check engine INFINITI QX56 2009 Factory Service Manual
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![INFINITI QX56 2009 Factory Service Manual
EC-42
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Therefore, when electrical controlled throttle and part
of ECM related diagnoses are continuously detected as
NG for 5 trips, EC](/img/42/57031/w960_57031-1368.png "INFINITI QX56 2009 Factory Service Manual
EC-42
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Therefore, when electrical controlled throttle and part
of ECM related diagnoses are continuously detected as
NG for 5 trips, EC")
EC-42
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Therefore, when electrical controlled throttle and part
of ECM related diagnoses are continuously detected as
NG for 5 trips, ECM warns the driver that engine cont rol system malfunctions and MIL circuit is open by means
of operating fail-safe function.
The fail-safe function also operates when above diagnos es except MIL circuit are detected and demands the
driver to repair the malfunction.
Emission-related Diagnostic InformationINFOID:0000000003771315
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 previous ly, and the 1st trip DTC did not reoccur, the 1st trip
DTC will not be displayed.
If a malfunction is detected during the 1st trip, the 1st trip DTC is stored 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 stored in t he 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.
Procedures for clearing the DTC and the 1st trip DT C from the ECM memory are described in "HOW TO
ERASE EMISSION-RELATED DI AGNOSTIC INFORMATION".
For malfunctions in which 1st trip DTCs are displa yed, refer to "EMISSION-RELATED DIAGNOSTIC INFOR-
MATION ITEMS". These items are required by legal regulations to continuously monitor the system/compo-
nent. In addition, the items monitored non-cont inuously are also displayed on CONSULT-III.
1st trip DTC is specified in Service $07 of SAE J1979. 1st trip DTC detection occurs without lighting up the MIL
and therefore does not warn the driver of a malfunction. However, 1st trip DTC detection will not prevent the
vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
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-8, "Trouble Diagnosis Introduction"
. Then per-
form DTC Confirmation Procedure or Overall Function Che ck to try to duplicate the malfunction. If the mal-
function is duplicated, the item requires repair.
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
With CONSULT-III
With GST
CONSULT-III or GST (Generic Scan Tool ) Examples: P0340, P0850, P1148, etc.
These DTCs are prescribed by SAE J2012.
(CONSULT-III also displays the malfunctioning component or system.)
No Tools
The number of blinks of the MIL in the Diagnostic Test Mode II (Self-Diagnostic Results) indicates the DTC.
Example: 0340, 0850, 1148, etc.
These DTCs are controlled by NISSAN.
1st trip DTC No. is the same as DTC No.
Output of a DTC indicates a malfunct ion. However, GST or the Diagnostic Test Mode II do not indi-
cate whether the malfunction is still occurring or h as occurred in the past and has returned to nor-
mal. CONSULT-III can identify ma lfunction status as shown below. Therefore, using CONSULT-III (if
available) is recommended.
DTC or 1st trip DTC of a malfunction is display ed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-III.
Time data indicates how many times the vehicle was driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be [0].
If a 1st trip DTC is stored in t he ECM, the time data will be [1t].
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.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
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ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-43
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Data which are stored in the ECM memory, along with the
1st trip DTC, are called 1st trip freeze](/img/42/57031/w960_57031-1369.png "INFINITI QX56 2009 Factory Service Manual
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-43
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Data which are stored in the ECM memory, along with the
1st trip DTC, are called 1st trip freeze")
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-43
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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 displa yed on the CONSULT-III screen, not on the GST. For
details, see EC-63, "CONSULT-III Function (ENGINE)"
.
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 (P riority: 2) was detected and the freeze frame data was stored 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. Procedures for clearing the ECM me mory are described in "HOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATION".
SYSTEM READINESS TEST (SRT) CODE
System Readiness Test (SRT) code is specified in Service $01 of SAE J1979.
