2011 INFINITI QX56 Cooling

EC-32
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Refrigerant Pressure Sensor
INFOID:0000000006217690
The refrigerant pressure sensor is installed at the c ondenser of the air conditioner system. The sensor uses an
electrostatic volume pressure transducer to convert refrigerant pressure to voltage. The voltage signal is sent
to ECM, and ECM controls cooling fan system.
VVEL Actuator MotorINFOID:0000000006217691
The VVEL actuator motor rotates the control shaft acco rding to the control signal from the VVEL control mod-
ule. The VVEL control module judges whether the VVEL actuator motor controls the angle properly by the
VVEL control shaft position sensor signal.
VVEL Actuator Motor RelayINFOID:0000000006217692
Power supply for the VVEL actuator motor is provided to the VVEL control module via VVEL actuator motor
relay. VVEL actuator motor relay is ON/OFF controll ed by the VVEL control module. In addition, when the
VVEL actuator motor relay cannot be controlled by the VVEL control module for some reason, it ON/OFF con-
trolled by ECM.
VVEL Control ModuleINFOID:0000000006217693
The VVEL control module consists of a microcomputer and connec-
tors for signal input and output and for power supply. The VVEL con-
trol module controls VVEL system.
VVEL Control Shaft Position SensorINFOID:0000000006217694
VVEL control shaft position sensor detects the control shaft position
angle.
A magnet is installed to the tip of the control shaft.
The magnetic field changes as the control shaft rotates. This
changes output voltage of the VVEL control shaft position sensor.
VVEL control module detects the actual position angle through the
voltage change and sends the signal to ECM.
PBIB2657E
JMBIA0879ZZ
JSBIA0466ZZ
Revision: 2010 May2011 QX56

EC-36
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
DIRECT INJECTION GASOLINE SYSTEM
DIRECT INJECTION GASOLINE
SYSTEM : System DiagramINFOID:0000000006217699
DIRECT INJECTION GASOLINE SY STEM : System DescriptionINFOID:0000000006217700
INPUT/OUTPUT SIGNAL CHART
Function Reference
Fuel injection control EC-36, "
DIRECT INJECTION GASOLINE
SYSTEM : System De-
scription"
Fuel pressure control EC-39, "FUEL PRESSURE CONTROL : System Description"
Cooling fan controlEC-41, "COOLING FAN CONTROL : System Description"
Electric ignition controlEC-42, "ELECTRIC IGNITION SYSTEM : System Description"
Intake valve timing controlEC-43, "INTAKE VALVE TIMING CONTROL : System Description"
VVEL (Variable Valve Event & Lift) EC-44, "VVEL SYSTEM : System Description"
Evaporative emissionEC-45, "EVAPORATIVE EMISSION SYSTEM : System Descrip-
tion"
Air conditioning cut controlEC-47, "AIR CONDITIONING CUT CONT
ROL : System Descrip-
tion"
ASCD (Auto speed control device) EC-48, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : Sys-
tem Description"
Power generation voltage variable controlCHG-7, "POWER GENERATION VOLTAGE VARIABLE CON-
TROL SYSTEM : System Description"
JSBIA0471GB
Revision: 2010 May2011 QX56

EC-40
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
SYSTEM DESCRIPTION
Low fuel pressure control
 The low fuel pressure pump is controlled by the f
uel pump control module (FPCM) and pumps fuel according
to a driving condition. The pumped fuel passes through t he fuel filter and is sent to the high pressure fuel
pump. FPCM controls the low pressure fuel pump, ac cording to a signal from ECM as shown in the table
below.
 Low fuel pressure is adjusted by the fuel pressure regulator.
High fuel pressure control
 The high pressure fuel pump raises the pressure of the fuel sent from the low pressure fuel pump. Actuated
by the camshaft, the high pressure fuel pump activates the high pressure fuel pump solenoid based on a sig-
nal received from ECM, and adjusts the amount of di scharge by changing the timing of closing the inlet
check valve to control fuel rail pressure.
