2004 INFINITI QX56 Electric

ALL-MODE 4WD SYSTEM
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Description of Electrical PartsEDS0017R
TRANSFER MOTOR
1. The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.
2. The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle
is being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump
does not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the
sub-oil pump to compensate for insufficient oil pressure.
3. The transfer motor operates as follows:
1. The motor relay turns OFF in the 2WD mode.
2. The motor relay operates as described in the table below in modes other than the 2WD mode.
Ta b l e 1
Ta b l e 2
NOTE:
OFF (after 2.5 seconds have elapsed.)
4. 4WD shift switch, PNP switch, Neutral-4LO switch, vehicle speed sensor and throttle position sensor are
used in conjunction with the transfer motor.
WAIT DETECTION SWITCH
1. The wait detection switch releases the “booming” torque produced in the propeller shaft. After the release
of the “booming” torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts. A
difference may occur between the operation (“4LO” to “4H” shift only) of the 4WD shift switch and actual
drive mode. At this point, the wait detection switch senses an actual drive mode.
2. The wait detection switch operates as follows:
4WD lock gear (clutch drum) locked: ON
4WD lock gear (clutch drum) released: OFF
3. The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the
vehicle drive mode.
2-4WD SHIFT SOLENOID VALVE
The 2-4WD shift solenoid valve operates to apply oil pressure to the wet, multiplate clutch, depending on the
drive mode. The driving force is transmitted to the front wheels through the clutch when the vehicle is set in the
4WD mode. Setting the vehicle in the 2WD mode requires no pressure buildup. In other words, pressure force
applied to the wet, multiplate clutch becomes zero.
PNP switch “R” position VFF (Vehicle speed) A/T position Motor relay drive command
ON — R ON
OFF0Positions other than the “P” or
“N” positionsON
—“P” or “N” position (See Table
2.)—
0 < VFF ≤ 50 km/h (31 MPH) — ON
50 km/h (31 MPH) < VFF < 55
km/h (34 MPH)—HOLD
55 km/h (34 MPH) ≤ VFF — OFF
A/T position N-4L SW 4WD modeThrottle position
0 - 0.07/8 0.07/8 - 1/8 1/8 - MAX
NOFFLOCK (4H) ON ON ON
Positions other than
the LOCK position
(2WD or AUTO)See NOTE. HOLD ON
ON — See NOTE. HOLD ON
P——See NOTE.HOLDON

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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Note 1: When a malfunction occurs, it is only displayed and not stored in the memory.
Note 2: When the wait detection switch has been properly fixed, malfunction information is erased from the memory.
Note 3: If 4WD shift switch is left between 4H and 4LO for a while, this indication may be displayed.
(*1): If the malfunction is detected only while driving in reverse, check the continuity of “R” position on A/T PNP switch. When there is
nothing wrong with the electrical system, check the hydraulic system.
(*2): If a revolution sensor malfunction is detected at the same time, check the revolution sensor circuit first.
Note 4: When this malfunction is detected with the ABS warning lamp off, first check for disconnection or shorting in the harness
between the transfer control unit and the ABS control unit.
Note 5: When several systems including CAN communication system indicate malfunctions, perform diagnosis of the CAN communica-
tion first.Shift actuator abnormal
(SHIFT ACT)Transfer control device actuator motor is malfunctioning.
(Malfunctions are detected when actuator motor fails to
operate while shifting from “4H” to “4LO” or vice versa.) Refer to TF-77, "
Diagnostic Proce-
dure" or TF-82, "Diagnostic Pro-
cedure" .
Shift actuator position switch
abnormal
(SHIFT ACT P/S)Transfer control device actuator motor arm position sens-
ing switch is malfunctioning.Refer to TF-80, "
Diagnostic Proce-
dure" or TF-82, "Diagnostic Pro-
cedure" .
Shift actuator circuit abnormal
(SHIFT ACT CIR)Transfer control device actuator circuit is shorted or open.
(Malfunctions are detected when motor relay circuit is
open/shorted or relay monitor circuit is open/shorted.)Refer to TF-77, "
Diagnostic Proce-
dure" , TF-80, "Diagnostic Proce-
dure"TF-82, "Diagnostic
Procedure" .
Memory power supply stop

Due to removal of battery which cuts off power supply to
transfer control unit, self-diagnosis memory function is
suspended.Refer to TF-76, "Diagnostic Proce-
dure" .
Transfer control unit (RAM)
[CONTROL UNIT (RAM)]

Malfunction is detected in the memory (RAM) system of
transfer control unit.—
Transfer control unit (ROM)
[CONTROL UNIT (ROM)]

Malfunction is detected in the memory (ROM) system of
transfer control unit.—
Transfer control unit (EEPROM)
[CONTROL UNIT (EEPROM)]

Malfunction is detected in the memory (EEPROM) sys-
tem of transfer control unit.—
Longitudinal G-sensor Displayed, but do not use. —
ABS VHL SPD SEN

ABS vehicle speed sensor signal is not input due to an
open circuit.