As part of an enhanced emissions test for Inspection & Ma intenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has comple ted self-diagnosis of major emission systems and com-
ponents. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspec tion due to one or more SRT items indicating “INCMP”, use
the information in this Service Manual to set the SRT to “CMPLT”.
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate “CMPLT” for each application syste m. Once set as “CMPLT”, the SRT status remains
“CMPLT” until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate “INCMP” for these items.
NOTE:
The SRT will also indicate “INCMP” if the self-diagnosis memory is erased for any reason or if the ECM mem-
ory power supply is interrupted for several hours.
If, during the state emissions inspection, the SRT indica tes “CMPLT” for all test items, the inspector will con-
tinue with the emissions test. However, if the SRT i ndicates “INCMP” for one or more of the SRT items the
vehicle is returned to the customer untested.
NOTE:
If MIL is ON during the state emissi ons inspection, the vehicle is also returned to the customer untested even
though the SRT indicates “CMPLT” for all test items. T herefore, it is important to check SRT (“CMPLT”) and
DTC (No DTCs) before the inspection.
SRT Item
The table below shows required self-diagnostic items to set the SRT to “CMPLT”.
Priority Items
1 Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
SRT item
(CONSULT-III indication) Performance
Priority* Required self-diagnostic items to set the SRT to “CMPLT”
Corresponding
DTC No.
CATALYST 2 Three way catalyst function P0420, P0430
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EC-48
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Sea level
Flat road
Ambient air temperature: 20 - 30
°C (68 - 86 °F)
Diagnosis is performed as quickly as possible und](/img/42/57031/w960_57031-1374.png "INFINITI QX56 2009 Factory Service Manual
EC-48
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Sea level
Flat road
Ambient air temperature: 20 - 30
°C (68 - 86 °F)
Diagnosis is performed as quickly as possible und")
EC-48
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Sea level
Flat road
Ambient air temperature: 20 - 30
°C (68 - 86 °F)
Diagnosis is performed as quickly as possible under normal conditions.
Under different conditions [For example: ambient air temperature other than 20 - 30 °C (68 - 86 °F)], diagno-
sis may also be performed.
Pattern 1:
The engine is started at the engine coolant temperature of −10 to 35 °C (14 to 95 °F)
(where the voltage between the ECM te rminal 73 and ground is 3.0 - 4.3V).
The engine must be operated at idle speed until the engine coolant temperature is greater than 70°C
(158 °F) (where the voltage between the ECM te rminal 73 and ground is lower than 1.4V).
The engine is started at the fuel tank temperature of warmer than 0 °C (32 °F) (where the voltage
between the ECM terminal 107 and ground is less than 4.1V).
Pattern 2:
When steady-state driving is performed again even afte r it is interrupted, each diagnosis can be conducted.
In this case, the time required for diagnosis may be extended.
Pattern 3:
Operate vehicle following the driving pattern shown in the figure.
Release the accelerator pedal during decelerating vehicle speed from 90 km/h (56 MPH) to 0 km/h (0 MPH).
Pattern 4:
The accelerator pedal must be held very steady during steady- state driving.
If the accelerator pedal is moved, the test must be conducted all
over again.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56
MPH), then release the accelerator pedal and keep it released for
more than 10 seconds. Depress the accelerator pedal until vehicle
speed is 90 km/h (56 MPH) again.
*2: Checking the vehicle speed with GST is advised.
Suggested Transmissi on Gear Position
Set the selector lever in the D position with the overdrive switch turned ON.
TEST VALUE AND TEST LIMIT
The following is the information specified in Service $06 of SAE J1979.
The test value is a parameter used to determine whether a system/circuit diagnostic test is OK or NG while
being monitored by the ECM during self-diagnosis. The test limit is a reference value which is specified as the
maximum or minimum value and is compared with the test value being monitored.
These data (test value and test limit) are specified by On Boad Monitor ID(OBDMID), Test ID (TID), Unit and
Scaling ID and can be displayed on the GST screen.
