2009 INFINITI QX56 100

MWI-28
< COMPONENT DIAGNOSIS >
DTC U1000 CAN COMMUNICATION
COMPONENT DIAGNOSIS
DTC U1000 CAN COMMUNICATION
DTC LogicINFOID:0000000003776628
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000003776629
Symptom: Displays “CAN COMM CIRC [U1000]” as a self-diagnosis result of combination meter.
1.CHECK CAN COMMUNICATION
Select “SELF-DIAG RESULTS” mode for “METER/M&A” with CONSULT-III.
>> Go to “LAN system”. Refer to LAN-14, "
Trouble Diagnosis Flow Chart".
DTC CONSULT-III display Detection condition
U1000 CAN COMM CIRC
[U1000] When combination meter is not receiving CAN communication signals for 2 seconds or more.
Revision: December 20092009 QX56

MWI-62
< ECU DIAGNOSIS >
COMBINATION METER
DTC Index
INFOID:0000000003776656
Function Specifications
Speedometer
Zero indication.
Tachometer
Fuel gauge
Engine coolant temperature gauge
Engine oil pressure gauge
Voltage gauge
A/T oil temperature gauge
Illumination control
Meter illumination Change to nighttime mode when communication is lost.
Segment LCD Odometer
Freeze current indication.
A/T position Display turns off.
Buzzer Buzzer turns off.
Warning lamp/indicator lamp ABS warning lamp
Lamp turns on when communication is lost.
Brake warning lamp
VDC OFF indicator lamp
SLIP indicator lamp
A/T CHECK warning lamp
Lamp turns off when communication is lost.
Oil pressure/coolant temperature
warning lamp
Light indicator
Malfunction indicator lamp
Master warning lamp
Air bag warning lamp
High beam indicator
Turn signal indicator lamp
CRUISE indicator lamp
Driver and passenger seat belt warn-
ing lamp
Lamp turns off when disconnected.
Charge warning lamp
Security indicator lamp
4WD indicator lamp
AT P i n d i c a t o r l a m p
CK SUSP warning lamp
Low tire pressure warning lamp
Lamp will flash every second for 1 minute and then stay on con-
tinuously thereafter.
CONSULT-III display
MalfunctionReference
page
CAN COMM CIRC
[U1000] Malfunction is detected in CAN communication.
CAUTION:
Even when there is no malfunction on CAN communication system, malfunction may be
misinterpreted when battery has low voltage (when maintaining 7 - 8 V for about 2 sec-
onds) or 10A fuse [No. 3, located in
the fuse block (J/B)] is disconnected. MWI-28
VEHICLE SPEED
CIRC
[B2205]Malfunction is detected when an erroneous speed signal is input.
CAUTION:
Even when there is no malfunction on speed signal system, malfunction may be misin-
terpreted when battery has lo
w voltage (when maintaining 7 - 8 V for about 2 seconds). MWI-29
Revision: December 20092009 QX56

MWI
BCM (BODY CONTROL MODULE)MWI-77
< ECU DIAGNOSIS >
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DTC Inspection Priority ChartINFOID:0000000004225400
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
DTC IndexINFOID:0000000004225401
NOTE: Details of time display
• CRNT: Displays when there is a malfunction now or after returning to the normal condition until turning igni-
tion switch OFF → ON again.
• 1 - 39: Displayed if any previous ma lfunction is present when current conditi on is normal. It increases like 1
→ 2 → 3...38 → 39 after returning to the normal condition whenever ignition switch OFF → ON. The counter
remains at 39 even if the number of cycles exceeds it. It is counted from 1 again when turning ignition switch
OFF → ON after returning to the normal condi tion if the malfunction is detected again.
Display contents of CONSULT Fail-safe Cancellation
U1000: CAN COMM CIRCUIT I nhibit engine crankingWhen the BCM re-establishes communication with the other mod-
ules.
U1010: CONTROL UNIT (CAN) Inhibit engine cranking When the BCM re-start communicating with the other modules.
Priority DTC
1 • U1000: CAN COMM CIRCUIT
• U1010: CONTROL UNIT (CAN)
2 • B2190: NATS ANTENNA AMP
• B2191: DIFFERENCE OF KEY
• B2192: ID DISCORD BCM-ECM
• B2193: CHAIN OF BCM-ECM
• B2013: STRG COMM 1
• B2552: INTELLIGENT KEY
• B2590: NATS MALFUNCTION
3 • C1729: VHCL SPEED SIG ERR
• C1735: IGNITION SIGNAL
4 • C1704: LOW PRESSURE FL
• C1705: LOW PRESSURE FR
• C1706: LOW PRESSURE RR
• C1707: LOW PRESSURE RL
• C1708: [NO DATA] FL
• C1709: [NO DATA] FR
• C1710: [NO DATA] RR
• C1711: [NO DATA] RL
• C1712: [CHECKSUM ERR] FL
• C1713: [CHECKSUM ERR] FR
• C1714: [CHECKSUM ERR] RR
• C1715: [CHECKSUM ERR] RL
• C1716: [PRESSDATA ERR] FL
• C1717: [PRESSDATA ERR] FR
• C1718: [PRESSDATA ERR] RR
• C1719: [PRESSDATA ERR] RL
• C1720: [CODE ERR] FL
• C1721: [CODE ERR] FR
• C1722: [CODE ERR] RR
• C1723: [CODE ERR] RL
• C1724: [BATT VOLT LOW] FL
• C1725: [BATT VOLT LOW] FR
• C1726: [BATT VOLT LOW] RR
• C1727: [BATT VOLT LOW] RL
Revision: December 20092009 QX56

