2011 INFINITI QX56 change time

DLN-20
< SYSTEM DESCRIPTION >[TRANSFER: ATX90A]
SYSTEM
4WD Warning Lamp
 Turns ON when there is a malfunction in 4WD system. 4W
D warning lamp indicates the vehicle is in fail-safe
mode.
 Also turns ON when ignition switch is turned ON, fo r the purpose of lamp check. Turns OFF approximately
for 1 second after the engine starts if system is normal.
ATP Warning Lamp
When the A/T shift selector is in P position, the vehicle may move if the transfer case in neutral. ATP warning
lamp is turned on to indicate this condition to the driver.
CONDITION FOR OPERATE WARNING BUZZER
For preventing an incorrect operation during 4H ⇔4L switching, warning buzzer sounds from inside of transfer
control unit and warns the driver, when certain conditions are satisfied.
4WD SYSTEM : Fail-SafeINFOID:0000000006303692
 If any malfunction occurs in 4WD electrical system, and control unit detects the malfunction, 4WD warning
lamp on combination meter turns ON to indicate system malfunction.
 When 4WD warning lamp is ON, vehicle changes to rear-wheel drive or shifts to 4-wheel drive (front-wheels
still have some driving torque).
Condition 4WD warning lamp
Lamp check Turns ON when ignition switch is turned ON. Turns OFF ap-
prox. 1 second after the engine start.
4WD system malfunction ON
Protection function is activated due to heavy load to transfer assem-
bly. (4WD system is not malfunctioning.) Quick blinking: 2 times/second
(Blinking in approx. 1 minute and then turning OFF)
Large difference in diameter of front/rear tires Slow blinking: 1 time/2 seconds
(Continuing to blink until turning ignition switch OFF)
Other than above (system normal) OFF
Condition Warning buzzer
4WD shift status A/T shift selector Engine speed
4H⇔4L N range 350
− 1.600 rpm OFF
Under 350 rpm or over 1.600 rpm ON
Except N range Always
Revision: 2010 May2011 QX56

DLN-220
< UNIT DISASSEMBLY AND ASSEMBLY >[REAR FINAL DRIVE: R230]
DRIVE PINION
10. Apply anti-corrosion oil to the thread and seat of drive pinion
lock nut, and temporarily tighten drive pinion lock nut to drive
pinion, using flange wrench (c ommercial service tool).
CAUTION:
Never reuse drive pinion lock nut.
11. Adjust to the drive pinion lock nut tightening torque and pinion bearing preload torque, using preload gauge [SST: ST3127S000
(J-25765-A)].
CAUTION:
 Adjust to the lower limit of the drive pinion lock nut tight-
ening torque first.
 If the preload torque exceeds the specified value, replace
collapsible spacer and tighte n it again to adjust. Never
loosen drive pinion lock nut to adjust the preload torque.
 After adjustment, rotate dri ve pinion back and forth 2 to 3
times to check for unusual no ise, rotation malfunction,
and other malfunctions.
12. Install differential case assembly. Refer to DLN-206, "
Assem-
bly".
CAUTION:
Never install rear cover at this timing.
13. Check and adjust drive gear runout, tooth contact, drive gear to drive pinion backlash, and companion flange runout. Refer to DLN-210, "
Adjustment" and DLN-220, "Adjustment".
Recheck above items. Readjust the above description, if necessary.
14. Check total preload torque. Refer to DLN-210, "
Adjustment".
15. Install rear cover. Refer to DLN-206, "
Assembly".
AdjustmentINFOID:0000000006222428
COMPANION FLANGE RUNOUT
1. Fit a test indicator to the inner side of the companion flange
(socket diameter).
2. Rotate companion flange to check for runout.
3. If the runout value is outside t he runout limit, follow the proce-
dure below to adjust.
a. Check for runout while changing the phase between companion flange and drive pinion by 90 ° step, and search for the position
where the runout is the minimum.
b. If the runout value is still outside of the limit after the phase has been changed, possible cause will be an
assembly malfunction of drive pinion and pinion bearing and malfunction of pinion bearing. Check for
these items and repair if necessary.
c. If the runout value is still outside of the limit after the check and repair, replace companion flange.
InspectionINFOID:0000000006222429
INSPECTION AFTER DISASSEMBLY
Drive Gear and Drive Pinion
 Clean up the disassembled parts.
 If the gear teeth never mesh or line-up correctly, det ermine the cause and adjust or replace as necessary.
Pinion bearing preload : Refer to
DLN-222, "
Pre-
load Torque".
JSDIA0047ZZ
Inner side of companion
flange runout: Refer to
DLN-222, "Com-
panion Flange Runout".
JPDID0399ZZ
Revision: 2010 May2011 QX56

