2004 INFINITI QX56 ignition

BASIC SERVICE PROCEDURE
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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.
FUEL PRESSURE CHECK
CAUTION:

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

Prepare pans or saucers under the disconnected fuel line because the fuel may spill out. The fuel
pressure cannot be completely released because A60 models do not have fuel return system.

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.
1. Release fuel pressure to zero. Refer to EC-46, "
FUEL PRESSURE RELEASE" .
2. Remove engine cover.
3. Remove fuel hose using Quick Connector Release J-45488.
Refer to EM-29, "
FUEL INJECTOR AND FUEL TUBE" .

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.
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BBIA0380E
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EC-48Revision: August 2007
BASIC SERVICE PROCEDURE
2004 QX56
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-46, "
FUEL PRESSURE RELEASE" . At idling:
Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)
BBIA0390E

EC-56Revision: August 2007
ON BOARD DIAGNOSTIC (OBD) SYSTEM
2004 QX56
*1: If completion of several SRTs is required, perform driving patterns (DTC confirmation procedure), one by one based on the pri ority for
models with CONSULT-II.
SRT Set Timing
SRT is set as “CMPLT” after self-diagnosis has been performed one or more times. Completion of SRT is
done regardless of whether the result is OK or NG. The set timing is different between OK and NG results and
is shown in the table below.
OK: Self-diagnosis is carried out and the result is OK.
NG: Self-diagnosis is carried out and the result is NG.
—: Self-diagnosis is not carried out.
When all SRT related self-diagnoses showed OK results in a single cycle (Ignition OFF-ON-OFF), the SRT will
indicate “CMPLT”. → Case 1 above
When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indicate
“CMPLT” at the time the respective self-diagnoses have at least one OK result. → Case 2 above
If one or more SRT related self-diagnoses showed NG results in 2 consecutive cycles, the SRT will also indi-
cate “CMPLT”. → Case 3 above
The table above shows that the minimum number of cycles for setting SRT as “INCMP” is one (1) for each
self-diagnosis (Case 1 & 2) or two (2) for one of self-diagnoses (Case 3). However, in preparation for the state
emissions inspection, it is unnecessary for each self-diagnosis to be executed twice (Case 3) for the following
reasons:

The SRT will indicate “CMPLT” at the time the respective self-diagnoses have one (1) OK result.

The emissions inspection requires “CMPLT” of the SRT only with OK self-diagnosis results.

When, during SRT driving pattern, 1st trip DTC (NG) is detected prior to “CMPLT” of SRT, the self-diagno-
sis memory must be erased from ECM after repair.

If the 1st trip DTC is erased, all the SRT will indicate “INCMP”.
NOTE:
SRT can be set as “CMPLT” together with the DTC(s). Therefore, DTC check must always be carried out
prior to the state emission inspection even though the SRT indicates “CMPLT”.
HO2S HTR 2 A/F sensor 1 heater P1031, P1032,
P1051, P1052
Heated oxygen sensor 2 heater P0037, P0038,
P0057, P0058 Item
(CONSULT-II indication)Performance
Priority
*1Required self-diagnostic items to set the SRT to “CMPLT”Corresponding DTC
No.
Self-diagnosis resultExample
DiagnosisIgnition cycle
← ON → OFF ← ON → OFF ← ON → OFF ← ON →
All OK Case 1 P0400 OK (1) — (1) OK (2) — (2)
P0402 OK (1) — (1) — (1) OK (2)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “CMPLT” “CMPLT” “CMPLT” “CMPLT”
Case 2 P0400 OK (1) — (1) — (1) — (1)
P0402 — (0) — (0) OK (1) — (1)
P1402 OK (1) OK (2) — (2) — (2)
SRT of EGR “INCMP” “INCMP” “CMPLT” “CMPLT”
NG exists Case 3 P0400 OK OK — —
P0402 — — — —
P1402 NG — NGNG
(Consecutive
NG)
(1st trip)
DTC1st trip DTC — 1st trip DTCDTC
(= MIL “ON”)
SRT of EGR “INCMP” “INCMP” “INCMP” “CMPLT”

EC-62Revision: August 2007
ON BOARD DIAGNOSTIC (OBD) SYSTEM
2004 QX56
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION
How to Erase DTC
With CONSULT-II
The emission related diagnostic information in the ECM can be erased by selecting “ERASE” in the “SELF-
DIAG RESULTS” mode with CONSULT-II.
If DTCs are displayed for both ECM and TCM (Transmission control module), they need to be erased individu-
ally from the ECM and TCM (Transmission control module).
NOTE:
If the DTC is not for A/T related items (see EC-8
), skip steps 2 through 4.
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. Turn CONSULT-II ON and touch “A/T”.
3. Touch “SELF-DIAG RESULTS”.
4. Touch “ERASE”. [The DTC in the TCM (Transmission control module) will be erased.] Then touch “BACK”
twice.
5. Touch “ENGINE”.
6. Touch “SELF-DIAG RESULTS”.
7. Touch “ERASE”. (The DTC in the ECM will be erased.)
With GST
The emission related diagnostic information in the ECM can be erased by selecting MODE 4 with GST.
NOTE:
If the DTC is not for A/T related items (see EC-8
), 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.
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ON BOARD DIAGNOSTIC (OBD) SYSTEM
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2. Perform AT-41, "HOW TO ERASE DTC (WITH GST)" . (The DTC in the TCM will be erased.)
3. Select MODE 4 with GST. (The DTC in the ECM will be erased.)
No Tools
NOTE:
If the DTC is not for A/T related items (see EC-8
), skip step 3.
1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once.
2. Wait at least 10 seconds and then turn it ON (engine stopped) again.
3. Perform AT-41, "
HOW TO ERASE DTC (NO TOOLS)" . (The DTC in the TCM will be erased.)
4. Change the diagnostic test mode from Mode II to Mode I by depressing the accelerator pedal. Refer to
EC-64, "
HOW TO SWITCH DIAGNOSTIC TEST MODE" .

