2004 INFINITI QX56 stop start

EC-40Revision: August 2007
BASIC SERVICE PROCEDURE
2004 QX56
19. CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION
With CONSULT-II
1. Turn ignition switch OFF and wait at a least 10 seconds.
2. Start engine and warm it up to normal operating temperature.
3. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in D position with “OD” OFF.
NOTE:
Keep the accelerator pedal as steady as possible during the cruising.
4. Set “OD” ON, then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30
MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
5. Repeat steps 3 to 4 five times.
6. Stop the vehicle and connect CONSULT-II to the vehicle.
7. Make sure that no (1st trip) DTC is displayed in “SELF-DIAG RESULTS” mode.
OK or NG
OK >>INSPECTION END
NG >> GO TO 21.
20. CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION
With GST
1. Turn ignition switch OFF and wait at a least 10 seconds.
2. Start engine and warm it up to normal operating temperature.
3. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in D position with “OD” OFF.
NOTE:
Keep the accelerator pedal as steady as possible during the cruising.
4. Set “OD” ON, then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30
MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
5. Repeat steps 3 to 4 five times.
6. Stop the vehicle and connect GST to the vehicle.
7. Make sure that no (1st trip) DTC is displayed.
OK or NG
OK >>INSPECTION END
NG >> GO TO 21.

EC-42Revision: August 2007
BASIC SERVICE PROCEDURE
2004 QX56
25. CHECK CO%
With CONSULT-II
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
2. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
3. Select “ENG COOLANT TEMP” in “ACTIVE TEST” mode.
4. Set “ENG COOLANT TEMP” to 5°C (41°F) by touching “DWN”
and “Qd”.
5. Start engine and rev it (2,000 to 3,000 rpm) two or three times
under no load, then run engine at idle speed.
6. Check CO%.
OK or NG
OK >> GO TO 28.
NG >> GO TO 27.
26. CHECK CO%
Without CONSULT-II
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
2. Turn ignition switch OFF.
3. Disconnect engine coolant temperature sensor harness connector.
4. Connect a resistor (4.4 kΩ) between terminals of engine coolant
temperature sensor harness connector.
5. Start engine and rev it (2,000 to 3,000 rpm) two or three times
under no load, then run engine at idle speed.
6. Check CO%.
7. After checking CO%, turn ignition switch OFF, disconnect the
resistor from the terminals of engine coolant temperature sensor
harness connector, and then connect engine coolant tempera-
ture sensor harness connector to engine coolant temperature
sensor.
OK or NG
OK >> GO TO 28.
NG >> GO TO 27.
27. RECONNECT AIR FUEL RATIO (A/F) SENSOR 1 HARNESS CONNECTOR
1. Turn ignition switch OFF.
2. Reconnect A/F sensor 1 harness connector.
>> GO TO 31.
28. REPLACE AIR FUEL RATIO (A/F) SENSOR 1
1. Stop engine.
2. Replace A/F sensor 1 on the malfunctioning bank.
With CONSULT-II>>GO TO 29.
Without CONSULT-II>>GO TO 30.Idle CO: 3 − 11% and engine runs smoothly.
SEF 1 72 Y
Idle CO: 3 − 11% and engine runs smoothly.
SEF 9 82 UA