SYSTEMEC-37
< SYSTEM DESCRIPTION > [VK56VD]
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*1: This sensor is not used to control the engine system under normal conditions.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The adoption of the direct fuel injection method enables
more accurate adjustment of fuel injection quantity by
injecting atomized high-pressure fuel directly into the cylinder. This method allows high-powered engine, low
fuel consumption, and emissions-reduction.
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engi ne operating conditions. These conditions are determined
by input signals (for engine speed and intake air and fuel rail pressure) from the crankshaft position sensor,
camshaft position sensor, mass air flow sensor and the fuel rail pressure sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compens ated to improve engine performance under various operat-
ing conditions as listed below.
 During warm-up
 When starting the engine
 During acceleration
 Hot-engine operation
 When selector lever position is changed from N to D
 High-load, high-speed operation

 During deceleration
 During high engine speed operation
FUEL INJECTION CONTROL
Stratified-charge Combustion
Stratified-charge combustion is a combustion method wh ich enables extremely lean combustion by injecting
fuel in the latter half of a compression process, coll ecting combustible air-fuel around the spark plug, and form-
ing fuel-free airspace around the mixture.
Right after a start with the engine cold, the catalyst warm-up is accelerated by stratified-charge combustion.
Homogeneous Combustion
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor Engine speed*
2
Fuel injection
& mixture ratio
controlFuel injector
Camshaft position sensor Camshaft position
Mass air flow sensor Amount of intake air
Intake air temperature sensor Intake air temperature
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Fuel rail pressure sensor Fuel rail pressure
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
TCM Gear position
Battery
Battery voltage*
2
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit) VDC/TCS operation command
A/C auto amp. A/C ON signal
Combination meter Vehicle speed
Revision: 2010 May2011 QX56

EC-38
< SYSTEM DESCRIPTION >[VK56VD]
SYSTEM
Homogeneous combustion is a combustion method that fuel
is injected during intake process so that combus-
tion occurs in the entire combustion chamber , as is common with conventional methods.
As for a start except for starts with the engine cold, homogeneous combustion occurs.
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can better reduce CO , HC and NOx emissions. This system uses A/F sen-
sor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-21, "
Air Fuel Ratio (A/F) Sensor 1". This maintains the mixture ratio within the range of stoichiometric
(ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
 Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
- Deceleration and acceleration
- High-load, high-speed operation
- Malfunction of A/F sensor 1 or its circuit
- Insufficient activation of A/F sensor 1 at low engine coolant temperature
- High engine coolant temperature
- During warm-up
- After shifting from N to D
- When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors t he mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM c ontrols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass ai r flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value co mpared against the basic injection duration. Fuel trim
includes “short-term fuel trim” and “long-term fuel trim”.
“Short term fuel trim” is the short-term fuel compensati on used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long-term fuel trim” is overall fuel compensation carri ed out over time to compensate for continual deviation
of the “short-term fuel trim” from the central value. Continual deviation will occur due to individual engine differ-
ences, wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Sequential Direct Injection Gasoline System
PBIB2793E
Revision: 2010 May2011 QX56

