2005 INFINITI QX4 service

BASIC SERVICE PROCEDURE
EC-93
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Revision: October 20052005 QX5613. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried
out successfully. In this case, find the cause of the incident by referring to the DIAGNOSTIC PROCE-
DURE below.
DIAGNOSTIC PROCEDURE
If idle air volume learning cannot be performed successfully, proceed as follows:
1.Check that throttle valve is fully closed.
2.Check PCV valve operation.
3.Check that downstream of throttle valve is free from air leakage.
4.When the above three items check out OK, engine component parts and their installation condi-
tion are questionable. Check and eliminate the cause of the incident.
It is useful to perform EC-146, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
5.If any of the following conditions occur after the engine has started, eliminate the cause of the
incident and perform Idle Air Volume Learning all over again:

Engine stalls.

Erroneous idle.
Fuel Pressure CheckUBS00L01
FUEL PRESSURE RELEASE
With CONSULT-II
1. Turn ignition switch ON.
2. Perform “FUEL PRESSURE RELEASE” in “WORK SUPPORT”
mode with CONSULT-II.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel
pressure.
5. Turn ignition switch OFF.
Without CONSULT-II
1. Remove fuel pump fuse located in IPDM E/R.
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel
pressure.
4. Turn ignition switch OFF.
5. Reinstall fuel pump fuse after servicing fuel system.
ITEM SPECIFICATION
Idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5° BTDC (in P or N position)
SEF 2 14 Y
BBIA0380E

EC-94Revision: October 2005
BASIC SERVICE PROCEDURE
2005 QX56
FUEL PRESSURE CHECK
CAUTION:

Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.

Be careful not to scratch or get the fuel hose connection area dirty when servicing, so that the
quick connector o-ring maintains sealability.

Use Fuel Pressure Gauge Kit J-44321 and Fuel Pressure Adapter J-44321-6 to check fuel pressure.

Do not perform fuel pressure check with electrical system operating (i.e. lights, rear defog, A/C,
etc.). Fuel pressure gauge may indicate false readings due to varying engine loads and changes in
manifold vacuum.
NOTE:
Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel pres-
sure cannot be completely released because JA60 models do not have fuel return system.
1. Release fuel pressure to zero. Refer to EC-93, "
FUEL PRESSURE RELEASE" .
2. Remove engine cover.
3. Remove fuel hose using Quick Connector Release J-45488. Refer to EM-15, "
INTAKE MANIFOLD" .

Do not twist or kink fuel hose because it is plastic hose.

Do not remove fuel hose from quick connector.

Keep fuel hose connections clean.
4. Install Fuel Pressure Adapter J-44321-6 and Fuel Pressure
Gauge (from kit J-44321) as shown in figure.

Do not distort or bend fuel rail tube when installing fuel pres-
sure gauge adapter.

When reconnecting fuel hose, check the original fuel hose for
damage and abnormality.
5. Turn ignition switch ON (reactivate fuel pump), and check for
fuel leakage.
6. Start engine and check for fuel leakage.
7. Read the indication of fuel pressure gauge.

During fuel pressure check, check for fuel leakage from fuel
connection every 3 minutes.
8. If result is unsatisfactory, go to next step.
9. Check the following.

Fuel hoses and fuel tubes for clogging

Fuel filter for clogging

Fuel pump

Fuel pressure regulator for clogging
If OK, replace fuel pressure regulator.
If NG, repair or replace.
10. Before disconnecting Fuel Pressure Gauge and Fuel Pressure Adapter J-44321-6, release fuel pressure
to zero. Refer to EC-93, "
FUEL PRESSURE RELEASE" . At idling:
Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)
BBIA0390E

TROUBLE DIAGNOSIS
EC-97
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Revision: October 20052005 QX56
Detailed Flow
1. GET INFORMATION FOR SYMPTOM
Get the detailed information from the customer about the symptom (the condition and the environment when
the incident/malfunction occurred) using the EC-100, "
Worksheet Sample" .
>> GO TO 2.
2. CHECK DTC*1
1. Check DTC*1 .
2. Perform the following procedure if DTC*
1 is displayed.
–Record DTC*1 and freeze frame data*2 . (Print them out with CONSULT-II or GST.)
–Erase DTC*1 . (Refer to EC-62, "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION"
.)
–Study the relationship between the cause detected by DTC*1 and the symptom described by the cus-
tomer. (Symptom Matrix Chart is useful. Refer to EC-104, "
Symptom Matrix Chart" .)
3. Check related service bulletins for information.
Is any symptom described and any DTC detected?
Symptom is described, DTC*1 is displayed>>GO TO 3.
Symptom is described, DTC*
1 is not displayed>>GO TO 4.
Symptom is not described, DTC*
1 is displayed>>GO TO 5.
3. CONFIRM THE SYMPTOM
Try to confirm the symptom described by the customer (except MIL ON).
DIAGNOSIS WORK SHEET is useful to verify the incident.
Connect CONSULT-II to the vehicle in “DATA MONITOR (AUTO TRIG)” mode and check real time diagnosis
results.
Verify relation between the symptom and the condition when the symptom is detected.
>> GO TO 5.
4. CONFIRM THE SYMPTOM
Try to confirm the symptom described by the customer.
DIAGNOSIS WORK SHEET is useful to verify the incident.
Connect CONSULT-II to the vehicle in “DATA MONITOR (AUTO TRIG)” mode and check real time diagnosis
results.
Verify relation between the symptom and the condition when the symptom is detected.
>> GO TO 6.