BASIC SERVICE PROCEDURE
EC-43
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Revision: August 20072004 QX56
29. CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION
With CONSULT-II
1. Turn ignition switch OFF and wait at a least 10 seconds.
2. Start engine and warm it up to normal operating temperature.
3. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in D position with “OD” OFF.
NOTE:
Keep the accelerator pedal as steady as possible during the cruising.
4. Set “OD” ON, then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30
MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
5. Repeat steps 3 to 4 five times.
6. Stop the vehicle and connect CONSULT-II to the vehicle.
7. Make sure that no (1st trip) DTC is displayed in “SELF-DIAG RESULTS” mode.
OK or NG
OK >> GO TO 4.
NG >> GO TO 31.
30. CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION
With GST
1. Turn ignition switch OFF and wait at a least 10 seconds.
2. Start engine and warm it up to normal operating temperature.
3. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in D position with “OD” OFF.
NOTE:
Keep the accelerator pedal as steady as possible during the cruising.
4. Set “OD” ON, then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30
MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
5. Repeat steps 3 to 4 five times.
6. Stop the vehicle and connect GST to the vehicle.
7. Make sure that no (1st trip) DTC is displayed.
OK or NG
OK >> GO TO 4.
NG >> GO TO 31.
31. DETECT MALFUNCTIONING PART
Check the following.

Check fuel pressure regulator, and repair or replace if necessary. Refer to EC-47, "FUEL PRESSURE
CHECK" .

Check mass air flow sensor and its circuit, and repair or replace if necessary. Refer to EC-146 and EC-
154 .

Check injector and its circuit, and repair or replace if necessary. Refer to EC-595 .

Check engine coolant temperature sensor and its circuit, and repair or replace if necessary. Refer to EC-
165 and EC-178 .
OK or NG
OK >> GO TO 33.
NG >> 1. Repair or replace.
2. GO TO 32.

BASIC SERVICE PROCEDURE
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Revision: August 20072004 QX56
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started, the headlamp will not be illuminated.

Steering wheel: Neutral (Straight-ahead position)

Vehicle speed: Stopped

Transmission: Warmed-up
For models with CONSULT-II, drive vehicle until “FLUID TEMP SE” in “DATA MONITOR” mode of “A/T”
system indicates less than 0.9V.
For models without CONSULT-II, drive vehicle for 10 minutes.
OPERATION PROCEDURE
With CONSULT-II
1. Perform EC-44, "Accelerator Pedal Released Position Learning" .
2. Perform EC-44, "
Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.
6. Touch “START” and wait 20 seconds.
7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If
“CMPLT” is not displayed, Idle Air Volume Learning will not be
carried out successfully. In this case, find the cause of the inci-
dent by referring to the Diagnostic Procedure below.
8. Rev up the engine two or three times and make sure that idle
speed and ignition timing are within the specifications.
Without CONSULT-II
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.
1. Perform EC-44, "
Accelerator Pedal Released Position Learning" .
SEF 2 17 Z
SEF 4 54 Y
ITEM SPECIFICATION
Idle speed 650±50 rpm (in P or N position)
Ignition timing 15±5° BTDC (in P or N position)
MBIB0238E

EC-46Revision: August 2007
BASIC SERVICE PROCEDURE
2004 QX56
2. Perform EC-44, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
13. 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-123, "
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 CheckUBS00GZP
FUEL PRESSURE RELEASE
With CONSULT-II
1. Turn ignition switch ON.
ITEM SPECIFICATION
Idle speed 650±50 rpm (in P or N position)
Ignition timing 15±5° BTDC (in P or N position)
SEC8 97 C

ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-63
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Revision: August 20072004 QX56
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.
SEF 5 43 X
SEF 2 17 U

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

EC-78Revision: August 2007
TROUBLE DIAGNOSIS
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.
P0122
P0123
P0222
P0223
P2135Throttle position sensor The ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor.
P1121 Electric throttle control
actuator(When electric throttle control actuator does not function properly due to the return spring
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the
idle position. The engine speed will not rise more than 2,000 rpm.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(When ECM detects the throttle valve is stuck open:)
While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops,
the engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or
more.
P1122 Electric throttle control
functionECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1124
P1126Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1128 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P1229 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2122
P2123
P2127
P2128
P2138Accelerator pedal position
sensorThe ECM controls the electric throttle control actuator in regulating the throttle opening in
order for the idle position to be within +10 degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal
condition.
So, the acceleration will be poor. DTC No. Detected items Engine operating condition in fail-safe mode
Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut