LAN-56
[CAN]
CAN SYSTEM (TYPE 2)
Revision: August 20072004 QX56
8. Mark the “NG” or “UNKWN” item of the check sheet table with “v” from the result of CAN DIAG SUPPORT
MONITOR check sheet. Refer to LAN-57, "
CHECK SHEET" .
NOTE:
If “NG” is displayed on “CAN COMM” as “CAN DIAG SUPPORT MONITOR” for the diagnosed control
unit, replace the control unit. Refer to AV- 1 3 1 , "
CAN Communication Line Check" .
9. According to the check sheet results (example), start inspection. Refer to LAN-59, "
CHECK SHEET
RESULTS (EXAMPLE)" .

CAN SYSTEM (TYPE 2)
LAN-77
[CAN]
C
D
E
F
G
H
I
J
L
MA
B
LAN
Revision: August 20072004 QX56
Case 19
Check CAN communication circuit. Refer to LAN-88, "CAN Communication Circuit Check" .
Case 20
Check IPDM E/R ignition relay circuit continuously sticks “OFF”. Refer to LAN-89, "IPDM E/R Ignition Relay
Circuit Check" .
PKIA8107E
PKIA8108E

LAN-88
[CAN]
CAN SYSTEM (TYPE 2)
Revision: August 20072004 QX56
IPDM E/R Circuit CheckUKS001NL
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Check terminals and connector of IPDM E/R for damage, bend and loose connection (control module side
and harness side).
OK or NG
OK >> GO TO 2.
NG >> Repair terminal or connector.
2. CHECK HARNESS FOR OPEN CIRCUIT
1. Disconnect IPDM E/R connector.
2. Check resistance between IPDM E/R harness connector E122
terminals 39 (W) and 40 (R).
OK or NG
OK >> Replace IPDM E/R.
NG >> Repair harness between IPDM E/R and harness con-
nector E152.
CAN Communication Circuit CheckUKS001NM
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Disconnect the following module and control unit connectors and check terminals for deformation, discon-
nection, looseness or damage.
–ECM
–A/T assembly
–ICC sensor
–ICC unit
–Driver seat control unit
–Combination meter
–Display control unit
–BCM
–Steering angle sensor
–Front air control
–ABS actuator and electric unit (control unit)
–IPDM E/R
OK or NG
OK >> GO TO 2.
NG >> Repair or replace as necessary.39 (W) - 40 (R) : Approx. 108 - 132Ω
PKIA8141E

LAN-90
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
CAN SYSTEM (TYPE 3)PFP:23710
System DescriptionUKS000QY
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Component Parts and Harness Connector LocationUKS000QZ
BKIA0120E

CAN SYSTEM (TYPE 3)
LAN-95
[CAN]
C
D
E
F
G
H
I
J
L
MA
B
LAN
Revision: August 20072004 QX56
Work FlowUKS0019V
1. When there are no indications of “AUTO DRIVE POS.”, “BCM” or “IPDM E/R” on “SELECT SYSTEM” dis-
play of CONSULT-II, print the “SELECT SYSTEM”.
2. Print all the data of “SELF-DIAG RESULTS” for “ENGINE”, “A/T”, “AUTO DRIVE POS.”, “BCM”, “ALL
MODE AWD/4WD”, “ABS” and “IPDM E/R” displayed on CONSULT-II.
3. Print all the data of “CAN DIAG SUPPORT MNTR” for “ENGINE”, “A/T”, “AUTO DRIVE POS.”, “BCM”,
“ALL MODE AWD/4WD”, “ABS” and “IPDM E/R” displayed on CONSULT-II.
4. Attach the printed sheet of “SELECT SYSTEM”, “SELF-DIAG RESULTS” and “CAN DIAG SUPPORT
MNTR” onto the check sheet. Refer to LAN-97, "
CHECK SHEET" .
5. Based on the indications of “SELECT SYSTEM” and the results of “CAN DIAG SUPPORT MNTR”, put
marks “v” onto the items with “No indication”, “NG” or “UNKWN” in the check sheet table. Refer to LAN-97,
"CHECK SHEET" .
NOTE:

If “NG” is displayed on “INITIAL DIAG (Initial diagnosis)” as “CAN DIAG SUPPORT MNTR” for the diag-
nosed control unit, replace the control unit.

The “CAN DIAG SUPPORT MNTR” items, which are not in check sheet table, are not related to diag-
nostic procedure on service manual.
So it is not necessary to check the status of the “CAN DIAG SUPPORT MNTR” items not in check
sheet table.
6. Check CAN communication line of the navigation system. Refer to AV-131, "
CAN Communication Line
Check" .
7. Attach the CAN DIAG SUPPORT MONITOR check sheet onto the check sheet. Refer to LAN-97,
"CHECK SHEET" .
PKIA2093E
PKIA8260E
PKIA8343E

LAN-96
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
8. Mark the “NG” or “UNKWN” item of the check sheet table with “v” from the result of CAN DIAG SUPPORT
MONITOR check sheet. Refer to LAN-97, "
CHECK SHEET" .
NOTE:
If “NG” is displayed on “CAN COMM” as “CAN DIAG SUPPORT MONITOR” for the diagnosed control
unit, replace the control unit. Refer to AV- 1 3 1 , "
CAN Communication Line Check" .
9. According to the check sheet results (example), start inspection. Refer to LAN-99, "
CHECK SHEET
RESULTS (EXAMPLE)" .

LAN-114
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
Case 16
Check CAN communication circuit. Refer to LAN-124, "CAN Communication Circuit Check" .
Case 17
Check IPDM E/R ignition relay circuit continuously sticks “OFF”. Refer to LAN-124, "IPDM E/R Ignition Relay
Circuit Check" .
PKIA8084E
PKIA8085E

LAN-124
[CAN]
CAN SYSTEM (TYPE 3)
Revision: August 20072004 QX56
CAN Communication Circuit CheckUKS001AB
1. CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect the negative battery terminal.
3. Disconnect the following module and control unit connectors and check terminals for deformation, discon-
nection, looseness or damage.
–ECM
–A/T assembly
–Driver seat control unit
–Combination meter
–Display control unit
–BCM
–Steering angle sensor
–Front air control
–Transfer control unit
–ABS actuator and electric unit (control unit)
–IPDM E/R
OK or NG
OK >> GO TO 2.
NG >> Repair or replace as necessary.
2. CHECK HARNESS FOR SHORT CIRCUIT
With all module and control unit connectors disconnected, check
continuity between data link connector M22 terminals 6 (W) and 14
(R).
OK or NG
OK >> GO TO 3.
NG >> Repair harness.
3. CHECK HARNESS FOR SHORT CIRCUIT
Check continuity between data link connector M22 terminals 6 (W),
14 (R) and ground.
OK or NG
OK >> Check ECM and IPDM E/R. Refer to LAN-125, "ECM/
IPDM E/R INTERNAL CIRCUIT INSPECTION" .
NG >> Repair harness.
IPDM E/R Ignition Relay Circuit CheckUKS001AC
Check the following. If no malfunction is found, replace the IPDM E/R.

IPDM E/R power supply circuit. Refer to PG-27, "IPDM E/R Power/Ground Circuit Inspection" .

Ignition power supply circuit. Refer to PG-13, "IGNITION POWER SUPPLY — IGNITION SW. IN ON
AND/OR START" . 6 (W) - 14 (R) : Continuity should not exist.
PKIA2077E
6 (W) - Ground : Continuity should not exist.
14 (R) - Ground : Continuity should not exist.
PKIA2079E