2001 INFINITI QX4 ignition

32 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1)/(bank 2).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)/(B2)º in ªDATA MONITORº mode.
6. Maintaining engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1)/(bank 2).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 63 or 62 and ground.
6. Make sure that voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000 rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©GO TO 3.
NG©GO TO 33.
33 DETECT MALFUNCTIONING PART
Check the following.
IConnect heated oxygen sensor 1 (front) harness connectors to heated oxygen sensor 1 (front).
ICheck fuel pressure regulator. Refer to EC-40.
ICheck mass air flow sensor and its circuit. Refer to EC-150.
ICheck injector and its circuit. Refer to EC-616.
Clean or replace if necessary.
ICheck engine coolant temperature sensor and its circuit. Refer to EC-187.
ICheck ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-56

SEF452Y
Idle Air Volume LearningNBEC0642
SEF454Y
SEF455Y
DESCRIPTIONNBEC0642S01ªIdle Air Volume Learningº is an operation to learn the idle air vol-
ume that keeps each engine within the specific range. It must be
performed under any of the following conditions:
IEach time IACV-AAC valve, throttle body or ECM is replaced.
IIdle speed or ignition timing is out of specification.
PRE-CONDITIONINGNBEC0642S02Before performing ªIdle Air Volume Learningº, 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.
IBattery voltage: More than 12.9V (At idle)
IEngine coolant temperature: 70 - 99ÉC (158 - 210ÉF)
IPNP switch: ON
IElectric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime running light systems, if
the parking brake is applied before the engine is started the
headlamp will not illuminate.
ICooling fan motor: Not operating
ISteering wheel: Neutral (Straight-ahead position)
IVehicle speed: Stopped
ITransmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until ªFLUID
TEMP SEº in ªDATA MONITORº mode of ªA/Tº system indi-
cates less than 0.9V.
For A/T models without CONSULT-II, drive vehicle for 10 min-
utes.
OPERATION PROCEDURENBEC0642S03With CONSULT-IINBEC0642S03011. Turn ignition switch ªONº and wait at least 1 second.
2. Turn ignition switch ªOFFº and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic ªPRE-CONDITION-
INGº (previously mentioned) are in good order.
5. Turn ignition switch ªOFFº and wait at least 10 seconds.
6. Start the engine and let it idle for at least 30 seconds.
7. Select ªIDLE AIR VOL LEARNº in ªWORK SUPPORTº mode.
8. Touch ªSTARTº and wait 20 seconds.
9. Make sure that ªCMPLTº is displayed on CONSULT-II screen.
If ªINCMPº is displayed, ªIdle Air Volume Learningº will not be
carried out successfully. In this case, find the cause of the
problem by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.
ITEM SPECIFICATION
Idle speed 750±50 rpm (in ªPº or ªNº position)
Ignition timing 15ɱ5É BTDC (in ªPº or ªNº position)
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BASIC SERVICE PROCEDURE
Idle Air Volume Learning
EC-57

SEF944Y
Without CONSULT-IINBEC0642S03021. Turn ignition switch ªONº and wait at least 1 second.
2. Turn ignition switch ªOFFº and wait at least 10 seconds.
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic ªPRE-CONDITION-
INGº (previously mentioned) are in good order.
5. Turn ignition switch ªOFFº and wait at least 10 seconds.
6. Start the engine and let it idle for at least 30 seconds.
7. Disconnect throttle position sensor harness connector (brown),
then reconnect it within 5 seconds.
8. Wait 20 seconds.
9. Make sure that idle speed is within specifications. If not, the
result will be incomplete. In this case, find the cause of the
problem by referring to the NOTE below.
10. Rev up the engine two or three times. Make sure that idle
speed and ignition timing are within specifications.
ITEM SPECIFICATION
Idle speed 750±50 rpm (in ªPº or ªNº position)
Ignition timing 15ɱ5É BTDC (in ªPº or ªNº position)
NOTE:
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)Adjust closed throttle position switch and reset memory.
(Refer to Basic Inspection, EC-101.)
5)When the above four items check out OK, engine compo-
nent parts and their installation condition are question-
able. Check and eliminate the cause of the problem.
It is useful to perform ªTROUBLE DIAGNOSIS Ð SPECIFI-
CATION VALUEº, EC-136.
6)If any of the following conditions occur after the engine
has started, eliminate the cause of the problem and per-
form ªIdle air volume learningº all over again:
IEngine stalls.
IErroneous idle.
IBlown fuses related to the IACV-AAC valve system.
BASIC SERVICE PROCEDURE
Idle Air Volume Learning (Cont'd)
EC-58