The items of the test value and test limit will be di splayed with GST screen which items are provided by the
ECM. (eg., if the bank 2 is not applied on this v ehicle, only the items of the bank 1 is displayed)
PBIB2244E
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1. If the ignition switch stays ON after repair work, be su
re to turn ignition switch OFF once.](/img/42/57031/w960_57031-1381.png "INFINITI QX56 2009 Factory Service Manual
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-55
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1. If the ignition switch stays ON after repair work, be su
re to turn ignition switch OFF once.")
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-55
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1. 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.
2. Perform TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
. (The DTC in TCM will be erased)
3. Select Service $04 with GST (Generic Scan Tool).
No Tools
NOTE:
If the DTC is not for AT related items (see EC-456, "DTC Index"
), skip step 2.
1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once.
Wait at least 10 seconds and then turn it ON (engine stopped) again.
2. Perform TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
. (The DTC in the TCM will be erased.)
3. Change the diagnostic test mode from Mode II to Mode I by depressing the accelerator pedal. Refer to
EC-55, "Malfunction Indicator Lamp (MIL)"
.
If the battery is disconnected, the emission-relate d diagnostic information will be lost within 24
hours.
The following data are cleared when the ECM memory is erased.
- Diagnostic trouble codes
- 1st trip diagnostic trouble codes
- Freeze frame data
- 1st trip freeze frame data
- System readiness test (SRT) codes
- Test values
Actual work procedures are explained using a DTC as an ex ample. Be careful so that not only the DTC, but all
of the data listed above, are cleared from the ECM memory during work procedures.
Malfunction Indicator Lamp (MIL)INFOID:0000000003771316
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 MWI-18
or see EC-41.
2. When the engine is start ed, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
ON BOARD DIAGNOSTIC SYSTEM FUNCTION
The on board diagnostic system has the following three functions.
SEF217U
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EC-56
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
When there is an open circuit on MIL circuit, the ECM c
annot warn the driver by lighting up MIL when there is
malfunction on eng](/img/42/57031/w960_57031-1382.png "INFINITI QX56 2009 Factory Service Manual
EC-56
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
When there is an open circuit on MIL circuit, the ECM c
annot warn the driver by lighting up MIL when there is
malfunction on eng")
EC-56
< FUNCTION DIAGNOSIS >[VK56DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
When there is an open circuit on MIL circuit, the ECM c
annot warn the driver by lighting up MIL when there is
malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected as
NG for 5 trips, ECM warns the driver that engine cont rol system malfunctions and MIL circuit is open by means
of operating fail-safe function.
The fail-safe function also operates when above diagnos es except MIL circuit are detected and demands the
driver to repair the malfunction.
MIL Flashing Without DTC
When any SRT codes are not set, MIL may fl ash without DTC. For the details, refer to EC-456, "DTC Index".
HOW TO SWITCH DIAGNOSTIC TEST MODE
NOTE:
It is better to count the ti me accurately with a clock.
It is impossible to switch the di agnostic mode when an accelerator pedal position sensor circuit has
a malfunction.
Always ECM returns to Diagnostic Test Mode I after ignition switch is turned OFF.
How to Set Diagnostic Test Mode II (Self-diagnostic Results)
1. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the MIL starts
blinking.
NOTE:
Do not release the accelerator pedal for 10 seconds if MIL may start blinking on the halfway of this
10 seconds. This blinking is displaying SRT status and is continued for another 10 seconds. For
the details, refer to EC-456, "DTC Index"
.
Diagnostic Test
ModeKEY and ENG.
Status Function Explanation of Function
Mode I Ignition switch in ON position
Engine stopped BULB CHECK This function checks the MIL bulb for damage (blown, open
circuit, etc.).
If the MIL does not come on, check MIL circuit.
Engine running MALFUNCTION WARNING This is a usual driving condition. When a malfunction is de-
tected twice in two consecutive driving cycles (two trip de-
tection logic), the MIL will light up to inform the driver that a
malfunction has been detected.