An unexpected signal is input when vehicle is being
driven.Refer to ABS vehicle speed sensor
diagnosis.
STEERING ANGLE SENSOR Displayed, but do not use. —
VDC OPER SIGIf VDC operation signal is being input because of VDC
malfunction or communication error within the vehicle.Refer to BRC-40, "
ABS/TCS/VDC
Control Unit Inspection" .
TCS OPER SIGIf TCS operation signal is being input because of TCS mal-
function or communication error within the vehicle.Refer to BRC-40, "
ABS/TCS/VDC
Control Unit Inspection" .
CAN COMM (Note 5) Malfunction is detected in CAN communication.Refer to LAN-5, "
CAN COMMUNI-
CATION" .
A/T POSITION SIGNALWhen AT PNP switch circuit is malfunction or communica-
tion error between the vehiclesRefer to AT-109, "
DTC P0705
PARK/NEUTRAL POSITION
SWITCH" . Detected items
(Screen terms for CONSULT-II,
“SELF-DIAG RESULT” mode)Malfunction is detected when... Check items

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TROUBLE DIAGNOSIS — INTRODUCTION
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TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionEDS0017W
DESCRIPTION
When a malfunction (indicated by the 4WD warning lamp illumination) occurs, collect information first from the
customer about how the malfunction occurs. Then, proceed with the diagnosis presuming it is the cause. Also
inspect the electrical system, paying close attention to other possibilities such as fluid level and leaks.
All-mode 4WD transfer is controlled by transfer control unit and sensors.
If a malfunction occurs in the all-mode 4WD system, the 4WD warning lamp lights up to inform of the system
malfunction. There are two ways to identify the cause of the malfunction.
1. Performing the self-diagnosis. (The 4WD warning lamp will indicate what kind of malfunction has occurred
by flickering.)
2. Performing diagnosis using CONSULT-II.
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS

WHAT ..... Vehicle model

WHEN..... Date, Frequencies

WHERE..... Road conditions

HOW..... Operating conditions, Symptoms
Diagnostic Worksheet
Information sheet from customer
Customer name MR/MS Model & Year VIN
Transfer model
AT X 1 4 BEngine Mileage
Incident Date Manuf. Date In Service Date
Frequency❏ Continuous ❏ Intermittent ( times a day)
Symptoms❏ 4WD shift indicator lamp does not turn on.
❏ 4WD warning lamp does not turn on.
❏ 4WD shift indicator lamp does not turn off.
❏ ATP warning lamp does not turn on.
❏ 4LO indicator lamp does not turn on.
❏ 4WD shift indicator lamp does not indicate “4H”.
❏ 4WD shift indicator lamp repeats flicking.
❏ Tight corner braking symptom occurs.
❏ 4WD system does not operate.
❏ Others.
4WD warning lamp❏ Continuously lit❏ Not lit
1.❏ Listen to customer complaints.TF-47
2.❏ Check transfer fluid.TF-47
❏ Leakage
❏ Fluid condition
❏ Fluid level
3.❏ Road testingTF-47
❏ 1. Check before engine is started.
❏ 2. Check at idle.
❏ 3. Cruise test
4.❏ Perform self-diagnosis NG items (with CONSULT-II and without CONSULT-II).TF-31
, TF-28

REMOVAL AND INSTALLATION
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REMOVAL AND INSTALLATIONPFP:00000
RemovalEDS0018V
1. Remove A/T undercover using power tools.
2. Remove center exhaust tube and muffler. Refer to EX-3, "
EXHAUST SYSTEM" .
3. Remove front and rear propeller shafts. Refer to PR-5, "
REMOVAL" (front) and PR-9, "REMOVAL"
(rear).
CAUTION:
Be careful not to damage spline, sleeve yoke and rear oil seal when removing the rear propeller
shaft
NOTE:
Insert a plug into rear oil seal after removing rear propeller shaft.
4. Remove A/T mount bolts. Refer to AT-255, "
TRANSMISSION ASSEMBLY" .
5. Position two suitable jacks under A/T and transfer assembly.
6. Remove crossmember. Refer to TF-109, "
REMOVAL AND INSTALLATION" .
WAR NIN G:
Support A/T and transfer assembly using two suitable jacks while removing crossmember.
7. Disconnect the ATP switch, neutral 4LO switch, wait detection switch, transfer motor and transfer control
device electrical connectors.
8. Remove breather hoses from the actuator, transfer rear case and transfer motor.
9. Remove the shift actuator from the extension housing.
10. Remove transfer to A/T bolts.
WAR NIN G:
Support transfer assembly with suitable jack while removing it.
11. Remove transfer assembly.
InstallationEDS0018W
1. Installation is in the reverse order of removal.
Bolt length : 45 mm (1.77 in)
Transfer bolt torque : 36 N·m (3.7 kg-m, 26 ft-lb)
SMT872C

