2011 INFINITI QX56 check engine

EC-14
< PREPARATION >[VK56VD]
PREPARATION
PREPARATION
PREPARATION
Special Service ToolsINFOID:0000000006217654
Commercial Service ToolsINFOID:0000000006217655
Tool number
(Kent-Moore No.)
Tool nameDescription
KV10118400
(—)
Fuel tube adapter Measures fuel pressure
PBIB3043E
Tool name
(Kent-Moore No.)
Description
Leak detector
i.e.: (J-41416) Locates the EVAP leak
EVAP service port adapter
i.e.: (J-41413-OBD) Applys positive pressure through EVAP service
port
Fuel filler cap adapter
i.e.: (MLR-8382) Checks fuel tank vacuum relief valve opening
pressure
Socket wrench Removes and installs engine coolant temperature sensor
S-NT703
S-NT704
S-NT815
S-NT705
Revision: 2010 May2011 QX56

EC-30
< SYSTEM DESCRIPTION >[VK56VD]
COMPONENT PARTS
Knock Sensor
INFOID:0000000006217683
The knock sensor is attached to t he cylinder block. It senses engine
knocking using a piezoelectric element. A knocking vibration from
the cylinder block is sensed as vibrational pressure. This pressure is
converted into a voltage signal and sent to the ECM.
Low Fuel Pressure SensorINFOID:0000000006217684
The low fuel pressure sensor is installed to low fuel pressure piping
and measures the low fuel pressu re. The sensor transmits voltage
signal to the ECM. As the pressure increases, the voltage rises.
Low Pressure Fuel PumpINFOID:0000000006217685
The low pressure fuel pump is integrated with a fuel pressure regula-
tor and a fuel filter. This pump is build into the fuel tank.
ECM controls the low pressure fuel pump via FPCM.
Malfunction Indicator Lamp (MIL)INFOID:0000000006217686
The Malfunction Indicator Lamp (MIL) is located on the combination
meter.
The MIL will illuminate when the ignition switch is turned ON without
the engine running. This is a bulb check.
When the engine is started, the MIL should turn off. If the MIL
remains illuminated, the on board diagnostic system has detected an
engine system malfunction.
For details, refer to EC-51, "
Diagnosis Description".
JSBIA0284ZZ
JSBIA0292ZZ
JPBIA3235ZZ
SEF217U
Revision: 2010 May2011 QX56

EC-34
< SYSTEM DESCRIPTION >[VK56VD]
STRUCTURE AND OPERATION
On Board Refueling V apor Recovery (ORVR)
INFOID:0000000006217696
From the beginning of refueling, the air and vapor insi de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:
 Put a “CAUTION: FLAMMABLE” sign in workshop.
 Never smoke while servicing fuel system. Keep open flames and sparks away from work area.
 Always furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
 Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-pr oof container and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-153, "
Work Procedure".
- Disconnect battery ground cable.
 Always replace O-ring when the fuel gauge retainer is removed.
 Never kink or twist hose and tube when they are installed.
 Never tighten hose and clamps excessively to avoid damaging hoses.
 After installation, run engine an d check for fuel leaks at connections.
 Never attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fu el overflow, resulting in fuel spray and possibly a fire.
PBIB1068E
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

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

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]
C
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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-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