If the battery is disconnected, the emission-related 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
–Others
Actual work procedures are explained using a DTC as an example. Be careful so that not only the DTC, but all
of the data listed above, are cleared from the ECM memory during work procedures.
IVIS (Infiniti Vehicle Immobilizer System — NATS)UBS00GZT

If the security indicator lights up with the ignition switch in
the ON position or “NATS MALFUNCTION” is displayed on
“SELF-DIAG RESULTS” screen, perform self-diagnostic
results mode with CONSULT-II using NATS program card.
Refer to BL-138, "
IVIS (INFINITI VEHICLE IMMOBILIZER
SYSTEM-NATS)" .

Confirm no self-diagnostic results of IVIS (NATS) is dis-
played before touching “ERASE” in “SELF-DIAG RESULTS”
mode with CONSULT-II.

When replacing ECM, initialization of IVIS (NATS) system
and registration of all IVIS (NATS) ignition key IDs must be
carried out with CONSULT-II using NATS program card.
Therefore, be sure to receive all keys from vehicle owner. Regarding the procedures of IVIS (NATS)
initialization and IVIS (NATS) ignition key ID registration, refer to CONSULT-II operation manual,
IVIS/NVIS.
Malfunction Indicator Lamp (MIL)UBS00GZU
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 DI-31, "
WAR NI NG L AMPS"
, or see EC-631, "MIL AND DATA LINK CONNECTOR" .
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 DIAGNOSTIC SYSTEM FUNCTION
The on board diagnostic system has the following 3 functions.
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EC-64Revision: August 2007
ON BOARD DIAGNOSTIC (OBD) SYSTEM
2004 QX56
When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting MIL up 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 control system malfunctions and MIL circuit is open by means
of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected, and demands the
driver to repair the malfunction.
HOW TO SWITCH DIAGNOSTIC TEST 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 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.
4. Fully release the accelerator pedal.
Diagnostic Test
ModeKEY and ENG.
Statu sFunction Explanation of Function
Mode I Ignition switch in
ON position
Engine stoppedBULB 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
WARNINGThis is a usual driving condition. When a malfunction is
detected twice in two consecutive driving cycles (two trip
detection 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 stoppedSELF-DIAGNOSTIC
RESULTSThis function allows DTCs and 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

TROUBLE DIAGNOSIS
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TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionUBS00GZW
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output signals are proper and stable. At the
same time, it is important that there are no malfunctions such as vac-
uum leaks, fouled spark plugs, or other malfunctions with the engine.
It is much more difficult to diagnose an incident that occurs intermit-
tently rather than continuously. Most intermittent incidents are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the incidents. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow EC-72, "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A Diagnostic Worksheet like the example
on EC-75
should be used.
Start your diagnosis by looking for conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
MEF036D
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TROUBLE DIAGNOSIS
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Fail-safe ChartUBS00GZY
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL lights up.
2
P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater

P0138 P0139 P0158 P0159 P1146 P1147 P1166 P1167 Heated oxygen sensor 2

P0441 EVAP control system purge flow monitoring

P0444 P0445 P1444 EVAP canister purge volume control solenoid valve

P0447 P1446 EVAP canister vent control valve

P0451 P0452 P0453 EVAP control system pressure sensor

P0550 Power steering pressure sensor

P0700 P0710 P0720 P0740 P0744 P0745 P1706 P1716 P1730 P1752 P1754 P1757 P1759 P1762 P1764 P1767
P1769 P1772 P1774 A/T related sensors and solenoid valves

P1031 P1032 P1051 P1052 A/F sensor 1 heater

P1065 ECM power supply

P1122 Electric throttle control function

P1124 P1126 P1128 Electric throttle control actuator

P1217 Engine over temperature (OVERHEAT)

P1271 P1272 P1273 P1274 P1276 P1278 P1279 P1281 P1282 P1283 P1284 P1286 P1288 P1289 A/F sensor 1

P1805 Brake switch
3

P0171 P0172 P0174 P0175 Fuel injection system function

P0300 - P0308 Misfire

P0420 P0430 Three way catalyst function

P0442 P0456 EVAP control system (SMALL LEAK, VERY SMALL LEAK)

P0455 EVAP control system (GROSS LEAK)

P0506 P0507 Idle speed control system

P1121 Electric throttle control actuator

P1148 P1168 Closed loop control

P1211 TCS control unit

P1212 TCS communication line

P1564 ICC steering switch/ASCD steering switch

P1568 ICC command value

P1572 ICC brake switch/ASCD brake switch

P1574 ICC vehicle speed sensor/ASCD vehicle speed sensor Priority Detected items (DTC)
DTC No. Detected items Engine operating condition in fail-safe mode
P0101
P0102
P0103Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118Engine coolant tempera-
ture sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning
ignition switch ON or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or START40°C (104°F)
More than approx. 4 minutes after
ignition ON or START80°C (176°F)
Except as shown above40 - 80°C (104 - 176°F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling
fan operates while engine is running.