engine coolant INFINITI QX56 2011 Factory Owner's Guide

SYSTEMEC-39
< SYSTEM DESCRIPTION > [VK56VD]
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Fuel is injected into each cylinder during each engine cycle accord-
ing to the ignition order.
STRATIFIED-CHARGE START CONTROL
The use of the stratified-charge combustion met
hod enables emissions-reduction when starting the engine
with engine coolant temperature between 5 °C (41 °F) and 40 °C (104 °F).
FUEL SHUT-OFF
Fuel to each cylinder is shut-off during deceleration, operation of the engine at excessively high speed or oper-
ation of the vehicle at excessively high speed.
FUEL PRESSURE CONTROL
FUEL PRESSURE CONTROL : System DiagramINFOID:0000000006217701
FUEL PRESSURE CONTROL : System DescriptionINFOID:0000000006217702
INPUT/OUTPUT SIGNAL CHART
JSBIA0407GB
JSBIA0315GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed
Fuel injection
& mixture ratio
controlHigh pressure fuel pump
Camshaft position sensor Camshaft position
Fuel rail pressure sensor Fuel rail pressure
Low fuel pressure sensor Low fuel pressure
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage
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-42
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
ELECTRIC IGNITION SYSTEM : System Diagram
INFOID:0000000006217705
ELECTRIC IGNITION SYSTEM : System DescriptionINFOID:0000000006217706
INPUT/OUTPUT SIGNAL CHART
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
Ignition order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Comput-
ing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is re vised by the ECM according to the other data stored in
the ECM.
 At starting
 During warm-up
 At idle
 At low battery voltage
 During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
JPBIA3271GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
1
Piston position
Ignition timing
controlIgnition coil
(with power transistor)
Camshaft position sensor
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
TCM Gear position
Battery
Battery voltage*
1
Knock sensor Engine knocking condition
Combination meterVehicle speed*
2
Revision: 2010 May2011 QX56

SYSTEMEC-43
< SYSTEM DESCRIPTION > [VK56VD]
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INTAKE VALVE TIMING CONTROL
INTAKE VALVE TIMING CONTROL : System DiagramINFOID:0000000006217707
INTAKE VALVE TIMING CONT
ROL : System DescriptionINFOID:0000000006217708
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
This mechanism hydraulically controls cam phases c ontinuously with the fixed operating angle of the intake
valve.
The ECM receives signals such as crankshaft posit ion, camshaft position, engine speed, and engine coolant
temperature. Then, the ECM sends ON/OFF pulse duty signals to the intake valve timing control solenoid
valve depending on driving status. This makes it possible to control the shut/open timing of the intake valve to
increase engine torque in low/mid speed range and output in high speed range.
VVEL SYSTEM
JMBIA2174GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed and piston position
Intake valve timing
controlIntake valve timing control
solenoid valve
Camshaft position sensor
Engine oil temperature sensor Engine oil temperature
Engine coolant temperature sensor Engine coolant temperature
Combination meter Vehicle speed*
PBIB3276E
Revision: 2010 May2011 QX56

EC-46
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
The evaporative emission system is used to reduce hydr
ocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplis hed by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into t he EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not oper ating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume contro l solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve also shuts off the vapor purge line during decelerating and
idling.
AIR CONDITIONING CUT CONTROL
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor
Camshaft position sensor  Engine speed*
1
 Piston position
EVAP canister
purge flow controlEVAP canister purge volume
control solenoid valve
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Battery
Battery voltage*
1
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
(Mixture ratio
feedback signal)
Fuel tank temperature sensor Fuel temperature in fuel tank
EVAP control system pressure sensor Pressure in purge line
Combination meter Vehicle speed*
2
PBIB1631E
Revision: 2010 May2011 QX56

SYSTEMEC-47
< SYSTEM DESCRIPTION > [VK56VD]
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AIR CONDITIONING CUT CONTROL : System DiagramINFOID:0000000006217713
AIR CONDITIONING CUT CONTROL : System DescriptionINFOID:0000000006217714
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned OFF.
 When the accelerator pedal is fully depressed.
 When cranking the engine.
 At high engine speeds.
 When the engine coolant temperature becomes excessively high.
 When operating power steering during low engine speed or low vehicle speed.
 When engine speed is excessively low.
 When refrigerant pressure is excessively low or high.
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
JMBIA1457GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor
Camshaft position sensor Engine speed*
2
Air conditioner cut
controlIPDM E/R
↓
A/C relay
↓
Compressor
Engine coolant temperature sensor Engine coolant temperature
Accelerator pedal position sensor Accelerator pedal position
Battery
Battery voltage*
2
Refrigerant pressure sensor Refrigerant pressure
Power steering pressure sensor Power steering operation
A/C auto amp.A/C ON signal*
1
A/C evaporator temperature*1
Target A/C evaporator temperature*1
Blower fan ON signal
Combination meter Vehicle speed*
1
Revision: 2010 May2011 QX56