COOLING FAN CONTROL
JSBIA0235GB
Conditions Amount of fuel flow Supplied voltage
After a laps of 1 second after ignition ON OFF 0 V
 For 1 second after turning ignition switch ON
 Engine is running under low load and low speed conditions Low Approximately 8.5 V
 Engine cranking
 Engine coolant temperature is below 10 °C (50 °F)
 Engine is running under high load and high speed conditions High
Battery voltage
(11 – 14 V)
Except the above Mid Approximately 10 V
Revision: 2010 May2011 QX56

SYSTEMEC-41
< SYSTEM DESCRIPTION > [VK56VD]
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COOLING FAN CONTROL : System DiagramINFOID:0000000006217703
COOLING FAN CONTROL : System DescriptionINFOID:0000000006217704
INPUT/OUTPUT SIGNAL CHART
*1: The ECM determines the engine speed by the signals of crankshaft position and camshaft position.
*2: This signal is sent to ECM via the CAN communication line.
SYSTEM DESCRIPTION
 Based on a signal transmitted from each sensor, ECM calc
ulates a target fan speed responsive to a driving
condition. In addition, ECM calculates a fan pulley speed according to an engine speed and transmits a cool-
ing fan request signal to IPDM E/R via the CAN comm unication line to satisfy the target fan speed. Then,
IPDM E/R transmits ON/OFF pulse duty signal to electrically-controlled cooling fan coupling.
The cooling fan speed sensor detects a cooling f an speed and transmits the detection result to ECM.
 ECM judges the start signal state from the engine speed signal and battery voltage.
ELECTRIC IGNITION SYSTEM
JSBIA0237GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
1
Cooling fan speed request
signal*2
IPDM E/R
↓
Electrically-controlled cooling fan
coupling
Camshaft position sensor Camshaft position
Engine coolant temperature sensor Engine coolant temperature
Refrigerant pressure sensor Refrigerant pressure
Intake air temperature sensor Intake air temperature
Battery Battery voltage
Combination meter
Vehicle speed signal*
2
BCMA/C switch signal*2
Cooling fan speed sensor Cooling fan speed
Revision: 2010 May2011 QX56

EC-68
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
VEHICLE SPEED km/h or mph The vehicle speed computed from the vehicle
speed signal sent from TCM is displayed.
IDL A/V LEARN YET/CMPLT  Displays the condition of Idle Air Volume Learning
YET: Idle air volume learning has not been per-
formed yet.
CMPLT: Idle air volume learning has already been
performed successfully.
TRVL AFTER MIL km or mile  Distance traveled while MIL is activated.
SNOW MODE SW ON/OFF  Indicates [ON/OFF] condition from the snow mode
switch signal.
ENG OIL TEMP °C or °F  The engine oil temperature (determined by the sig-
nal voltage of the engine oil temperature sensor) is
displayed.
MAIN SW ON/OFF  Indicates [ON/OFF] condition from MAIN switch
signal.
CANCEL SW ON/OFF  Indicates [ON/OFF] condition from CANCEL
switch signal.
RESUME/ACC SW ON/OFF  Indicates [ON/OFF] condition from RESUME/AC-
CELERATE switch signal.
SET SW ON/OFF  Indicates [ON/OFF] condition from SET/COAST
switch signal.
BRAKE SW1 ON/OFF  Indicates [ON/OFF] condition from ASCD brake
switch signal.
BRAKE SW2 ON/OFF  Indicates [ON/OFF] condition of stop lamp switch
signal.
DIST SW ON/OFF  Indicates [ON/OFF] condition from DISTANCE
switch signal.
CRUISE LAMP ON/OFF  Indicates [ON/OFF] condition of CRUISE indicator
determined by the ECM according to the input sig-
nals.
AC EVA TEMP °C or °F  Indicates A/C evaporator temperature sent from A/
C auto amp.
AC EVA TARGET °C or °F  Indicates target A/C evaporator temperature sent
from A/C auto amp.
FAN DUTY %  Indicates a command value for cooling fan. The
value is calculated by ECM based on input signals.
ALT DUTY %  Indicates the duty ratio of the power generation
command value. The ratio is calculated by ECM
based on the battery current sensor signal.
