2004 INFINITI QX56 sensor

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.

BASIC SERVICE PROCEDURE
EC-41
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Revision: August 20072004 QX56
21. CHECK AIR FUEL RATIO (A/F) SENSOR 1 HARNESS
1. Turn ignition switch OFF and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect A/F sensor 1 harness connector.
4. Check harness continuity between the following terminals. Refer to EC-431, "
Wiring Diagram" .
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 22.
NG >> 1. Repair open circuit or short to ground or short to power in harness or connectors between ECM
and A/F sensor 1.
2. GO TO 4.
22. PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING
1. Reconnect ECM harness connector.
2. Perform EC-44, "
Accelerator Pedal Released Position Learning" .
>> GO TO 23.
23. PERFORM THROTTLE VALVE CLOSED POSITION LEARNING
Perform EC-44, "
Throttle Valve Closed Position Learning" .
>> GO TO 24.
24. PERFORM IDLE AIR VOLUME LEARNING
Refer to EC-44, "
Idle Air Volume Learning" .
Is Idle Air Volume Learning carried out successfully?
Ye s o r N o
Yes (With CONSULT-II)>>GO TO 25.
Yes (Without CONSULT-II)>>GO TO 26.
No >> 1. Follow the instruction of Idle Air Volume Learning.
2. GO TO 4.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal
1161 76
275277
42424
535557
656658
Continuity should exist.

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
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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.

EC-44Revision: August 2007
BASIC SERVICE PROCEDURE
2004 QX56
32. ERASE UNNECESSARY DTC
After this inspection, unnecessary DTC might be displayed.
Erase the stored memory in ECM and TCM. Refer to EC-62, "
HOW TO ERASE EMISSION-RELATED DIAG-
NOSTIC INFORMATION" and AT- 4 0 , "HOW TO ERASE DTC" .
>> GO TO 4.
33. CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but
this is a rare case.)
2. Perform initialization of IVIS (NATS) system and registration of all IVIS (NATS) ignition key IDs. Refer to
BL-140, "
ECM Re-communicating Function" .
>> GO TO 4.
Accelerator Pedal Released Position LearningUBS00GZM
DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accel-
erator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time
harness connector of accelerator pedal position sensor or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF wait at least 10 seconds.
Throttle Valve Closed Position LearningUBS00GZN
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by
monitoring the throttle position sensor output signal. It must be performed each time harness connector of
electric throttle control actuator or ECM is disconnected.
OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.
Idle Air Volume LearningUBS00GZO
DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range. It must be performed under any of the following conditions:

Each time electric throttle control actuator or ECM is replaced.

Idle speed or ignition timing is out of specification.
PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

Battery voltage: More than 12.9V (At idle)

Engine coolant temperature: 70 - 100°C (158 - 212°F)

PNP switch: ON

Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)

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

ON BOARD DIAGNOSTIC (OBD) SYSTEM
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Revision: August 20072004 QX56
ON BOARD DIAGNOSTIC (OBD) SYSTEMPFP:00028
IntroductionUBS00GZQ
The ECM has an on board diagnostic system, which detects malfunctions related to engine sensors or actua-
tors. The ECM also records various emission-related diagnostic information including:
The above information can be checked using procedures listed in the table below.
×: Applicable —: Not applicable
*: When DTC and 1st trip DTC simultaneously appear on the display, they cannot be clearly distinguished from each other.
The malfunction indicator lamp (MIL) on the instrument panel lights up when the same malfunction is detected
in two consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to EC-77,
"Fail-safe Chart" .)
Two Trip Detection LogicUBS00GZR
When a malfunction is detected for the first time, 1st trip DTC and 1st trip Freeze Frame data are stored in the
ECM memory. The MIL will not light up at this stage. <1st trip>
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in
the ECM memory, and the MIL lights up. The MIL lights up at the same time when the DTC is stored. <2nd
trip> The “trip” in the “Two Trip Detection Logic” means a driving mode in which self-diagnosis is performed
during vehicle operation. Specific on board diagnostic items will cause the ECM to light up or blink the MIL,
and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
×: Applicable —: Not applicable
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.
Emission-related diagnostic information SAE Mode
Diagnostic Trouble Code (DTC) Mode 3 of SAE J1979
Freeze Frame data Mode 2 of SAE J1979
System Readiness Test (SRT) code Mode 1 of SAE J1979
1st Trip Diagnostic Trouble Code (1st Trip DTC) Mode 7 of SAE J1979
1st Trip Freeze Frame data
Test values and Test limits Mode 6 of SAE J1979
Calibration ID Mode 9 of SAE J1979
DTC 1st trip DTCFreeze Frame
data1st trip Freeze
Frame dataSRT code Test value
CONSULT-II×× × × ×—
GST×× ×—××
ECM××*— ———
ItemsMIL DTC 1st trip DTC
1st trip 2nd trip
1st trip
displaying2nd trip
displaying1st trip
displaying2nd trip
display-
ing BlinkingLighting
upBlinkingLighting
up
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected×———— —×—
Misfire (Possible three way catalyst
damage) — DTC: P0300 - P0308 is
being detected——×——×——
One trip detection diagnoses (Refer
to EC-8, "
INDEX FOR DTC" .)—×——×———
Except above — — —×—××—

