INFINITI QX56 2011 Factory Service Manual

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TROUBLE DIAGNOSISLAN-11
< SYSTEM DESCRIPTION > [CAN FUNDAMENTAL]
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TROUBLE DIAGNOSIS
Condition of Error DetectionINFOID:0000000006220517
DTC of CAN communication is indicated on SELF-DIA
G RESULTS on CONSULT-III if a CAN communication
signal is not transmitted or received between units for 2 seconds or more.
NOTE:
DTCs of CAN communication are as follows:
 U0101
 U0140
 U0164
 U1000
 U1001
 U1507
 U1508
CAN COMMUNICATION SYSTEM ERROR
 CAN communication line open (CAN-H, CAN-L, or both)
 CAN communication line short (ground, betw een CAN communication lines, other harnesses)
 Error of CAN communication control circuit of the unit connected to CAN communication line
WHEN DTC OF CAN COMMUNICATION IS I NDICATED EVEN THOUGH CAN COMMUNICATION
SYSTEM IS NORMAL
 Removal/installation of parts: Error may be detec ted when removing and installing CAN communication unit
and related parts while turning the ignition switch ON. (A DTC except for CAN communication may be
detected.)
 Fuse blown out (removed): CAN communication of the unit may cease.
 Voltage drop: Error may be detected if voltage drops due to discharged battery when turning the ignition
switch ON (Depending on the control unit which carries out CAN communication).
 Error may be detected if the power supply circuit of the control unit, which carries out CAN communication,
malfunctions (Depending on the control unit which carries out CAN communication).
 Error may be detected if reprogramming is not completed normally.
CAUTION:
CAN communication system is normal if DTC of CAN communication is indicated on SELF-DIAG
RESULTS of CONSULT-III under th e above conditions. Erase the memo ry of the self-diagnosis of each
unit.
Symptom When Error Occurs in CAN Communication SystemINFOID:0000000006220518
In CAN communication system, multiple units mutually transmit and receive signals. Each unit cannot transmit
and receive signals if any error occurs on CAN communicati on line. Under this condition, multiple control units
related to the root cause malfunction or go into fail-safe mode.
ERROR EXAMPLE
NOTE:
 Each vehicle differs in symptom of each unit under fail-safe mode and CAN communication line wiring.
 Refer to LAN-23, "
Abbreviation List" for the unit abbreviation.
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LAN-12
< SYSTEM DESCRIPTION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSIS
Example: TCM branch line open circuit
Example: Data link connector branch line open circuit
SKIB8738E
Unit name Major symptom
ECM Engine torque limiting is affected, and shift harshness increases.
BCM Reverse warning chime does not sound.
EPS control unit No rmal operation.
Combination meter  Shift position indicator and OD OFF indicator turn OFF.
 Warning lamps turn ON.
ABS actuator and electric unit (control unit) Normal operation.
TCM No impact on operation.
IPDM E/R Normal operation.
SKIB8739E
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< SYSTEM DESCRIPTION > [CAN FUNDAMENTAL]
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NOTE:
 When data link connector branch line is open, transmi
ssion and reception of CAN communication signals
are not affected. Therefore, no symptoms occur. However, be sure to repair malfunctioning circuit.
 The model (all units on CAN communication system are Diag on CAN) cannot perform CAN diagnosis with
CONSULT-III if the following error occurs. The error is judged by the symptom.
Example: Main Line Between Data Link Connector and ABS Actuator and Electr ic Unit (Control Unit) Open Circuit
Unit name Major symptom
ECM
Normal operation.
BCM
EPS control unit
Combination meter
ABS actuator and electric
unit (control unit)
TCM
IPDM E/R
Error Difference of symptom
Data link connector branch line open circuit Normal operation.
CAN-H, CAN-L harness short-circuit Most of the units which are connected to the CAN communication
system enter fail-safe mode or are deactivated.
SKIB8740E
Unit name Major symptom
ECM Engine torque limiting is affected, and shift harshness increases.
BCM  Reverse warning chime does not sound.
