2011 INFINITI QX56 sensor

EC-44
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
VVEL SYSTEM : System Diagram
INFOID:0000000006217709
VVEL SYSTEM : System DescriptionINFOID:0000000006217710
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
JSBIA0539GB
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor
Crankshaft position sensor Engine speed and piston position
VVEL controlVVEL control module
↓
VVEL actuator motor assem-
bly
Accelerator pedal position sensor Accelerator pedal position
VVEL control shaft
position sensor
↓
VVEL control module Control shaft actual angle
1. VVEL control shaft position
sensor 2. Drive shaft 3. Link A
4. Eccentric cam 5. Output cam 6. Valve lifter
7. Intake valve 8. Intake camshaft sprocket 9. Control shaft
10. Ball screw shaft 11. Ball screw nu t 12. VVEL actuator motor assembly
13. Rocker arm 14. Link B
JSBIA0463ZZ
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-48
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
AUTOMATIC SPEED CONTROL DEVI CE (ASCD) : System Diagram
INFOID:0000000006217715
AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System DescriptionINFOID:0000000006217716
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM via the CAN communication line
BASIC ASCD SYSTEM
 Automatic Speed Control Device (ASCD) allows a dr iver to keep vehicle at predetermined constant speed
without depressing accelerator pedal. Driver can be set the vehicle speed in the set speed range.
 ECM controls throttle angle of electric th rottle control actuator to regulate engine speed.
 Operation status of ASCD is indicated in combination meter.
 If any malfunction occurs in the ASCD system, it automatically deactivates the ASCD control.
Refer to EC-49, "
AUTMATIC SPEED CONTROL DEVICE (A SCD) : Switch Name and Function" for ASCD
operating instructions.
CAUTION:
Always drive vehicle in a safe manner according to traffic conditions and obey all traffic laws.
CAN COMMUNICATION
CAN COMMUNICATION : System DescriptionINFOID:0000000006217718
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication s peed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CA N communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
Refer to LAN-28, "
CAN COMMUNICATION SYSTEM : CAN Communication Signal Chart", about CAN com-
munication for detail.
JPBIA3272GB
Sensor Input signal to ECM ECM function Actuator
ASCD steering switch ASCD steering switch operation
ASCD vehicle speed control Electric throttle control ac-
tuator
 Combination meter
ASCD brake switch
Brake pedal operation
Sto p l am p s w it ch
TCM Park/neutral position signal
Output shaft revolution signal*
Combination meter Vehicle speed signal*
Revision: 2010 May2011 QX56

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-51
< SYSTEM DESCRIPTION > [VK56VD]
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
Diagnosis DescriptionINFOID:0000000006217720
This system is an on board diagnostic system that re
cords exhaust emission-related diagnostic information
and detects a sensors/actuator-related malfunction. A ma lfunction is indicated by the malfunction indicator
lamp (MIL) and stored in ECU memory as a DTC. The diagnostic information can be obtained with the diag-
nostic tool (GST: Generic Scan Tool).
GST (Generic Scan Tool)INFOID:0000000006217721
When GST is connected with a data link connector equipped on the vehicle side, it will communicate with the
control unit equipped in the vehicle and then enable va rious kinds of diagnostic tests. Refer to GI-48, "
Descrip-
tion".
NOTE:
Service $0A is not applied for r egions where it is not mandated.
Revision: 2010 May2011 QX56

EC-60
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
DIAGNOSIS DESCRIPTION : Malf unction Indicator Lamp (MIL)
INFOID:0000000006217727
DESCRIPTION
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON with-
out the engine running. This is a bulb check.
If the MIL does not light up, refer to EC-515, "
Component Func-
tion Check".
2. When the engine is started, the MIL should go off. If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
On Board Diagn osis FunctionINFOID:0000000006217728
ON BOARD DIAGNOSIS ITEM
The on board diagnostic system has the following functions.
BLUB CHECK MODE
Description
This function allows damage inspection in the MIL bulb (blown, open circuit, etc.).
Operation Procedure
1. Turn ignition switch ON.
2. The MIL on the instrument panel should stay ON.
If it remains OFF, check MIL circuit. Refer to EC-515, "
Diagnosis Procedure".
SRT STATUS MODE
Description
This function allows to read if ECM has completed t he self-diagnoses of major emission control systems and
components. For SRT, refer to EC-58, "
DIAGNOSIS DESCRIPTION : Syst em Readiness Test (SRT) Code".
Operation Procedure
1. Turn ignition switch ON and wait 20 seconds.
2. SRT status is indicated as shown blow.
 ECM continues to illuminate MIL if all SRT codes are set.
SEF217U
Diagnostic test mode Function
Bulb check MIL can be checked.
SRT status ECM can read if SRT codes are set.
Malfunction warning If ECM detects a malfunction, it illuminates or blinks MIL to inform the driver that a malfunction has been detected.
Self-diagnostic results DTCs or 1st trip DTCs stored in ECM can be read.
Accelerator pedal released po-
sition learning ECM can learn the accelerator pedal released position. Refer to
EC-146, "
Description".
Throttle valve closed position
learning ECM can learn the throttle valve closed position. Refer to
EC-147, "
Description".
Idle air volume learning ECM can learn the idle air volume. Refer to EC-148, "
Description".
VVEL control sh aft position
sensor adjustment The initial position of the VVEL control shaft position sensor can be adjusted. Refer to
EC-150, "
De-
scription".
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-61
< SYSTEM DESCRIPTION > [VK56VD]
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 ECM blinks MIL for about 10 seconds if all SRT codes are not set.
MALFUNCTION WARNING MODE
Description
In this function ECM turns on or blinks MIL when it det
ects a malfunction in the emission control system com-
ponents and/or the powertrain control components (which affe ct vehicle emissions) to inform the driver that a
malfunction has been detected.
Operation Procedure
1. Turn ignition switch ON.
2. Check that MIL illuminates. If it remains OFF, check MIL circuit. Refer to EC-515, "
Diagnosis Procedure".
3. Start engine and let it idle.  For two trip detection logic diagnoses, ECM turns on MIL when it detects the same malfunction twice in
the two consecutive driving cycles.
 For 1st trip detection logic diagnoses, ECM turns on MIL when it detects a malfunction in one driving cycle.
 ECM blinks MIL when it detects a malfunction t hat may damage the three way catalyst (misfire).
SELF-DIAGNOSTIC RESULTS MODE
Description
This function allows to indicate DTCs or 1st trip DTCs stored in ECM according to the number of times MIL is
blinking.
How to Set Self-diagnostic Results Mode
NOTE:
 It is better to count the time accurately with a clock.
 It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a mal-
function.
 After ignition switch is turned off, ECM is a lways released from the “Self-diagnostic results” mode.
1. Confirm that accelerator pedal is fully releas ed, turn ignition switch ON and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.  Fully depress the accelerator pedal.
 Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it depressed for approx. 10 seconds until the
MIL starts blinking.
NOTE:
Do not release the accelerator pedal for 10 seconds if MIL starts blinking during this period. This blinking
is displaying SRT status and is continued for another 10 seconds.
4. Fully release the accelerator pedal. ECM has entered to Self-diagnostic results mode.
JMBIA1515GB
Revision: 2010 May2011 QX56

