low oil pressure INFINITI QX56 2009 Factory Service Manual

BCS
DIAGNOSIS SYSTEM (BCM)BCS-27
< FUNCTION DIAGNOSIS > [BCM]
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AIR PRESSURE MONITOR
AIR PRESSURE MONITOR : Diagnosis DescriptionINFOID:0000000003776404
DESCRIPTION
During driving, the TPMS receives the signal transmitt
ed from the transmitter installed in each wheel, when
the tire pressure becomes low. The control unit (BC M) of this system has pressure judgment and trouble diag-
nosis functions.
When the TPMS detects low inflation pressure or anot her unusual symptom, the warning lamps in the combi-
nation meter comes on.
SELF DIAGNOSTIC PROCE DURE (WITH CONSULT-III)
With CONSULT-III
 Touch “SELF-DIAG RESULTS” display to show malf unction experienced since the last erasing operation.
Refer to BCS-51, "DTC Index"
.
SELF DIAGNOSTIC PROCE DURE (WITHOUT CONSULT-III)
Without CONSULT-III
To start the self-diagnostic results mode, ground terminal of the tire pressure warning check connector. The
malfunction location is indicated by the warning lamp flashing.
NOTE:
When the low tire warning lamp flashes 5 Hz and continues repeating it, the system is normal.
Test Item Operation Description
OIL PRESSURE SW OFF OFF
ON
BCM transmits the oil pressure switch signal to the combination meter via CAN communica-
tion, which operates the oil pressure gauge in the combination meter.
SEIA0745E
Flickering
pattern Items Diagnostic items detected when··· Check item
15 Tire pressure value (Front LH) Front LH tire pressure drops to 181 kPa (1.8 kg/cm, 25.25 psi) or less.
–
16 Tire pressure value (Front RH) Front RH tire pressure drops to 181 kPa (1.8 kg/cm, 25.25 psi) or less.
17 Tire pressure value (Rear RH) Rear RH tire pressure drops to 181 kPa (1.8 kg/cm, 25.25 psi) or less.
18 Tire pressure value (Rear LH) Rear LH tire pressure drops to 181 kPa (1.8 kg/cm, 25.25 psi) or less.
21 Transmitter no data (Front LH) Data from front LH transmitter can not be received.
WT-27
22 Transmitter no data (Front RH) Data from front RH transmitter can not be received.
23 Transmitter no data (Rear RH) Data from Rear RH transmitter can not be received.
24 Transmitter no data (Rear LH) Data from Rear LH transmitter can not be received.
Revision: December 20092009 QX56

CCS
INSPECTION AND ADJUSTMENTCCS-5
< BASIC INSPECTION >
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INSPECTION AND ADJUSTMENT
ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT
ADDITIONAL SERVICE WHEN REPL ACING CONTROL UNIT : Description
INFOID:0000000003776923
Always perform the laser beam aiming adjustment after repl acing the ICC unit. In addition, test the ICC sys-
tem operations to see if it functions normally.
ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT : Special Repair Re-
quirement
INFOID:0000000003776924
1.LASER BEAM AIMING ADJUSTMENT
Adjust laser beam aiming. Refer to CCS-5, "
LASER BEAM AIMING ADJUSTMENT : Outline of Laser Beam
Aiming Adjustment Procedure".
>> GO TO 2
2.ICC SYSTEM ACTION TEST
1. Perform the ICC system operation test. Refer to CCS-8, "
ACTION TEST : ICC System Running Test".
2. Check that the ICC system operates normally.
>> INSPECTION END.
LASER BEAM AIMI NG ADJUSTMENT
LASER BEAM AIMING ADJUSTMENT : Outlin e of Laser Beam Aiming Adjustment
Procedure
INFOID:0000000003776925
CAUTION:
• The laser beam aiming adjustment can not be performed without CONSULT-III.
• The laser beam aiming adjustment must be performed every time the ICC sensor is removed,
installed or has been moved as a result of a collision.
1. Prepare the vehicle and the work area.
2. Set up the ICC target board. For details, refer to Technical Service Bulletin.
3. Adjust the sensor following the procedure on CONSULT-III.
4. Check system operation after the adjustment.
LASER BEAM AIMING ADJU STMENT : PreparationINFOID:0000000003776926
• Place the vehicle on level ground. Shift the transmi ssion into "P" position and release the parking brake.
• Adjust the tire pressure to the specified value.
• See that there is no load in the vehicle. Coolant , engine oil and fuel should be filled to correct level.
• Check that the vehicle suspension has been adjusted to the standard height by the load leveling rear air sus-
pension system. Refer to SCS-7, "
CONSULT-III Function" .
• Clean the sensor with a soft cloth. Tool number : KV99110100 (J-45718)
LKIA0632E
Revision: December 20092009 QX56