 The front wiper moves under continuous operation mode even though the front wip-
er switch being in the intermittent position.
EPS control unit The steering effort increases.
Combination meter  The shift position indicator and OD OFF indicator turn OFF.
 The speedometer is inoperative.
 The odo/trip meter stops.
ABS actuator and electric unit (control unit) Normal operation.
TCM No impact on operation.
IPDM E/R When the ignition switch is ON,
 The headlamps (Lo) turn ON.
 The cooling fan continues to rotate.
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LAN-14
< SYSTEM DESCRIPTION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSIS
Example: CAN-H, CAN-L Harness Short Circuit
CAN Diagnosis with CONSULT-IIIINFOID:0000000006220519
CAN diagnosis on CONSULT-III extracts the root
cause by receiving the following information.
 Response to the system call
 Control unit diagnosis information
 Self-diagnosis
 CAN diagnostic support monitor
SKIB8741E
Unit name Major symptom
ECM  Engine torque limiting is affected, and shift harshness increases.
 Engine speed drops.
BCM  Reverse warning chime does not sound.
 The front wiper moves under continuous operation mode even though the front
wiper switch being in the intermittent position.
 The room lamp does not turn ON.
 The engine does not start (if an error or malfunction occurs while turning the igni- tion switch OFF.)
 The steering lock does not release (if an error or malfunction occurs while turning the ignition switch OFF.)
EPS control unit The steeri ng effort increases.
Combination meter  The tachometer and the speedometer do not move.
 Warning lamps turn ON.
 Indicator lamps do not turn ON.
ABS actuator and electric unit (control unit) Normal operation.
TCM No impact on operation.
IPDM E/R When the ignition switch is ON,
 The headlamps (Lo) turn ON.
 The cooling fan continues to rotate.
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< SYSTEM DESCRIPTION > [CAN FUNDAMENTAL]
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Self-DiagnosisINFOID:0000000006220520
CAN Diagnostic Support MonitorINFOID:0000000006220521
MONITOR ITEM (CONSULT-III)
Example: CAN DIAG SUPPORT MNTR indication
Without PAST
DTC
Self-diagnosis item
(CONSULT-III indication) DTC detection condition Inspection/Action
U0101 LOST COMM (TCM) When ECM is not transmitting or receiving CAN communi-
cation signal of OBD (emission-related diagnosis) from
TCM for 2 seconds or more.
Start the inspection. Re-
fer to the applicable sec-
tion of the indicated
control unit.
U0140 LOST COMM (BCM)
When ECM is not transmitting or receiving CAN communi-
cation signal of OBD (emission-related diagnosis) from
BCM for 2 seconds or more.
U0164 LOST COMM (HVAC) When ECM is not transmitting or receiving CAN communi-
cation signal of OBD (emission-related diagnosis) from A/
C auto amp. or unified meter and A/C amp. for 2 seconds
or more.
U1000 CAN COMM CIRCUIT ECM
When ECM is not transmitting or receiving CAN
communication signal of OBD (emission-relat-
ed diagnosis) for 2 seconds or more.
Except
for ECM When a control unit (except for ECM) is not
transmitting or receiving CAN communication
signal for 2 seconds or more.
U1001 CAN COMM CIRCUIT When ECM is not transmitting or receiving CAN communi-
cation signal other than OBD (emission-related diagnosis)
for 2 seconds or more.
U1002 SYSTEM COMM When a control unit is not transmitting or receiving CAN
communication signal for 2 seconds or less.
U1010 CONTROL UNIT(CAN) When an error is detected during the initial diagnosis for
CAN controller of each control unit. Replace the control unit
indicating “U1010” or
“P0607”.
P0607 ECM
U1507 LOST COMM (SIDE RDR R) When ADAS control unit is not receiving CAN communica-
tion signal from side radar RH for 2 seconds or more. Start the inspection. Re-
fer to the applicable sec-
tion of the indicated
control unit.