MWI-78
< ECU DIAGNOSIS >
BCM (BODY CONTROL MODULE)
CONSULT displayFail-safeIntelligent Key
warning lamp ON Tire pressure
monitor warning lamp ON Reference page
No DTC is detected.
further testing
may be required. ————
U1000: CAN COMM CIRCUIT ———BCS-30
U1010: CONTROL UNIT (CAN) ———BCS-31
B2190: NATS ANTENNA AMP ———SEC-27
B2191: DIFFERENCE OF KEY ———SEC-30
B2192: ID DISCORD BCM-ECM ———SEC-31
B2193: CHAIN OF BCM-ECM ———SEC-33
B2552: INTELLIGENT KEY ———SEC-35
B2590: NATS MALFUNCTION ———SEC-36
C1704: LOW PRESSURE FL ———WT-26
C1705: LOW PRESSURE FR ———WT-26
C1706: LOW PRESSURE RR ———WT-26
C1707: LOW PRESSURE RL ———WT-26
C1708: [NO DATA] FL ———WT-14
C1709: [NO DATA] FR ———WT-14
C1710: [NO DATA] RR ———WT-14
C1711: [NO DATA] RL ———WT-14
C1712: [CHECKSUM ERR] FL ———WT-16
C1713: [CHECKSUM ERR] FR ———WT-16
C1714: [CHECKSUM ERR] RR ———WT-16
C1715: [CHECKSUM ERR] RL ———WT-16
C1716: [PRESSDATA ERR] FL ———WT-18
C1717: [PRESSDATA ERR] FR ———WT-18
C1718: [PRESSDATA ERR] RR ———WT-18
C1719: [PRESSDATA ERR] RL ———WT-18
C1720: [CODE ERR] FL ———WT-16
C1721: [CODE ERR] FR ———WT-16
C1722: [CODE ERR] RR ———WT-16
C1723: [CODE ERR] RL ———WT-16
C1724: [BATT VOLT LOW] FL ———WT-16
C1725: [BATT VOLT LOW] FR ———WT-16
C1726: [BATT VOLT LOW] RR ———WT-16
C1727: [BATT VOLT LOW] RL ———WT-16
C1729: VHCL SPEED SIG ERR ———WT-19
C1735: IGNITION SIGNAL ————
Revision: December 20092009 QX56

MWI
IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)
MWI-79
< ECU DIAGNOSIS >
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IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE
ROOM)
Reference ValueINFOID:0000000004225402
VALUES ON THE DIAGNOSIS TOOL
Monitor Item ConditionValue/Status
MOTOR FAN REQ Engine idle speed Changes depending on engine
coolant temperature, air conditioner
operation status, vehicle speed,
etc.0 - 100 %
A/C COMP REQ A/C switch OFF
OFF
A/C switch ON ON
TA I L & C L R R E Q Lighting switch OFF
OFF
Lighting switch 1ST, 2ND, HI or AUTO (Light is illuminated) ON
HL LO REQ Lighting switch OFF
OFF
Lighting switch 2ND HI or AUTO (Light is illuminated) ON
HL HI REQ Lighting switch OFF
OFF
Lighting switch HI ON
FR FOG REQ Lighting switch 2ND or AUTO (Light
is illuminated) Front fog lamp switch OFF OFF
• Front fog lamp switch ON
• Daytime light activated (Canada
only) ON
HL WASHER REQ NOTE:
This item is displayed, but cannot be monitored.
OFF
FR WIP REQ Ignition switch ON Front wiper switch OFF
STOP
Front wiper switch INT 1LOW
Front wiper switch LO LOW
Front wiper switch HI HI
WIP AUTO STOP Ignition switch ON Front wiper stop position
STOP P
Any position other than front wiper
stop position ACT P
WIP PROT Ignition switch ON Front wiper operates normally OFF
Front wiper stops at fail-safe opera-
tion
BLOCK
ST RLY REQ Ignition switch OFF or ACC
OFF
Ignition switch START ON
IGN RLY Ignition switch OFF or ACC
OFF
Ignition switch ON ON
RR DEF REQ Rear defogger switch OFF
OFF
Rear defogger switch ON ON
OIL P SW Ignition switch OFF, ACC or engine running
OPEN
Ignition switch ON CLOSE
DTRL REQ Daytime light system requested OFF with CONSULT-III.
OFF
Daytime light system reques ted ON with CONSULT-III. ON
HOOD SW Hood closed.
OFF
Hood open. ON
Revision: December 20092009 QX56