BAT CUR SEN mV  The signal voltage of battery current sensor is dis-
played.
A/F ADJ-B1
— Indicates the correction of a factor stored in ECM.
The factor is calculated from the difference be-
tween the target air-fuel ratio stored in ECM and
the air-fuel ratio calculated from A/F sensor 1 sig-
nal.
A/F ADJ-B2
P/N POSI SW ON/OFF
 Indicates [ON/OFF] condition from the park/neutral
position (PNP) signal.
INT/A TEMP SE °C or °F  The intake air temperature (determined by the sig-
nal voltage of the intake air temperature sensor) is
indicated.
AC PRESS SEN V  The signal voltage from the refrigerant pressure
sensor is displayed.
FUEL PRES SEN MPa  Indicates the fuel rail pressure computed by ECM
according to the input signals
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-69
< SYSTEM DESCRIPTION > [VK56VD]
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FUEL INJ B1 msec
 ECM-calculated injection pulse width of the fuel in-
jector on the Bank 1 side.
FUEL INJ B2 msec  ECM-calculated injection pulse width of the fuel in-
jector on the Bank 2 side.
INT/V TIM (B1) °CA  Indicates [ °CA] of intake camshaft advance angle.
INT/V TIM (B2)
MAP SENSOR V  The signal voltage from the manifold absolute
pressure (MAP) sensor is displayed.
EVAP LEAK DIAG YET/CMPLT  Indicates the condition of EVAP leak diagnosis.
YET: EVAP leak diagnosis has not been performed
yet.
CMPLT: EVAP leak diagnosis has been performed
successfully.
EVAP DIAG READY ON/OFF  Indicates the ready condition of EVAP leak diagno-
sis.
ON: Diagnosis has been ready condition.
OFF: Diagnosis has not been ready condition.
VVEL LEARN YET/DONE  Display the conditi
on of VVEL learning
YET: VVEL learning has not been performed yet.
DONE: VVEL learning has already been per-
formed successfully.
VVEL SEN LEARN-B1 V  Indicates the VVEL learning value.
VVEL SEN LEARN-B2
VVEL POSITION SEN-B1 V The VVEL control shaft position sensor signal volt-
age is displayed.
VVEL POSITION SEN-B2
VVEL TIM-B1
deg  Indicates [deg] of VVEL control shaft angle.
VVEL TIM-B2
FPCM HI/MID/LOW/
OFF  The control condition of the fuel pump control mod-
ule (FPCM) (determined by ECM according to the
input signals) is indicated.
BAT TEMP SEN V  The signal voltage from the battery temperature
sensor is displayed.
COOLING FAN SPD rpm  Displays a cooling fan speed from a signal of elec-
trically-controlled cooling fan coupling.
THRTL STK CNT B1* — —
HO2 S2 DIAG2(B1)* INCMP/CM-
PLT  Indicates DTC P0139 self-diagnosis (slow re-
sponse) condition.
INCMP: Self-diagnosis is incomplete.
CMPLT: Self-diagnosis is complete.
HO2 S2 DIAG2(B2)* INCMP/CM-
PLT  Indicates DTC P0159 self-diagnosis (slow re-
sponse) condition.
INCMP: Self-diagnosis is incomplete.
CMPLT: Self-diagnosis is complete.
FUEL INJ TIMG deg  Indicates the fuel injection timing computed by
ECM according to the input signals.
H/P FUEL PUMP DEG deg  Displays ECM-calculated fuel discharge position
of the high pressure fuel pump.
FUEL PRES SEN V mV  The signal voltage of FRP sensor is displayed.
L/FUEL PRES SEN MPa  Displays a pressure value calculated from a low
fuel pressure sensor voltage.
L/FUEL PRES SEN V mV  The signal voltage of low fuel pressure sensor is
displayed.
Monitored item Unit Description Remarks
Revision: 2010 May2011 QX56

EC-70
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: The item is indicated, but not used.
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
ECM TEMP 1
°C or °F  Displays a temperature calculated from a signal of
ECM temperature sensor 1.
ECM TEMP 2 °C or °F  Displays a temperature calculated from a signal of
ECM temperature sensor 2.