EC-98Revision: October 2005
TROUBLE DIAGNOSIS
2005 QX56
5. PERFORM DTC CONFIRMATION PROCEDURE
Perform DTC Confirmation Procedure for the displayed DTC*
1 , and then make sure that DTC*1 is detected
again.
At this time, always connect CONSULT-II to the vehicle, and check diagnostic results in real time on “DATA
MONITOR (AUTO TRIG)”.
If two or more DTCs*
1 are detected, refer to EC-101, "DTC Inspection Priority Chart" and determine trouble
diagnosis order.
NOTE:

Freeze frame data*2 is useful if the DTC*1 is not detected.

Perform Overall Function Check if DTC Confirmation Procedure is not included on Service Manual. This
simplified check procedure is an effective alternative though DTC*
1 cannot be detected during this check.
If the result of Overall Function Check is NG, it is the same as the detection of DTC*
1 by DTC Confirma-
tion Procedure.
Is DTC*
1 detected?
Yes >> GO TO 10.
No >> Check according to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
6. PERFORM BASIC INSPECTION
Perform EC-72, "
Basic Inspection" .
With CONSULT-II>>GO TO 7.
Without CONSULT-II>>GO TO 9.
7. PERFORM DATA MONITOR (SPEC) MODE
With CONSULT-II
Make sure that “MAS A/F SE-B1”, “B/FUEL SCHDL”, and “A/F
ALPHA-B1”, “A/F ALPHA-B2” are within the SP value using CON-
SULT-II “DATA MONITOR (SPEC)” mode. Refer to EC-146, "
TROU-
BLE DIAGNOSIS - SPECIFICATION VALUE" .
Are they within the SP value?
Yes >> GO TO 9.
No >> GO TO 8.
8. DETECT MALFUNCTIONING PART BY TROUBLE DIAGNOSIS - SPECIFICATION VALUE
Detect malfunctioning part according to EC-147, "
Diagnostic Procedure" .
Is malfunctioning part detected?
Yes >> GO TO 11.
No >> GO TO 9.
9. DETECT MALFUNCTIONING SYSTEM BY SYMPTOM MATRIX CHART
Detect malfunctioning system according to EC-104, "
Symptom Matrix Chart" based on the confirmed symp-
tom in step 4, and determine the trouble diagnosis order based on possible causes and symptom.
>> GO TO 10.
SEF 6 01 Z

TROUBLE DIAGNOSIS
EC-129
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Revision: October 20052005 QX56
5. Touch “ENGINE”.
If “ENGINE” is not indicated, go to GI-39, "
CONSULT-II Data
Link Connector (DLC) Circuit" .
6. Perform each diagnostic test mode according to each service
procedure.
For further information, see the CONSULT-II Operation Manual.
WORK SUPPORT MODE
Work Item
BCIA0030E
BCIA0031E
WORK ITEM CONDITION USAGE
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
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
SELF-LEARNING CONT

THE COEFFICIENT OF SELF-LEARNING CONTROL
MIXTURE RATIO RETURNS TO THE ORIGINAL COEF-
FICIENT.When clearing the coefficient of
self-learning control value
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-
II WILL DISCONTINUE IT AND DISPLAY APPROPRI-
ATE INSTRUCTION.
NOTE:
WHEN STARTING ENGINE, CONSULT-II MAY DISPLAY
“BATTERY VOLTAGE IS LOW. CHARGE BATTERY”,
EVEN IN USING CHARGED BATTERY.When detecting EVAP vapor leak
point of EVAP system
VIN REGISTRATION

IN THIS MODE, VIN IS REGISTERED IN ECM When registering VIN in ECM

EC-130Revision: October 2005
TROUBLE DIAGNOSIS
2005 QX56
*: 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-49, "EMISSION-RELATED DIAGNOSTIC INFORMA-
TION ITEMS" .
Freeze Frame Data and 1st Trip Freeze Frame Data
*: The item is the same as that of 1st trip freeze frame data.TARGET IDLE RPM ADJ*

IDLE CONDITION When setting target idle speed
TARGET IGN TIM ADJ*

IDLE CONDITION When adjusting target ignition tim-
ing WORK ITEM CONDITION USAGE
Freeze frame data
item*Description
DIAG TROUBLE
CODE
[PXXXX]

The engine control component part/control system has a trouble code, it is displayed as “PXXXX”. (Refer
to EC-8, "
INDEX FOR DTC" .)
FUEL SYS-B1

“Fuel injection system status” at the moment a malfunction is detected is displayed.