EC-50
< SYSTEM DESCRIPTION >[VK56VD]
OPERATION
- Engine coolant temperature is slightly higher than
the normal operating temperature. Then CRUISE indica-
tor lamp is blinked slowly.
NOTE:
Engine coolant temperature decreases to the norma l operating temperature, CRUISE indicator lamp stop
blinking and the cruise operation is able to work.
- Malfunction for some self-diagnoses regarding ASCD s ystem. CRUISE indicator lamp is blinked quickly.
 When ASCD MAIN switch is turned to OFF during the cr uise control driving, all of ASCD operations is can-
celed and vehicle speed memory is erased.
Revision: 2010 May2011 QX56

EC-52
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS DESCRIPTION
DIAGNOSIS DESCRIPTION : 1st Trip Detect
ion Logic and Two Trip Detection Logic
INFOID:0000000006217722
When a malfunction is detected for the first time, 1st tr ip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MIL will not illuminate at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MIL illuminates. The MIL illu minates at the same time when the DTC is stored.
<2nd trip> The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is per-
formed during vehicle operation. Specific on board diagnos tic items will cause the ECM to illuminate or blink
the MIL, and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
×: Applicable —: Not applicable
DIAGNOSIS DESCRIPTION : DT C and Freeze Frame DataINFOID:0000000006217723
DTC AND 1ST TRIP DTC
The 1st trip DTC (whose number is the same as the DT C number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously , and the 1st trip DTC did not recur, the 1st trip DTC
will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is saved in the ECM memory. The MIL will not
light up (two trip detection logic). If the same malfunc tion is not detected in the 2nd trip (meeting the required
driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same malfunction is detected in the
2nd trip, both the 1st trip DTC and DTC are saved in the ECM memory and the MIL lights up. In other words,
the DTC is stored in the ECM memory and the MIL light s up when the same malfunction occurs in two consec-
utive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed between the 1st and 2nd
trips, only the 1st trip DTC will continue to be stored. Fo r malfunctions that blink or light up the MIL during the
1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
For malfunctions in which 1st trip DTCs are displayed, refer to EC-98, "
DTC Index". These items are required
by legal regulations to continuous ly monitor the system/component. In addi tion, the items monitored non-con-
tinuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979/ ISO 15031-5. 1st trip DTC detection occurs without illu-
minating the MIL and therefore does not warn the driver of a malfunction.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in Work Flow procedure Step 2, refer to EC-135, "
Work Flow". Then perform DTC Confirma-
tion Procedure or Component Function Check to try to duplicate the malfunction. If the malfunction is dupli-
cated, the item requires repair.
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are ca lled freeze frame data and displayed on CONSULT-III or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-III screen.
Items MIL DTC 1st trip DTC
1st trip 2nd trip 1st trip
displaying 2nd trip
displaying 1st trip
displaying 2nd trip
displaying
Blinking Illuminate Blinking Illuminate
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected ×
——— — — ×—
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected ——
×—— ×——
One trip detection diagnoses (Re-
fer to EC-98, "
DTC Index".) —
×—— ×———
Except above — — — ×— ×× —
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-55
< SYSTEM DESCRIPTION > [VK56VD]
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 The B counter will be cleared when the malfunction is
detected once regardless of the driving pattern.
 The B counter will be counted up when driving pattern B is satisfied without any malfunction.
 The MIL will turn OFF when the B counter reaches 3. (*2 in “OBD SYSTEM OPERATION CHART”)

Driving pattern C means operating vehicle as per the following:
The following conditions should be satisfied at the same time:
Engine speed: (Engine speed in the freeze frame data) ±375 rpm
Calculated load value: (Calculated load value in the freeze frame data) x (1 ±0.1) [%]
Engine coolant temperature (T) condition:
 When the freeze frame data shows lower than 70 °C (158 °F), T should be lower than 70 °C (158 °F).
 When the freeze frame data shows higher than or equal to 70 °C (158 °F), T should be higher than or equal to
70 °C (158 °F).
Example:
If the stored freeze frame data is as per the following:
Engine speed: 850 rpm, Calculated load val ue: 30%, Engine coolant temperature: 80°C (176 °F)
To be satisfied with driving pattern C, the v ehicle should run under the following conditions:
Engine speed: 475 - 1,225 rpm, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70°C
(158 °F)
 The C counter will be cleared when the malfunction is detected regardless of vehicle conditions above.
 The C counter will be counted up when vehicle conditions above are satisfied without the same malfunction.
 The DTC will not be displayed after C counter reaches 80.
 The 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC is
stored in ECM.
Relationship Between MIL, DTC, 1st Trip DTC and Driving Patterns Except For “Misfire Quality Deterioration>”, “Fuel Injection System”
Revision: 2010 May2011 QX56