U1508 LOST COMM (SIDE RDR L) When ADAS control unit is not receiving CAN communica-
tion signal from side radar LH for 2 seconds or more.
JSMIA0015GB
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LAN-16
< SYSTEM DESCRIPTION >[CAN FUNDAMENTAL]
TROUBLE DIAGNOSIS
With PAST
MONITOR ITEM (ON-BOARD DIAGNOSIS)
NOTE:
For some models, CAN communication diagnosis result is received from the vehicle monitor.
Example: Vehicle Display
Item PRSNT Description
Initial diagnosis OK Normal at present
NG Control unit error (Excep t for some control units)
Transmission diagnosis OK Normal at present
UNKWN Unable to transmit signals for 2 seconds or more.
Diagnosis not performed
Control unit name
(Reception diagnosis) OK Normal at present
UNKWN Unable to receive signals for 2 seconds or more.
Diagnosis not performed
No control unit for receiving signals. (No applicable optional parts)
Item PRSNT PAST Description
Transmission diagnosis OKOK Normal at present and in the past
1 – 39 Normal at present, but unable to transmit signals for 2 seconds or more
in the past. (The number indicates the number of ignition switch cycles
from OFF to ON.)
UNKWN 0 Unable to transmit signals for 2 seconds or more at present.
Control unit name
(Reception diagnosis) OK
OK Normal at present and in the past
1 – 39 Normal at present, but unable to receive signals for 2 seconds or more
in the past. (The number indicates the number of ignition switch cycles
from OFF to ON.)
UNKWN 0 Unable to receive signals for 2 seconds or more at present.
–– Diagnosis not performed.
No control unit for receiving signals. (No applicable optional parts)
Item
Result indi-
cated Error counter Description
CAN_COMM
(Initial diagnosis) OK 0 Normal at present
NG 1 – 50 Control unit error
(The number indicates how many times diagnosis has been
run.)
CAN_CIRC_1
(Transmission diagnosis) OK 0 Normal at present
UNKWN 1 – 50 Unable to transmit for 2 seconds or more at present.
(The number indicates how many times diagnosis has been
run.)
CAN_CIRC_2 – 9
(Reception diagnosis of each unit) OK 0 Normal at present
UNKWN 1 – 50 Unable to transmit for 2 seconds or more at present.
(The number indicates how many times diagnosis has been
run.)
Diagnosis not performed.
No control unit for receiving signals. (No applicable optional
parts)
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How to Use CAN Communication Signal ChartINFOID:0000000006220522
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.
SKIB8715E
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LAN-18
< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Trouble Diagnosis Flow ChartINFOID:0000000006220523
Trouble Diagnosis ProcedureINFOID:0000000006220524
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
 Result: Symptom
NOTE:
 Check normal units as well as error symptoms.
- Example: Circuit between ECM and the combination me ter 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.
JSMIA0016GB
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LAN
DIAGNOSIS AND REPAIR WORKFLOWLAN-19
< BASIC INSPECTION > [CAN FUNDAMENTAL]
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 Indication of the combination meter is important to det
ect the root cause because it is the most obvious to
the customer, and it performs CA N communication with many units.
INSPECTION OF VEHICLE CONDITION
Check whether the symptom is reproduced or not.
NOTE:
Do not turn the ignition switch OFF or disconnect the bat tery cable while reproducing the error. The error may
temporarily correct itself, making it difficult to determine the root cause.
CHECK OF CAN SYSTEM TYPE (HOW TO US E CAN SYSTEM TYPE SPECIFICATION CHART)
Determine CAN system type based on vehicle equipment.
NOTE:
 This chart is used if CONSULT-III does not automatically recognize CAN system type.
 There are two styles for CAN system type specificat ion charts. Depending on the number of available sys-
tem types, either style A or style B may be used.
CAN System Type Specification Chart (Style A)
NOTE:
SKIB8717E
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< BASIC INSPECTION >[CAN FUNDAMENTAL]
DIAGNOSIS AND REPAIR WORKFLOW
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:
JSMIA0017GB
Revision: 2010 May2011 QX56