The following malfunctions will light up or blink the MIL in
the 1st trip.
Misfire (Possible three way catalyst damage)
One trip detection diagnoses
Mode II Ignition switch in ON position
Engine stopped SELF-DIAGNOSTIC
RESULTS
This function allows DTCs an
d 1st trip DTCs to be read.
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
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ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-71
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overh](/img/42/57031/w960_57031-1397.png "INFINITI QX56 2009 Factory Service Manual
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-71
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overh")
ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-71
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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 details, refer to
EC-456, "DTC Index".
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
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION Engine: Return to the original
trouble condition
Change the amount of fuel injec-
tion using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Fuel injector
Air fuel ratio (A/F) sensor 1
IGNITION TIM-
ING Engine: Return to the original
trouble condition
Timing light: Set
Retard the ignition timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Perform Idle Air Volume Learning.
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 dies.
Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
COOLING FAN* Ignition switch: ON
Turn the cooling fan HI and OFF
using CONSULT-III. Cooling fan moves and stops. Harness and connectors
Cooling fan motor
IPDM E/R
ENG COOLANT
TEMP Engine: Return to the original
trouble condition
Change the engine coolant tem- perature using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM. Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
FUEL PUMP RE-
LAY Ignition switch: ON
(Engine stopped)
Turn the fuel pump relay ON and OFF using CONSULT-III and lis-
ten to operating sound. Fuel pump relay makes the operat-
ing sound.
Harness and connectors
Fuel pump relay
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
FUEL/T TEMP
SEN Change the fuel tank temperature using CONSULT-III.
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
V/T ASSIGN AN-
GLE Engine: Return to the original
trouble condition
Change intake valve timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Intake valve timing control sole-
noid valve
ALTERNATOR
DUTY Engine: Idle
Change duty ratio using CON-
SULT-III. Battery voltage changes. Harness and connectors
IPDM E/R
Alternator
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EC-76
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DETAILED PROCEDURE
1.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Confirm that the testing conditions](/img/42/57031/w960_57031-1402.png "INFINITI QX56 2009 Factory Service Manual
EC-76
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DETAILED PROCEDURE
1.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Confirm that the testing conditions")
EC-76
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DETAILED PROCEDURE
1.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Confirm that the testing conditions are met. Refer to EC-74, "Testing Condition"
.
3. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
NOTE:
PBIB3214E
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Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-77
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Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
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TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-77
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Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximat
ely 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.
OK or NG
OK >> GO TO 17.
NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.
2.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 4.
NG (More than the SP value)>>GO TO 19.
3.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> GO TO 6.
NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.
4.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Stop the engine.
2. Disconnect PCV hose, and then plug it.
3. Start engine.
4. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> GO TO 5.
NG >> GO TO 6.
5.CHANGE ENGINE OIL
1. Stop the engine.
2. Change engine oil. NOTE:
This symptom may occur when a large amount of gas oline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detect ed after changing engine oil or changing driving con-
dition.
>>INSPECTION END
6.CHECK FUEL PRESSURE
Check fuel pressure. (Refer to EC-487, "Fuel Pressure Check"
.)
OK or NG
OK >> GO TO 9.
NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to EC-487, "Fuel Pressure Check"
.
GO TO 8.
NG (Fuel pressure is too low)>>GO TO 7.
7.DETECT MALFUNCTIONING PART
1. Check the following.
- Clogged and bent fuel hose and fuel tube
- Clogged fuel filter
- Fuel pump and its circuit (Refer to EC-487, "Fuel Pressure Check"
.)
2. If NG, repair or replace the malfunctioning part. (Refer to EC-487, "Fuel Pressure Check"
.)
If OK, replace fuel pressure regulator.
Revision: December 20092009 QX56
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EC-78
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>> GO TO 8.
8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B](/img/42/57031/w960_57031-1404.png "INFINITI QX56 2009 Factory Service Manual
EC-78
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
>> GO TO 8.