ENGINE COOLANTCO-11
< ON-VEHICLE MAINTENANCE >
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Inspect the radiator cap.
NOTE:
Thoroughly wipe out the radiator filler
neck to remove any waxy resi-
due or foreign material.
• Replace the cap if the metal plunger cannot be seen around the edge of the black rubber gasket.
• Replace the cap if deposits of waxy residue or other foreign mate- rial are on the black rubber gasket or the metal retainer.
• Pull negative-pressure valve to open it and make sure that it closes completely when released.
• Make sure that there is no dirt or damage on the valve seat of radi-
ator cap negative-pressure valve.
• Make sure that there are no unusualness in the opening and clos- ing conditions of negative-pressure valve.
Changing Engine CoolantINFOID:0000000003771285
WARNING:
• To avoid being scalded, never change the coolant when the engine is hot.
• Wrap a thick cloth around the cap to carefully remo ve the cap. First, turn the cap a quarter of a turn
to release any built-up pressure, then push down and turn the cap all the way to remove it.
DRAINING ENGINE COOLANT
1. Turn ignition switch ON and set temperature control lever all the way to HOT position or the highest tem-
perature position. Wait 10 seconds and turn ignition switch OFF.
2. Remove the engine front undercover using power tool.
3. Open the radiator drain plug at the bottom of the radiator, and remove the radiator filler cap. This is the only step required
when partially draining the cooling system (radiator only).
CAUTION:
Do not to allow the coolant to contact the drive belts.
4. When draining all of the coolant in the system for engine removal or repair, it is necessary to drain the cylinder block.
Remove the RH cylinder block drain plug to drain the right bank
and the oil cooler hose to drain the left bank as shown.
PBIC2816E
SMA967B
WBIA0391E
PBIC0146E
Revision: December 20092009 QX56

DLN-10
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
FUNCTION DIAGNOSIS
4WD SYSTEM
System DiagramINFOID:0000000003772075
COMPONENT DESCRIPTION
WDIA0164E
Components Function
Transfer control unit Controls transfer control device, control valves and shifts between 2WD/4WD and 4H/4LO.
Transfer control device Integrates actuator motor and actuator position switch.
2-4WD shift solenoid valve Controls oil pressure and allows shifting between 2WD and 4WD.
Clutch pressure solenoid valve Controls oil pressure and distributes torque between front and rear tires.
Line pressure switch Detects line pressure.
Clutch pressure switch Detects clutch pressure.
Transfer fluid temperature sensor Detects transfer fluid temperature.
Actuator motor Moves shift rods when signaled by transfer control unit.
Actuator position switch Detects actuator motor position.
Wait detection switch Detects whether or not 4WD lock gear is locked.
4LO switch Detects if transfer case is in 4LO.
ATP switch Detects if transfer case is in neutral.
4WD shift switch Allows driver to select from 2WD/4WD, 4H/4LO and AUTO.
4WD warning lamp • Illuminates if malfunction is detected in 4WD system.
 Flashes (1 flash / 2 seconds) if large difference in diameter of front and rear tires.
 Flashes (2 flashes / 1 second) if high transfer fluid temperature is detected.
AT P w a r n i n g l a m p Indicates that A/T parking mechanism does not operate when A/T selector lever is in P position
because transfer case is in neutral.
4WD shift indicator lamp Displays driving range selected by 4WD shift switch.
4LO indicator lamp Displays 4LO range.
Revision: December 20092009 QX56