EC-64
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
*: This function is not necessary
in the usual service procedure.
SELF-DIAG RESULTS MODE
Self Diagnostic Item
Regarding items of DTC and 1st trip DTC, refer to EC-98, "DTC Index".
How to Read DTC and 1st Trip DTC
DTCs and 1st trip DTCs related to the malfunction are displayed in “Self-diag results”.
 When ECM detects a 1st trip DTC, “1t” is displayed for “TIME”.
 When ECM has detected a current DTC, “0” is displayed for “TIME”.
 If “TIME” is neither “0” nor “1t”, the DTC occurred in the past and ECM shows the number of times the vehi-
cle has been driven since the last detection of the DTC.
How to Erase DTC and 1st Trip DTC
NOTE:
 If the ignition switch stays ON after repair work, be su re to turn ignition switch OFF once. Wait at least 10
seconds and then turn it ON (engine stopped) again.
 If the DTC is not for A/T related items (see EC-98, "
DTC Index"), skip step 1.
1. Erase DTC in TCM. Refer to TM-60, "
Diagnosis Description".
2. Select “ENGINE” with CONSULT-III.
3. Select “SELF-DIAG RESULTS”.
4. Touch “ERASE”. (DTC in ECM will be erased.)
WORK ITEM CONDITION USAGE
IDLE AIR VOL LEARN  THE IDLE AIR VOLUME THAT KEEPS THE ENGINE
WITHIN THE SPECIFIED RANGE IS MEMORIZED IN
ECM. When learning the idle air volume
EVAP SYSTEM CLOSE CLOSE THE EVAP CANISTER VENT CONTROL VALVE IN
ORDER TO MAKE EVAP SYSTEM CLOSE UNDER THE
FOLLOWING CONDITIONS.
 IGN SW ON
 ENGINE NOT RUNNING
 AMBIENT TEMPERATURE IS ABOVE 0
°C (32 °F).
 NO VACUUM AND NO HIGH PRESSURE IN EVAP SYS-
TEM
 FUEL TANK TEMP. IS MORE THAN 0 °C (32 °F).
 WITHIN 10 MINUTES AFTER STARTING “EVAP SYS-
TEM CLOSE”
 WHEN TRYING TO EXECUTE “EVAP SYSTEM CLOSE” UNDER THE CONDITION EXCEPT ABOVE, CONSULT-
III WILL DISCONTINUE IT AND DISPLAY APPROPRI-
ATE INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-III MAY DIS-
PLAY “BATTERY VOLTAGE IS LOW. CHARGE BAT-
TERY”, EVEN WHEN USING A CHARGED BATTERY. When detecting EVAP vapor leak
in the EVAP system
FUEL PRESSURE RELEASE  FUEL PUMP WILL STOP BY TOUCHING “START” DUR-
ING IDLING.
CRANK A FEW TIMES AFTER ENGINE STALLS. When releasing fuel pressure from
fuel line
SELF-LEARNING CONT  THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL COEF-
FICIENT. When clearing mixture ratio self-
learning value
TARGET IDLE RPM ADJ*  IDLE CONDITION When setting target idle speed
VIN REGISTRATION  IN THIS MODE, VIN IS REGISTERED IN ECM. When registering VIN in ECM
TARGET IGN TIM ADJ*  IDLE CONDITION When adjusting target ignition tim-
ing
CLSD THL POS LEARN  IGNITION ON AND ENGINE STOPPED. When learning the throttle valve
closed position
VVEL POS SEN ADJ PREP  USE THIS ITEM ONLY WHEN REPLACING VVEL ACTU-
ATOR SUB ASSEMBLY.
 IGNITION ON AND ENGINE STOPPED. When adjusting VVEL control
shaft position sensor
Revision: 2010 May2011 QX56