MWI
IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)
MWI-91
< ECU DIAGNOSIS >
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DTC IndexINFOID:0000000004225407
NOTE:
The details of TIME display are as follows.
• CRNT: The malfunctions that are detected now
• 1 - 39: The number is indicated when it is normal at present and a malfunction was detected in the past. It
increases like 0 → 1 → 2 ··· 38 → 39 after returning to the normal condition whenever IGN OFF → ON. It is
fixed to 39 until the self-diagnosis results are erased if it is over 39. It returns to 0 when a malfunction is
detected again in the process.
CONSULT-III display Fail-safe
TIMENOTERefer to
No DTC is detected.
further testing
may be required. ————
U1000: CAN COMM CIRCUIT ×CRNT 1 – 39 PCS-17
Revision: December 20092009 QX56

MWI-100
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005867495
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harn esses can be identified by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Unit or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or electri c power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers , always switch the Ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation After Battery Disconnect
INFOID:0000000005867496
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NATS (NISSAN ANTI-THEFT SYS-
TEM).
• Remove and install all control units after disconnecting both battery cables with the ignition knob in the
″LOCK ″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NATS, an electrically controlled steering lock mech-
anism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery pow er is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC ″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be rotated.
4. Perform the necessary repair operation.
Revision: December 20092009 QX56

PCS
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ELECTRICAL & POWER CONTROL
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CONTENTS
POWER CONTROL SYSTEM
IPDM E/R
BASIC INSPECTION ....... .............................
2
DIAGNOSIS AND REPAIR WORKFLOW ..... .....2
Work Flow ........................................................... ......2
FUNCTION DIAGNOSIS ...............................5
RELAY CONTROL SYSTEM ......................... .....5
System Diagram .................................................. ......5
System Description ...................................................6
Component Parts Location ........................................7
POWER CONTROL SYSTEM .............................8
System Diagram .................................................. ......8
System Description ...................................................8
SIGNAL BUFFER SYSTEM ................................9
System Diagram .................................................. ......9
System Description ...................................................9
POWER CONSUMPTION CONTROL SYS-
TEM ....................................................................
10
System Diagram .................................................. ....10
System Description .................................................10
Component Parts Location ......................................11
DIAGNOSIS SYSTEM (IPDM E/R) .....................12
Diagnosis Description ......................................... ....12
CONSULT - III Function (IPDM E/R) .......................14
COMPONENT DIAGNOSIS .........................17
U1000 CAN COMM CIRCUIT ...........................17
Description ........................................................... ....17
DTC Logic ................................................................17
Diagnosis Procedure ...............................................17
POWER SUPPLY AND GROUND CIRCUIT ....18
Diagnosis Procedure ...............................................18
ECU DIAGNOSIS .........................................19
IPDM E/R (INTELLIGENT POWER DISTRI-
BUTION MODULE ENGINE ROOM) ................
19
Reference Value .................................................. ....19
Terminal Layout .......................................................21
Physical Values ................................................... ....21
Wiring Diagram ........................................................26
Fail Safe ..................................................................29
DTC Index ...............................................................31
PRECAUTION ..............................................32
PRECAUTIONS .................................................32
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ....
32
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ...................................
32
REMOVAL AND INSTALLATION ...............34
IPDM E/R (INTELLIGENT POWER DISTRI-
BUTION MODULE ENGINE ROOM) ................
34
Removal and Installation of IPDM E/R ................ ....34
Revision: December 20092009 QX56