8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B")
EC-78
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
>> GO TO 8.
8.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 9.
9.PERFORM POWER BALANCE TEST
1. Perform “POWER BALANCE” in “ACTIVE TEST” mode.
2. Make sure that the each cylinder produces a momentary engine speed drop.
OK or NG
OK >> GO TO 12.
NG >> GO TO 10.
10.DETECT MALFUNCTIONING PART
1. Check the following.
- Ignition coil and its circuit (Refer to EC-404, "Diagnosis Procedure"
.)
- Fuel injector and its circuit (Refer to EC-392, "Diagnosis Procedure"
.)
- Intake air leakage
- Low compression pressure (Refer to EM-23, "Checking Compression Pressure"
.)
2. If NG, repair or replace the malfunctioning part.
If OK, replace fuel injector. (It may be caus ed by leakage from fuel injector or clogging.)
>> GO TO 11.
11 .CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> GO TO 12.
12.CHECK A/F SENSOR 1 FUNCTION
Perform all DTC Confirmation Procedure related with A/F sensor 1.
For DTC P0130, P0150, refer to EC-136, "DTC Confirmation Procedure"
.
For DTC P0131, P0151, refer to EC-140, "DTC Confirmation Procedure"
.
For DTC P0132, P0132, refer to EC-143, "DTC Confirmation Procedure"
.
For DTC P0133, P0153, refer to EC-146, "DTC Confirmation Procedure"
.
For DTC P2A00, P2A03, refer to EC-377, "DTC Confirmation Procedure"
.
OK or NG
OK >> GO TO 15.
NG >> GO TO 13.
13.CHECK A/F SENSOR 1 CIRCUIT
Perform Diagnostic Procedure according to corresponding DTC.
>> GO TO 14.
14.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
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OK >>
INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR
1](/img/42/57031/w960_57031-1405.png "INFINITI QX56 2009 Factory Service Manual
TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-79
< COMPONENT DIAGNOSIS > [VK56DE]
C
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F
G H
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OK >>
INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR
1")
TROUBLE DIAGNOSIS - SPECIFICATION VALUEEC-79
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OK >>
INSPECTION END
NG >> GO TO 15.
15.DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR
1. Stop the engine.
2. Disconnect ECM harness connector. Check pin term inal and connector for damage, and then reconnect it.
>> GO TO 16.
16.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”
1. Start engine.
2. Select “A/F ALPHA-B1”, “A/F AL PHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG >> Detect malfunctioning part according to EC-475, "Symptom Matrix Chart"
.
17.CHECK “B/FUEL SCHDL”
Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” m ode, and make sure that the indication is within the
SP value.
OK or NG
OK >> INSPECTION END
NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.
18.DETECT MALFUNCTIONING PART
1. Check for the cause of large engine friction. Refer to the following.
- Engine oil level is too high
- Engine oil viscosity
- Belt tension of power steering, alternator, A/C compressor, etc. is excessive
- Noise from engine
- Noise from transmission, etc.
2. Check for the cause of insufficient combustion. Refer to the following.
- Valve clearance malfunction
- Intake valve timing control function malfunction
- Camshaft sprocket installation malfunction, etc.
>> Repair or replace malfunctioning part, and then GO TO 30.
19.CHECK INTAKE SYSTEM
Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
Crushed air ducts
Malfunctioning seal of air cleaner element
Uneven dirt of air cleaner element
Improper specification of intake air system
OK or NG
OK >> GO TO 21.
NG >> Repair or replace malfunctioning part, and then GO TO 20.
20.CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”
Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/F UEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and
make sure that the each indication is within the SP value.
OK or NG
OK >> INSPECTION END
NG (“B/FUEL SCHDL” is more, “A/F ALPHA-B1”, “A /F ALPHA-B2” are less than the SP value)>>GO TO 21.
21.DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR
1. Stop the engine.
Revision: December 20092009 QX56