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TROUBLE DIAGNOSES
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CONSULT-II Function (BCM)EES001PT
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
BCM
diagnostic test itemDiagnostic mode Description
Inspection by partWORK SUPPORTSupports inspections and adjustments. Commands are transmit-
ted to the BCM for setting the status suitable for required opera-
tion, input/output signals are received from the BCM and received
data is displayed.
DATA MONITOR Displays BCM input/output data in real time.
ACTIVE TESTOperation of electrical loads can be checked by sending drive sig-
nal to them.
SELF-DIAG RESULTS Displays BCM self-diagnosis results.
CAN DIAG SUPPORT MNTRThe result of transmit/receive diagnosis of CAN communication
can be read.
ECU PART NUMBER BCM part number can be read.
CONFIGURATION Performs BCM configuration read/write functions.

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WIPER, WASHER & HORN
K ELECTRICAL
CONTENTS
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SECTION WW
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WW
Revision: August 20072004 QX56 PRECAUTION ............................................................ 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Wiring Diagrams and Trouble Diagnosis .................. 3
FRONT WIPER AND WASHER SYSTEM .................. 4
Components Parts and Harness Connector Loca-
tion ........................................................................... 4
System Description .................................................. 4
LOW SPEED WIPER OPERATION ...................... 5
HI SPEED WIPER OPERATION ........................... 5
INTERMITTENT OPERATION .............................. 5
AUTO STOP OPERATION .................................... 6
FRONT WASHER OPERATION ........................... 6
MIST OPERATION ................................................ 6
FAIL-SAFE FUNCTION ......................................... 6
COMBINATION SWITCH READING FUNCTION ..... 7
CAN Communication System Description ................ 7
Schematic ................................................................ 8
Wiring Diagram — WIPER — .................................. 9
Terminals and Reference Values for BCM ............. 12
Terminals and Reference Values for IPDM E/R ..... 13
Work Flow .............................................................. 13
Preliminary Inspection ............................................ 13
INSPECTION FOR POWER SUPPLY AND
GROUND CIRCUIT ............................................. 13
CONSULT-II Function (BCM) ................................. 15
CONSULT-II OPERATION .................................. 15
DATA MONITOR ................................................. 16
ACTIVE TEST ..................................................... 17
CONSULT-II Function (IPDM E/R) ......................... 17
CONSULT-II OPERATION .................................. 17
DATA MONITOR ................................................. 18
ACTIVE TEST ..................................................... 19
Trouble Diagnosis .................................................. 19
FRONT WIPER DOES NOT OPERATE ............. 19
FRONT WIPER STOP POSITION IS INCOR-
RECT .................................................................. 22
ONLY FRONT WIPER LOW DOES NOT OPER-
ATE ..................................................................... 23ONLY FRONT WIPER HI DOES NOT OPERATE ... 25
ONLY FRONT WIPER INT DOES NOT OPER-
ATE ...................................................................... 26
FRONT WIPER INTERMITTENT OPERATION
SWITCH POSITION CANNOT BE ADJUSTED ... 27
WIPERS DO NOT WIPE WHEN FRONT
WASHER OPERATES ........................................ 27
FRONT WIPERS OPERATE FOR 10 SECONDS,
STOP FOR 20 SECONDS, AND AFTER
REPEATING THIS OPERATION FIVE TIMES,
THEY BECOME INOPERATIVE ......................... 27
Removal and Installation of Front Wiper Arms,
Adjustment of Wiper Arms Stop Location ............... 29
REMOVAL ........................................................... 29
INSTALLATION ................................................... 29
Removal and Installation of Wiper Motor and Link-
age .......................................................................... 29
REMOVAL ........................................................... 29
INSTALLATION ................................................... 30
Washer Nozzle Adjustment .................................... 30
Washer Tube Layout .............................................. 31
Removal and Installation of Wiper and Washer
Switch ..................................................................... 31
REMOVAL ........................................................... 31
INSTALLATION ................................................... 31
Removal and Installation of Washer Tank .............. 31
REMOVAL ........................................................... 31
INSTALLATION ................................................... 32
Removal and Installation of Washer Motor ............. 32
REAR WIPER AND WASHER SYSTEM .................. 33
Components Parts and Harness Connector Loca-
tion .......................................................................... 33
System Description ................................................. 33
REAR WIPER OPERATION ................................ 33
INTERMITTENT OPERATION ............................ 34
AUTO STOP OPERATION .................................. 35
REAR WASHER OPERATION ............................ 35
BCM WIPER SWITCH READING FUNCTION .... 36
Wiring Diagram — WIP/R — .................................. 37
Terminals and Reference Values for BCM .............. 39