SRT Set Timing=NBEC0031S0311SRT is set as ªCMPLTº 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.
Self-diagnosis resultExample
DiagnosisIgnition cycle
+ON,OFF+ON,OFF+ON,OFF+ON,
All OK Case 1 P0400 OK (1) Ð (1) OK (2) Ð (2)
P0402 OK (1) Ð (1) Ð (1) OK (2)
P1402 OK (1) OK (2) Ð (2) Ð (2)
SRT of EGR ªCMPLTº ªCMPLTº ªCMPLTº ªCMPLTº
Case 2 P0400 OK (1) Ð (1) Ð (1) Ð (1)
P0402 Ð (0) Ð (0) OK (1) Ð (1)
P1402 OK (1) OK (2) Ð (2) Ð (2)
SRT of EGR ªINCMPº ªINCMPº ªCMPLTº ªCMPLTº
NG exists Case 3 P0400 OK OK Ð Ð
P0402 Ð Ð Ð Ð
P1402 NG Ð NGNG
(Consecutive NG)
(1st trip)
DTC1st trip DTC Ð 1st trip DTCDTC
(= MIL ªONº)
SRT of EGR ªINCMPº ªINCMPº ªINCMPº ªCMPLTº
OK: Self-diagnosis is carried out and the result is OK.
NG: Self-diagnosis is carried out and the result is NG.
Ð: 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 ªCMPLTº.,Case 1 above
When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indi-
cate ªCMPLTº 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 ªCMPLTº.,Case 3 above
The table above shows that the minimum number of cycles for setting SRT as ªINCMPº is one (1) for each
self-diagnosis (Case1&2)ortwo(2)foroneofself-diagnoses (Case 3). However, in preparation for the state
emissions inspection, it is unnecessary of each self-diagnosis to be executed twice (Case 3) for the following
reasons:
IThe SRT will indicate ªCMPLTº at the time the respective self-diagnoses have one (1) OK result.
IThe emissions inspection requires ªCMPLTº of the SRT only with OK self-diagnosis results.
IWhen, during SRT driving pattern, 1st trip DTC (NG) is detected prior to ªCMPLTº of SRT, the self-diag-
nosis memory must be erased from ECM after repair.
IIf the 1st trip DTC is erased, all the SRT will indicate ªINCMPº.
NOTE:
SRT can be set as ªCMPLTº together with the DTC(s). Therefore, DTC check must always be carried out prior
to the state emission inspection even though the SRT indicates ªCMPLTº.
SRT Service ProcedureNBEC0031S0312If a vehicle has failed the state emissions inspection due to one or more SRT items indicating ªINCMPº, review
the flowchart diagnostic sequence on the next page.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-63

Items
(CONSULT-II screen terms)DTC*1 SRT codeTest value/ Test
limit
(GST only)1st trip DTC*1 Reference page
INTK TIM S/CIRC-B2 P1145 Ð Ð X EC-482
CLOSED LOOP-B1 P1148 Ð Ð X EC-491
SWL CON VC SW/CIRC P1165 Ð Ð X EC-493
CLOSED LOOP-B2 P1168 Ð Ð X EC-491
ENG OVER TEMP P1217 Ð Ð X LC-24
IGN SIGNAL-PRIMARY P1320 Ð Ð X EC-499
CPS/CIRCUIT (REF) P1335 Ð Ð X EC-510
CPS/CIRC (POS) COG P1336 Ð Ð X EC-517
EVAP VERY SMALL LEAK P1441 X X X*2 EC-526
PURG VOLUME CONT/V P1444 Ð Ð X EC-541
VENT CONTROL VALVE P1446 Ð Ð X EC-553
EVAP PURG FLOW/MON P1447 X X X*2 EC-561
VENT CONTROL VALVE P1448 Ð Ð X EC-573
FUEL LEVEL SEN/CIRC P1464 Ð Ð X EC-582
VC/V BYPASS/V P1490 Ð Ð X EC-585
VC CUT/V BYPASS/V P1491 Ð Ð X EC-591
A/T DIAG COMM LINE P1605 Ð Ð X EC-603
TP SEN/CIRC A/T P1705 Ð Ð X AT-218
P-N POS SW/CIRCUIT P1706 Ð Ð X EC-604
O/R CLTCH SOL/CIRC P1760 Ð Ð X AT-223
*1: 1st trip DTC No. is the same as DTC No.
*2: These are not displayed with GST.
NOTE:
Regarding R50 models, ª-B1º and ªBK1º indicate right bank and ª-B2º and ªBK2º indicate left bank.
HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATIONNBEC0031S06How to Erase DTC (With CONSULT-II)NBEC0031S0601NOTE:
If the DTC is not for A/T related items (see EC-8), skip steps 2 through 4.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
10 seconds and then turn it ªONº (engine stopped) again.
2. Turn CONSULT-II ªONº and touch ªA/Tº.
3. Touch ªSELF-DIAG RESULTSº.
4. Touch ªERASEº. [The DTC in the TCM (Transmission control module) will be erased.] Then touch ªBACKº
twice.
5. Touch ªENGINEº.
6. Touch ªSELF-DIAG RESULTSº.
7. Touch ªERASEº. (The DTC in the ECM will be erased.)
IIf DTCs are displayed for both ECM and TCM (Transmission control module), they need to be erased
individually from the ECM and TCM (Transmission control module).
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-72