EC-50Revision: August 2007
ON BOARD DIAGNOSTIC (OBD) SYSTEM
2004 QX56
The fail-safe function also operates when above diagnoses except MIL circuit are detected, and demands the
driver to repair the malfunction.
Emission-related Diagnostic InformationUBS00GZS
EMISSION-RELATED DIAGNOSTIC INFORMATION ITEMS
×: Applicable —: Not applicable Engine operating condition in fail-safe mode Engine speed will not rise more than 2,500 rpm due to the fuel cut
Items
(CONSULT-II screen terms)DTC*
1
SRT codeTest value/
Test limit
(GST only)1st trip DTCReference
page CONSULT-II
GST*
2ECM*3
CAN COMM CIRCUIT U1000
1000*5———EC-135
CAN COMM CIRCUIT U1001
1001*5——×EC-135
NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED.P0000 0000————
HO2S2 HTR (B1) P0037 0037×××EC-138
HO2S2 HTR (B1) P0038 0038×××EC-138
HO2S2 HTR (B2) P0057 0057×××EC-138
HO2S2 HTR (B2) P0058 0058×××EC-138
MAF SEN/CIRCUIT P0101 0101 — — —EC-146
MAF SEN/CIRCUIT P0102 0102 — — —EC-154
MAF SEN/CIRCUIT P0103 0103 — — —EC-154
IAT SEN/CIRCUIT P0112 0112 — —×EC-161
IAT SEN/CIRCUIT P0113 0113 — —×EC-161
ECT SEN/CIRCUIT P0117 0117 — — —EC-165
ECT SEN/CIRCUIT P0118 0118 — — —EC-165
TP SEN 2/CIRC P0122 0122 — — —EC-171
TP SEN 2/CIRC P0123 0123 — — —EC-171
ECT SENSOR P0125 0125 — — —EC-178
IAT SENSOR P0127 0127 — —×EC-181
THERMSTAT FNCTN P0128 0128 — —×EC-184
HO2S2 (B1) P0138 0138 —××EC-186
HO2S2 (B1) P0139 0139×××EC-196
HO2S2 (B2) P0158 0158 —××EC-186
HO2S2 (B2) P0159 0159×××EC-196
FUEL SYS-LEAN-B1 P0171 0171 — —×EC-208
FUEL SYS-RICH-B1 P0172 0172 — —×EC-217
FUEL SYS-LEAN-B2 P0174 0174 — —×EC-208
FUEL SYS-RICH-B2 P0175 0175 — —×EC-217
FTT SENSOR P0181 0181 — —×EC-225
FTT SEN/CIRCUIT P0182 0182 — —×EC-231
FTT SEN/CIRCUIT P0183 0183 — —×EC-231
TP SEN 1/CIRC P0222 0222 — — —EC-236
TP SEN 1/CIRC P0223 0223 — — —EC-236
MULTI CYL MISFIRE P0300 0300 — —×EC-243
CYL 1 MISFIRE P0301 0301 — —×EC-243
CYL 2 MISFIRE P0302 0302 — —×EC-243