DLN-14
< FUNCTION DIAGNOSIS >[ATX14B]
4WD SYSTEM
 Displays 4LO condition while engine is running. 4LO indi
cator lamp flashes if transfer gear does not shift
completely under 2WD, AUTO, 4H ⇔4LO. (When 4WD warning lamp is turned on, 4LO indicator lamp is
turned off.)
 Turns ON for approximately 1 second when ignition switch is turned ON, for purpose of lamp check.
4WD WARNING LAMP
Turns on or flashes when there is a malfunction in 4WD system.
Also turns on when ignition switch is turned ON, for purpose of lamp che\
ck. Turns OFF approximately 1 sec-
ond after the engine starts if system is normal.
4WD Warning Lamp Indication
ATP WARNING LAMP
When the A/T selector lever is in P position, the vehicle may move if the transfer case is in neutral. ATP warn-
ing lamp is turned on to indicate this condition to the driver.
LINE PRESSURE SWITCH
 With the transfer system design, cont rol of the oil pressure provides the transmission of drive torque to the
front wheels. The main pressure to control the oil pressure is referred to as the line pressure.
 The line pressure switch determines whether or not adequate line pressure has built up under different oper-
ating conditions.
 The line pressure switch closes when line pressure is produced.
 The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.
CLUTCH PRESSURE SWITCH
 The clutch pressure switch determines whether or not adequate clutch pressure has built up under different
operating conditions.
 The clutch pressure switch closes when clutch pressure is produced.
 The clutch pressure switch senses clutch pressu re abnormalities and turns the 4WD warning lamp ON.
WAIT DETECTION SWITCH
 The wait detection switch operates when there is circulating torque produced in the propeller shaft (L→H) or
when there is a phase difference between 2-4 sleeve and clutch drum (H →L). After the release of the circu-
lating torque, the wait detection switch helps provi de the 4WD lock gear (clutch drum) shifts. A difference
may occur between the operation of the 4WD shift swit ch and actual drive mode. At this point, the wait
detection switch senses an actual drive mode.
 The wait detection switch operates as follows.
- 4WD lock gear (clutch drum) locked: ON
- 4WD lock gear (clutch drum) released: OFF
 The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the vehi-
cle drive mode.
ATP SWITCH
ATP switch detects if transfer case is in neutral by the position of the L-H shift fork.
NOTE:
Transfer case may be in neutral when shifting between 4H-4LO.
NEUTRAL-4LO SWITCH
The neutral-4LO switch detects that tr ansfer gear is in neutral or 4LO (or shifting from neutral to 4LO) condi-
tion by L-H shift fork position.
Condition 4WD warning lamp
System normal OFF
Lamp check Turns ON when ignition switch is turned ON.
Turns OFF after engine start.
4WD system malfunction ON
During self-diagnosis Flashes malfunction mode.
Large difference in diameter of front/
rear tires Flashes slow (1 flash / 2 seconds)
(Continues to flash until the ignition switch is turned OFF)
High fluid temperature in transfer case Flashes rapidly (2 flashes / 1 second)
(Continues to flash until fluid temperature returns to normal)
Revision: December 20092009 QX56

4WD SYSTEMDLN-15
< FUNCTION DIAGNOSIS > [ATX14B]
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TRANSFER FLUID TEMPERATURE SENSOR
The transfer fluid temperature sensor detects the trans fer fluid temperature and sends a signal to the transfer
control unit.
TRANSFER MOTOR
 The transfer motor drives the sub-oil pump to provi de proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.
 The main oil pump is operated by the driving force of t he mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standsti ll 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 vehi cle operations, the transfer motor drives the sub-oil
pump to compensate for insufficient oil pressure.
 The transfer motor operates as follows:
- The motor relay turns OFF in the 2WD mode.
- The motor relay operates as described in the table below in modes other than the 2WD mode.
 4WD shift switch, transmission range switch, Neutral-4LO switch, vehicle speed sensor and throttle position
sensor are used in conjunction with the transfer motor.
Transfer Motor Relay Operation
*: After 2.5 seconds have elapsed.
CLUTCH PRESSURE SOLENOID VALVE
The clutch pressure solenoid valve distributes front and rear torque in AUTO 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 trans mitted to the front wheels through the clutch so 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.
TRANSFER CONTROL DEVICE
Integrates actuator motor and actuator position switch.
4WD shift switch A/T selector lever position Vehicle speed
(VSS) Accelerator pedal position Motor relay drive
command
2WD — — — OFF
4H (LOCK) and 4LO N position 0 — ON
P position 0
0 - 0.07/8 OFF*
0.07/8 - 1/8 HOLD 1/8 - MAX ON
Other than R position 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
R position — — ON
R position — — ON
AUTO P or N position 0
0 - 0.07/8 OFF*
0.07/8 - 1/8 HOLD 1/8 - MAX ON
0 < VSS ≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
Other than R, P and N posi-
tion 0 < VSS
≤ 50 km/h (31 MPH)
— ON
50 km/h (31 MPH) < VSS < 55 km/h (34 MPH) HOLD
55 km/h (34 MPH) ≤ VSS OFF
Revision: December 20092009 QX56

4WD SYSTEMDLN-17
< FUNCTION DIAGNOSIS > [ATX14B]
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CAN CommunicationINFOID:0000000003772078
Refer to LAN-51, "DTC Index".
1. A: Transfer shut off relay E69
B: Transfer shift low relay E47
C: Transfer shift high relay E46 2. A: Actuator
B: Transfer control device F58
C: Actuator lever
D: Transfer case 3. Wait detection switch F59
(View with transfer case removed)
4. A: Clutch pressure switch B: Line pressure switch
C: Transfer fluid temperature sensor
D: 2-4WD shift solenoid valve
E: Clutch pressure solenoid valve
(View with contro l valve removed
from transfer case) 5. A: Neutral 4LO switch F60
B: ATP switch F55
C: Transfer motor F57
D: Transfer terminal cord assembly F56
E: Oil filter 6. Combination meter M23, M24
A: 4WD warning lamp
B: ATP warning lamp
C: 4LO indicator lamp (located in in-
formation display)
D: 4WD shift indicator lamp
7. 4WD shift switch M141 8. Transfer control unit E142, E143 9. A: Transfer dropping resistor E135 B: Transfer motor relay E153, E154
(View with battery removed)
Revision: December 20092009 QX56

TRANSFER CONTROL UNITDLN-99
< ECU DIAGNOSIS > [ATX14B]
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CAUTION:
 If CAN COMM CIRCUIT [U1000] or CONTROL UNIT (CAN) [U1010] is displayed with other DTCs, first perform the trouble
diagnosis for CAN communication line.
 If ABS OP SIG [P1830], VDC OP SIG [P1831] or TCS OP SIG [P1832] is displayed, first perform the trouble diagnosis for ABS system.
 If VHCL SPEED SEN·AT [P1807] is displayed, firs t perform the trouble diagnosis for A/T system.
NOTE:
 If SHIFT ACT POSI SW [P1818] or SHIFT ACT CIR [P1819] is disp layed, first erase self-diagnostic results. (SHIFT ACT POSI SW
[P1818] or SHIFT ACT CIR [P1819] may be displayed after installing transfer control unit or transfer assembly.)
 If CL PRES SW [P1827] or LINE PRES SW [P1828] is displayed only while driving in reverse, check the continuity of R position o n
transmission range switch. When there is no malfunction found in the electrical system, check the hydraulic system.
FLASH CODE CHART
[P1826] OIL TEMP SEN Signal voltage from transfer fluid temperature sen-
sor is abnormally high (Transfer fluid temperature is
abnormally low) while driving. Refer to
DLN-67.
[P1827] CLUTCH PRES SW  Improper signal from clutch pressure switch is in-
put due to open or short circuit.
 Malfunction occurs in clutch pressure switch or
hydraulic circuit. Refer to
DLN-70
.
[P1828] LINE PRES SW  Improper signal from line pressure switch is input
due to open or short circuit.
 Malfunction occurs in line pressure switch or hy-
draulic circuit. Refer to
DLN-73
.
[P1829] THROTTLE POSI SEN  Malfunction is detected in accelerator pedal posi-
tion signal that is output from ECM through CAN
communication.
 Signal voltage from accelerator pedal position sensor is abnormally high or low. Refer to
DLN-76
.
[P1830] ABS OP SIG Malfunction is detected in ABS operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication. Refer to
DLN-77
.
[P1831] VDC OP SIG Malfunction is detected in VDC operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication.
Refer to
DLN-78
.
[P1832] TCS OP SIG Malfunction is detected in TCS operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication. Refer to
DLN-79
.
[U1010] CONTROL UNIT (CAN) Detecting error during the initial diagnosis of CAN
controller of transfer control unit. Refer to
DLN-80
DTC CONSULT-III Diagnostic item is detected when... Reference
Flashing pattern Item Diagnostic item is detected when... Reference
2 Vehicle speed signal
(from A/T)  Malfunction is detected in output shaft revolution signal
that is output from TCM through CAN communication.
 Improper signal is input while driving. Refer to
DLN-26
.
3 Clutch pressure sole-
noid signal Proper voltage is not applied to clutch pressure solenoid
valve due to open or short circuit.
Refer to
DLN-53
.
4 2-4WD solenoid signal Proper voltage is not applied to 2-4WD solenoid valve due
to open or short circuit.
Refer to
DLN-57
.
5 Transfer motor Transfer motor does not operate properly due to open or
short circuit in transfer motor or transfer motor relay. Refer to
DLN-61
.
6 Vehicle speed signal
(from ABS)  Malfunction is detected in vehicle speed signal that is out-
put from ABS actuator and elec tric unit (control unit)
through CAN communication.
 Improper signal is input while driving. Refer to
DLN-27
.
7 CAN communication Malfunction has been detected from CAN communication
line. Refer to
LAN-51
.
Revision: December 20092009 QX56

EC-22
< FUNCTION DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM
Engine Control Comp onent Parts Location
INFOID:0000000003771302
1. ECM 2. Battery current sensor 3. Power steering pressure sensor
4. Ignition coil (with power transistor)
and spark plug (bank 2) 5. Refrigerant pressure sensor 6. Intake valve timing control position
sensor (bank 2)
7. Intake valve timing control solenoid valve (bank 2) 8. Engine coolant temperature sensor 9. Electric throttle control actuator
10. Intake valve timing control position sensor (bank 1) 11. Intake valve timing control solenoid
valve (bank 1) 12. Cooling fan motor
13. Camshaft position sensor (PHASE) 14. I gnition coil (with power transistor)
and spark plug (bank 1) 15. Mass air flow sensor (with intake air
temperature sensor)
16. A/F sensor 1 (bank 1) 17. EVAP service port 18. Fuel injector (bank 1)
19. Knock sensor (bank 1) 20. EVAP canister purge volume control solenoid valve21. Knock sensor (bank 2)
22. Fuel injector (bank 2) 23. A/F sensor 1 (bank 2) 24. IPDM E/R
BBIA0743E
Revision: December 20092009 QX56

TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-77
< COMPONENT DIAGNOSIS > [VK56DE]
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Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
ely 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK >> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> GO TO 5.
NG >> GO TO 6.
5.CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil. NOTE:
This symptom may occur when a large amount of gas oline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detect ed after changing engine oil or changing driving con-
dition.
>>INSPECTION END
6.CHECK FUEL PRESSURE
Check fuel pressure. (Refer to EC-487, "Fuel Pressure Check"
.)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-487, "Fuel Pressure Check"
.
GO TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7.DETECT MALFUNCTIONING PART
1. Check the following.
- Clogged and bent fuel hose and fuel tube
- Clogged fuel filter
- Fuel pump and its circuit (Refer to EC-487, "Fuel Pressure Check"
.)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-487, "Fuel Pressure Check"
.)
If OK, replace fuel pressure regulator.
Revision: December 20092009 QX56