SEF823YA
The emission related diagnostic information in the ECM can be erased by selecting ªERASEº in the ªSELF-
DIAG RESULTSº mode with CONSULT-II.
How to Erase DTC (With GST)NBEC0031S0602NOTE:
If the DTC is not for A/T related items (see EC-8), skip step 2.
1. If the ignition switch stays ªONº after repair work, be sure to turn ignition switch ªOFFº once. Wait at least
10 seconds and then turn it ªONº (engine stopped) again.
2. Perform ªSELF-DIAGNOSTIC PROCEDURE (Without CONSULT-II)º in AT section titled ªTROUBLE
DIAGNOSISº, ªSelf-diagnosisº. (The engine warm-up step can be skipped when performing the diagnosis
only to erase the DTC.)
3. Select Mode 4 with GST (Generic Scan Tool).
The emission related diagnostic information in the ECM can be erased by selecting Mode 4 with GST.
IIf the battery is disconnected, the emission-related diagnostic information will be lost after approx.
24 hours.
IThe following data are cleared when the ECM memory is erased.
1) Diagnostic trouble codes
2) 1st trip diagnostic trouble codes
3) Freeze frame data
4) 1st trip freeze frame data
5) System readiness test (SRT) codes
6) Test values
7) Others
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-73

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 Ð NATS)NBEC0031S08
SEF515Y
IIf the security indicator lights up with the ignition switch in the ªONº position or ªNATS MALFUNC-
TIONº is displayed on ªSELF-DIAG RESULTSº screen, perform self-diagnostic results mode with
CONSULT-II using NATS program card. Refer to ªIVIS (Infiniti Vehicle Immobilizer System Ð NATS)º
in EL section.
IConfirm no self-diagnostic results of IVIS (NATS) is displayed before touching ªERASEº in ªSELF-
DIAG RESULTSº mode with CONSULT-II.
IWhen replacing ECM, initialization of IVIS (NATS) system and registration of all IVIS (NATS) igni-
tion 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)
DESCRIPTIONNBEC0032
SEF217U
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned ON without the engine running. This is a bulb check.
IIf the MIL does not light up, refer to EL-114, ªWARNING LAMPSº or see EC-648.
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 FunctionNBEC0032S01The on board diagnostic system has the following two functions.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-74

Diagnostic Test
ModeKEY and ENG.
StatusFunction Explanation of Function
Mode I Ignition switch in
ªONº 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
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.
ICoolant overtemperature enrichment protection
IªMisfire (Possible three way catalyst damage)º
IªClosed loop controlº
IFail-safe mode
Diagnostic Test Mode I Ð Bulb CheckNBEC0032S03In this mode, the MIL on the instrument panel should stay ON. If it remains OFF, check the bulb. Refer to
EL-114, ªWARNING LAMPSº or see EC-648.
Diagnostic Test Mode I Ð Malfunction WarningNBEC0032S04
MIL Condition
ON When the malfunction is detected or the ECM's CPU is malfunctioning.
OFF No malfunction.
OBD System Operation ChartNBEC0033RELATIONSHIP BETWEEN MIL, 1ST TRIP DTC, DTC, AND DETECTABLE ITEMSNBEC0033S01IWhen a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are
stored in the ECM memory.
IWhen the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are
stored in the ECM memory, and the MIL will come on. For details, refer to ªTwo Trip Detection Logicº on
EC-59.
IThe MIL will go off after the vehicle is driven 3 times with no malfunction. The drive is counted only when
the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs while counting,
the counter will reset.
IThe DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A)
without the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel
Injection System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driv-
ing pattern C) without the same malfunction recurring. The ªTIMEº in ªSELF-DIAGNOSTIC RESULTSº
mode of CONSULT-II will count the number of times the vehicle is driven.
IThe 1st trip DTC is not displayed when the self-diagnosis results in ªOKº for the 2nd trip.
SUMMARY CHARTNBEC0033S02
Items Fuel Injection System Misfire Other
MIL (goes off) 3 (pattern B) 3 (pattern B) 3 (pattern B)
DTC, Freeze Frame Data (no
display)80 (pattern C) 80 (pattern C) 40 (pattern A)
1st Trip DTC (clear) 1 (pattern C), *1 1 (pattern C), *1 1 (pattern B)
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Malfunction Indicator Lamp (MIL) (Cont'd)
EC-75