OPERATIONEC-49
< SYSTEM DESCRIPTION > [VK56VD]
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OPERATION
AUTMATIC SPEED CONTROL DEVICE (ASCD)
AUTMATIC SPEED CONTROL DEVICE (A
SCD) : Switch Name and Function
INFOID:0000000006217719
SWITCHES AND INDICATORS
SET SPEED RANGE
ASCD system can be set the following vehicle speed.
SWITCH OPERATION
CANCEL CONDITION
 When any of following conditions exist, the cruise operation is canceled.
- CANCEL switch is pressed
- ASCD MAIN switch pressed (Set speed is cleared)
- More than two switches at ASCD steering switch ar e pressed at the same time (Set speed is cleared)
- Brake pedal is depressed
- Selector lever position is changed to N, P or R
- Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed
- TCS system is operated
 When the ECM detects any of the following conditions , the ECM cancels the cruise operation and informs
the driver by blinking CRUISE indicator lamp.
1. CRUISE indicator lamp 2. CANCEL switch 3. ASCD MAIN switch
4. SET/COAST switch 5. RESUME/ACCELERATE switch
A. On the combination meter B. On the steering wheel
JPBIA3226ZZ
Minimum speed (Approx.) Maximum speed (Approx.)
40 km/h (25 MPH) 143 km/h (88 MPH)
Item Function
CANCEL switch Cancels the cruise control driving.
RESUME/ACCELERATE switch  Resumes the set speed.
 Increases speed incrementally during cruise control driving.
SET/COAST switch  Sets desired cruise speed.
 Decreases speed incrementally during cruise control driving.
ASCD MAIN switch Master switch to activate the ASCD system.
(CRUISE indicator lamp is turn
ed ON when ASCD system is ON.)
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (ECM)EC-53
< SYSTEM DESCRIPTION > [VK56VD]
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Only one set of freeze frame data (either 1st trip freez
e frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM me mory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
For example, the EGR malfunction (Priority: 2) was detected and the freeze frame data was saved in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st tr ip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If fr eeze frame data is stored in the ECM memory and freeze
frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged in the
ECM memory.
Both 1st trip freeze frame data and freeze frame dat a (along with the DTCs) are cleared when the ECM mem-
ory is erased.
DIAGNOSIS DESCRIPTION : Counter SystemINFOID:0000000006217724
RELATIONSHIP BETWEEN MIL, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMS
 When a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
 When the same malfunction is detected in two consec utive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MIL will come on.
 The MIL will turn OFF after the vehicle is driven 3 ti mes (driving pattern B) with no malfunction. The drive is
counted only when the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs
while counting, the counter will reset.
 The DTC and the freeze frame data will be stored until the v ehicle is driven 40 times (driving pattern A) with-
out the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel Injec-
tion System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driving pattern
C) without the same malfunction recurring. The “TIM E” in “SELF-DIAGNOSTIC RESULTS” mode of CON-
SULT-III will count the number of times the vehicle is driven.
 The 1st trip DTC is not displayed when the se lf-diagnosis results in OK for the 2nd trip.
COUNTER SYSTEM CHART
For details about patterns B and C under “Fuel Inject ion System” and “Misfire”, see “EXPLANATION FOR
DRIVING PATTERNS FOR “MISFIRE ”, “FUEL INJECTION SYS-
TEM”.
For details about patterns A and B under Other, see “EXPLANATION FOR DRIVING PATTERNS FOR “MIS-
FIRE ”, “FUEL INJECTION SYSTEM”.
 *1: Clear timing is at the moment OK is detected.
 *2: Clear timing is when the same malfunction is detected in the 2nd trip.
Relationship Between MIL, DTC, 1st Trip DTC and Dr iving Patterns for “Misfire terioration>”, “Fuel Injection System”
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items
3 1st trip freeze frame data
Items Fuel Injection System Misfire Other
MIL (turns OFF) 3 (pattern B) 3 (pattern B) 3 (pattern B)
DTC, Freeze Frame Data (no display) 80 (p attern C) 80 (pattern C) 40 (pattern A)
1st Trip DTC (clear) 1 (pattern C), *1 1 (pattern C), *1 1 (pattern B)
1st Trip Freeze Frame Data (clear) *1, *2 *1, *2 1 (pattern B)
Revision: 2010 May2011 QX56

EC-62
< SYSTEM DESCRIPTION >[VK56VD]
DIAGNOSIS SYSTEM (ECM)
NOTE:
Wait until the same DTC (or 1st trip DTC)
appears to completely confirm all DTCs.
How to Read Self-diagnostic Results
The DTC and 1st trip DTC are indicated by the number of blinks of the MIL as shown below.
The DTC and 1st trip DTC are displayed at the same time. If the MIL does not illuminate in diagnostic test
mode I (Malfunction warning), all displayed items are 1s t trip DTCs. If only one code is displayed when the MIL
illuminates in “malfunction warning” mode, it is a DTC; if two or more codes are displayed, they may be either
DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These unidentified codes can be identified by
using the CONSULT-III or GST. A DTC will be used as an example for how to read a code.
A particular trouble code can be identified by the number of four-digit numeral flashes per the following.
The length of time the 1,000th-digit numeral flashes on and off is 1.2 seconds consisting of an ON (0.6-sec-
onds) - OFF (0.6-seconds) cycle.
The 100th-digit numeral and lower digit numerals consis t of a 0.3-seconds ON and 0.3-seconds OFF cycle.
A change from one digit numeral to another occurs at an inte rval of 1.0-second OFF. In other words, the later
numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8-seconds OFF.
PBIB0092E
PBIB3005E
Number 0123456789ABCDEF
Flashes 10123456789111213141516
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