One mode in the following is displayed.
“Mode2”: Open loop due to detected system malfunction
“Mode3”: Open loop due to driving conditions (power enrichment, deceleration enleanment)
“Mode4”: Closed loop - using oxygen sensor(s) as feedback for fuel control
“Mode5”: Open loop - has not yet satisfied condition to go to closed loop FUEL SYS-B2
CAL/LD VALUE [%]

The calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP
[°C] or [°F]

The engine coolant temperature at the moment a malfunction is detected is displayed.
L-FUEL TRM-B1 [%]

“Long-term fuel trim” at the moment a malfunction is detected is displayed.

The long-term fuel trim indicates much more gradual feedback compensation to the base fuel schedule
than short-term fuel trim. L-FUEL TRM-B2 [%]
S-FUEL TRM-B1 [%]

“Short-term fuel trim” at the moment a malfunction is detected is displayed.

The short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel
schedule. S-FUEL TRM-B2 [%]
ENGINE SPEED
[rpm]

The engine speed at the moment a malfunction is detected is displayed.
VEHICL SPEED
[km/h] or [mph]

The vehicle speed at the moment a malfunction is detected is displayed.
ABSOL TH-P/S
[%]

The throttle valve opening at the moment a malfunction is detected is displayed.
B/FUEL SCHDL
[msec]

The base fuel schedule at the moment a malfunction is detected is displayed.
INT/A TEMP SE
[°C] or [°F]

The intake air temperature at the moment a malfunction is detected is displayed.

TROUBLE DIAGNOSIS
EC-139
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Revision: October 20052005 QX56
Generic Scan Tool (GST) FunctionUBS00L0C
DESCRIPTION
Generic Scan Tool (OBDII scan tool) complying with SAE J1978 has
8 different functions explained below.
ISO9141 is used as the protocol.
The name GST or Generic Scan Tool is used in this service manual.
FUNCTION
SEF 1 39 P
Diagnostic test mode Function
Service $01 READINESS TESTSThis diagnostic service gains access to current emission-related data values, including
analog inputs and outputs, digital inputs and outputs, and system status information.
Service $02 (FREEZE DATA)This diagnostic service gains access to emission-related data value which were stored by
ECM during the freeze frame. For details, refer to EC-54, "
FREEZE FRAME DATA AND
1ST TRIP FREEZE FRAME DATA" .
Service $03 DTCsThis diagnostic service gains access to emission-related power train trouble codes which
were stored by ECM.
Service $04 CLEAR DIAG INFOThis diagnostic service can clear all emission-related diagnostic information. This
includes:

Clear number of diagnostic trouble codes (Service $01)

Clear diagnostic trouble codes (Service $03)

Clear trouble code for freeze frame data (Service $01)

Clear freeze frame data (Service $02)

Reset status of system monitoring test (Service $01)

Clear on board monitoring test results (Service $06 and $07)
Service $06 (ON BOARD TESTS)This diagnostic service accesses the results of on board diagnostic monitoring tests of
specific components/systems that are not continuously monitored.
Service $07 (ON BOARD TESTS)This diagnostic service enables the off board test drive to obtain test results for emission-
related powertrain components/systems that are continuously monitored during normal
driving conditions.
Service $08 —This diagnostic service can close EVAP system in ignition switch ON position (Engine
stopped). When this diagnostic service is performed, the EVAP canister vent control
valve can be closed.
In the following conditions, this diagnostic service cannot function.

Low ambient temperature

Low battery voltage

Engine running

Ignition switch OFF

Low fuel temperature

Too much pressure is applied to EVAP system
Service $09 (CALIBRATION ID)This diagnostic service enables the off-board test device to request specific vehicle infor-
mation such as Vehicle Identification Number (VIN) and Calibration IDs.

EC-140Revision: October 2005
TROUBLE DIAGNOSIS
2005 QX56
INSPECTION PROCEDURE
1. Turn ignition switch OFF.
2. Connect GST to data link connector, which is located under LH
dash panel near the hood opener handle.
3. Turn ignition switch ON.
4. Enter the program according to instruction on the screen or in
the operation manual.
(*: Regarding GST screens in this section, sample screens are
shown.)
5. Perform each diagnostic service according to each service pro-
cedure.
For further information, see the GST Operation Manual of
the tool maker.
BBIA0369E
SEF 3 98 S
SEF 4 16 S