FUEL PUMP DUTY %  The control condition of the fuel pump control mod-
ule (FPCM) (determined by ECM according to the
input signals) is indicated.
Monitored item Unit Description Remarks
TEST ITEM CONDITION JUDGMENT CHECK ITEM (REMEDY)
VENT CON-
TROL/V  Ignition switch: ON (Engine
stopped)
 Turn solenoid valve ON and OFF with the CONSULT-III and listen
to operating sound. Solenoid valve makes an operating
sound.
 Harness and connectors
 Solenoid valve
ENG COOLANT
TEMP  Engine: Return to the original
non-standard condition
 Change the engine coolant tem- perature using CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.  Harness and connectors
 Engine coolant temperature sen-
sor
 Fuel injector
FUEL INJEC-
TION  Engine: Return to the original
non-standard condition
 Change the amount of fuel injec- tion using CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.
 Harness and connectors
 Fuel injector
 Air fuel ratio (A/F) sensor 1
FUEL/T TEMP
SEN  Change the fuel tank temperature using CONSULT-III.
PURG VOL
CONT/V  Engine: After warming up, run en-
gine at 1,500 rpm.
 Change the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-III. Engine speed changes according to
the opening percent.
 Harness and connectors
 Solenoid valve
FAN DUTY CON-
TROL* Ignition switch: ON
 Change duty ratio using CON-
SULT-III. Cooling fan speed changes.  Harness and connectors
 Cooling fan motor
 Cooling fan relay
 Cooling fan control module
 IPDM E/R
ALTERNATOR
DUTY Engine: Idle
 Change duty ratio using CON-
SULT-III. Battery voltage changes.  Harness and connectors
 IPDM E/R
Alternator
POWER BAL-
ANCE  Engine: After warming up, idle the
engine.
 A/C switch OFF
 Selector lever: P or N
 Cut off each injector signal one at a time using CONSULT-III. Engine runs rough or stops.
 Harness and connectors
 Compression
 Fuel injector
 Power transistor
Spark plug
 Ignition coil
IGNITION TIM-
ING  Engine: Return to the original
non-standard condition
 Timing light: Set
 Retard the ignition timing using
CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.
 Perform Idle Air Volume Learning.
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-71
< SYSTEM DESCRIPTION > [VK56VD]
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For items whose SRT codes are set, “CMPLT” is disp
layed on the CONSULT-III screen; for items whose SRT
codes are not set, “INCMP” is displayed.
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
*: DTC P1456 does not apply but appears in DTC Work Support Mode screens. V/T ASSIGN AN-
GLE
 Engine: Return to the original
non-standard condition
 Change intake valve timing using CONSULT-III. If malfunctioning symptom disap-
pears, see CHECK ITEM.
 Harness and connectors
 Intake valve timing control sole-
noid valve
FPCM  Engine: Return to the original
trouble condition
 Select “LOW”, “MID” and “HI” with CONSULT-III. Fuel pump speed changes or stops.
 Harness and connectors
 Fuel pump control module (FPCM)
TEST ITEM CONDITION JUDGMENT CHECK ITEM (REMEDY)
Test mode Test item Corresponding DTC No. Reference page
HO2S2 HO2S2 (B1) P1146 P0138
EC-249
HO2S2 (B1) P1147 P0137EC-243
HO2S2 (B1) P0139 P0139EC-257
HO2S2 (B2) P1166 P0158EC-249
HO2S2 (B2) P1167 P0157EC-243
HO2S2 (B2) P0159 P0159EC-257
A/F SEN1A/F SEN1 (B1) P1278/P1279 P0133
EC-238A/F SEN1 (B1) P1276 P0130EC-228
A/F SEN1 (B2) P1288/P1289 P0153EC-238
A/F SEN1 (B2) P1286 P0150EC-228
EVAPORATIVE SYSTEMEVP V/S LEAK P0456/P1456* P0456
EC-346, "
DTC Logic"
PURG VOL CN/V P1444 P0443EC-317, "DTC Logic"
PURG FLOW P0441 P0441EC-312, "DTC Logic"
Revision: 2010 May2011 QX56