PRECAUTION
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PRECAUTION PFP:00011
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EKS007F3
The Supplemental Restraint System such as “AIR 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 whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WA RN ING:

To avoid rendering the SRS inoperative, 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Wiring Diagrams and Trouble Diagnosis EKS007F4
When you read wiring diagrams, refer to the following:

Refer to GI-15, "How to Read Wiring Diagrams" .

Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit.
When you perform trouble diagnosis, refer to the following:

Refer to GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES" .

Refer to GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident" .

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FRONT WIPER AND WASHER SYSTEM
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BCM detects ON/OFF status of intermittent wiper dial position

BCM calculates operation interval from wiper dial position and vehicle speed signal received through CAN
communications.

BCM sends front wiper request signal (INT) to IPDM E/R at calculated operation interval.
When the IPDM E/R receives a front wiper request signal (INT), it supplies ground to energize the front wiper
relay. It then sends an auto-stop signal to the BCM, and conducts intermittent front wiper motor operation.
AUTO STOP OPERATION
When the wiper arms are not located at the base of the windshield, and the wiper switch is turned OFF, the
wiper motor will continue to operate until the wiper arms reach the windshield base. When the wiper arms
reach the base of windshield, front wiper motor terminals 6 and 1 are connected.
Ground is supplied

to IPDM E/R terminal 43

through front wiper motor terminal 6

through front wiper motor terminal 1

through grounds E9, E15 and E24.
The IPDM E/R sends an auto stop operation signal to the BCM through CAN communication lines.
When the BCM receives an auto stop operation signal, the BCM sends wiper stop signal to the IPDM E/R over
CAN communication lines. The IPDM E/R then de-energizes the front wiper relay.
The wiper motor will then stop the wiper arms at the STOP position.
FRONT WASHER OPERATION
When the ignition switch is in the ON or START position, and the front and rear washer switches are OFF, the
front and rear washer motor is supplied power

through 10A fuse (No. 9, located in the fuse block J/B)

through combination switch (wiper switch) terminal 14

through combination switch (wiper switch) terminal 13

to front and rear washer motor terminal 1, and

through combination switch (wiper switch) terminal 11

to front and rear washer motor terminal 2.
When the front wiper switch is in the front washer position, the BCM detects a front washer signal request
through the combination switch (wiper switch) reading function.
Combination switch ground is supplied

to front and rear washer motor terminal 2

through combination switch (wiper switch) terminal 11

through combination switch (wiper switch) terminal 12

through grounds M57, M61 and M79.
With ground supplied, the front and rear washer motor is operated in the front direction.
When the BCM detects that front washer motor has operated for 0.4 seconds or longer, the BCM uses CAN
communication and sends a wiper request signal to the IPDM E/R for low speed operation of wipers.
When the BCM detects that the washer switch is OFF, low speed operation cycles approximately 3 times and
then stops.
MIST OPERATION
When the wiper switch is temporarily placed in the mist position, wiper low speed operation cycles once and
then stops. For additional information about wiper operation under this condition, refer to WW-5, "
LOW
SPEED WIPER OPERATION" .
If the switch is held in the mist position, low speed operation continues.
FAIL -S AFE F UN CTI ON
The BCM includes fail-safe function to prevent malfunction of electrical components controlled by CAN com-
munications if a malfunction in CAN communications occurs.
The BCM uses CAN communications to stop output of electrical components it controls.
Until the ignition switch is turned off, the front wiper system remains in same status as just before fail-safe con-
trol was initiated. (If wiper was in low speed operation just before fail-safe, it continues low speed operation
until ignition switch is turned OFF.)
When fail-safe status is initiated, the BCM remains in standby until normal signals are received.