IDX INFINITI QX4 2001 Factory Service Manual

21 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 2) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (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 (B2)º in ªDATA MONITORº mode.
6. Running 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 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 62 and ground.
6. Make sure that the 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 (With CONSULT-II)©GO TO 23.
OK (Without CONSULT-
II)©GO TO 24.
NG©GO TO 22.
22 DETECT MALFUNCTIONING PART
Check the following.
1. Check fuel pressure regulator. Refer to EC-40.
2. Check mass air flow sensor and its circuit. Refer to EC-150.
3. Check injector and its circuit. Refer to EC-616.
Clean or replace if necessary.
4. Check engine coolant temperature sensor and its circuit. Refer to EC-187.
5. Check 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.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-51

25 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
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)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).
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 and ground.
6. Make sure that the 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©INSPECTION END
NG©GO TO 26.
26 DETECT MALFUNCTIONING PART
Check the following.
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.
27 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 1) harness connector.
4. Check harness continuity between ECM terminal 63 and heated oxygen sensor 1 (front) RH harness connector terminal
1.
Refer to Wiring Diagram, EC-196.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-53

31 CHECK ªCOº %
With CONSULT-II
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
SEF976U
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
SEF978U
3. Check ªCOº %.
Idle CO: 1.0 - 9.5%
Without CONSULT-II
1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
SEF976U
2. Rev engine (2,000 to 3,000 rpm) two or three times under no-load, then run engine at idle speed.
SEF978U
3. Check ªCOº %.
4. After checking CO%,
a. Disconnect the resistor from terminals of engine coolant temperature sensor.
b. Connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
OK or NG
OK©GO TO 32.
NG©GO TO 33.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-55

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

IntroductionNBEC0029The 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:
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
The above information can be checked using procedures listed in the table below.
X: Applicable Ð: Not applicable
DTC 1st trip DTCFreeze Frame
data1st trip Freeze
Frame dataSRT code Test value
CONSULT-II X X X X X Ð
GST X X*1 X Ð X X
*1: 1st trip DTCs for self-diagnoses concerning SRT items cannot be shown on the GST display.
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-117.)
Two Trip Detection LogicNBEC0030When 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 ªtripº in the ªTwo Trip Detection Logicº 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.
X: Applicable Ð: Not Exit
ItemsMIL DTC 1st trip DTC
1st trip 2nd trip
1st trip
displaying2nd trip
displaying1st trip
displaying2nd trip
displaying
BlinkingLighting
upBlinkingLighting
up
Misfire (Possible three way cata-
lyst damage) Ð DTC: P0300 -
P0306 (0701, 0605 Ð 0608) is
being detectedX ÐÐÐÐÐ X Ð
Misfire (Possible three way cata-
lyst damage) Ð DTC: P0300 -
P0306 (0701, 0605 Ð 0608) is
being detectedÐÐ X ÐÐ X ÐÐ
Closed loop control
Ð DTC: P1148 (0307), P1168
(0308)ÐXÐÐXÐXÐ
Fail-safe items (Refer to EC-117.) Ð X Ð Ð X*1 Ð X*1 Ð
Except above Ð Ð Ð X Ð X X Ð
*1: Except ªECMº
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Introduction
EC-59

The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-II or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
details, see EC-85.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no prior-
ity for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
Priority Items
1Freeze frame data Misfire Ð DTC: P0300 - P0306
Fuel Injection System Function Ð DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
For example, the EGR malfunction (Priority: 2) was detected and the freeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st trip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or
1st trip freeze frame data can be stored in the ECM). If freeze frame data is stored in the ECM memory and
freeze frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged
in the ECM memory.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM
memory is erased. Procedures for clearing the ECM memory are described in ªHOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATIONº, EC-72.
SYSTEM READINESS TEST (SRT) CODENBEC0031S03System Readiness Test (SRT) code is specified in Mode 1 of SAE J1979.
As part of an enhanced emissions test for Inspection & Maintenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has completed self-diagnosis of major emission systems and com-
ponents. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspection due to one or more SRT items indicating ªINCMPº,
use the information in this Service Manual to set the SRT to ªCMPLTº.
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate ªCMPLTº for each application system. Once set as ªCMPLTº, the SRT status remains
ªCMPLTº until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate ªINCMPº for these items.
NOTE:
The SRT will also indicate ªINCMPº if the self-diagnosis memory is erased for any reason or if the ECM
memory power supply is interrupted for several hours.
If, during the state emissions inspection, the SRT indicates ªCMPLTº for all test items, the inspector will con-
tinue with the emissions test. However, if the SRT indicates ªINCMPº for one or more of the SRT items the
vehicle is returned to the customer untested.
NOTE:
If MIL is ªONº during the state emissions inspection, the vehicle is also returned to the customer untested even
though the SRT indicates ªCMPLTº for all test items. Therefore, it is important to check SRT (ªCMPLTº) and
DTC (No DTCs) before the inspection.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-61

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

SEF949Z
How to Set SRT CodeNBEC0031S0302To set all SRT codes, self-diagnosis for the items indicated above must be performed one or more times. Each
diagnosis may require a long period of actual driving under various conditions.
With CONSULT-II
Perform corresponding DTC Confirmation Procedure one by one based on ªPerformance Priorityº in the table
on EC-62.
Without CONSULT-II
The most efficient driving pattern in which SRT codes can be properly set is explained on the next page. The
driving pattern should be performed one or more times to set all SRT codes.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-65

IThe time required for each diagnosis varies with road surface conditions, weather, altitude, individual driv-
ing habits, etc.
Zone A refers to the range where the time required, for the diagnosis under normal conditions*, is the
shortest.
Zone B refers to the range where the diagnosis can still be performed if the diagnosis is not completed
within zone A.
*: Normal conditions refer to the following:
þ Sea level
þ Flat road
þ Ambient air temperature: 20 - 30ÉC (68 - 86ÉF)
þ Diagnosis is performed as quickly as possible under normal conditions.
Under different conditions [For example: ambient air temperature other than 20 - 30ÉC (68 - 86ÉF)], diag-
nosis may also be performed.
Pattern 1:
IThe engine is started at the engine coolant temperature of þ10 to 35ÉC (14 to 95ÉF)
(where the voltage between the ECM terminal 70 and ground is 3.0 - 4.3V).
IThe engine must be operated at idle speed until the engine coolant temperature is greater than 70ÉC
(158ÉF) (where the voltage between the ECM terminal 70 and ground is lower than 1.4V).
IThe engine is started at the fuel tank temperature of warmer than 0ÉC (32ÉF) (where the voltage
between the ECM terminal 92 and ground is less than 4.1V).
Pattern 2:
IWhen steady-state driving is performed again even after it is interrupted, each diagnosis can be conducted.
In this case, the time required for diagnosis may be extended.
Pattern 3:
IThe driving pattern outlined in *2 must be repeated at least 3 times.
Pattern 4:
ITests are performed after the engine has been operated for at least 17 minutes.
IThe accelerator pedal must be held very steady during steady-state driving.
IIf the accelerator pedal is moved, the test must be conducted all over again.
*1: Depress the accelerator pedal until vehicle speed is 90 km/h (56 MPH), then release the accelerator pedal
and keep it released for more than 10 seconds. Depress the accelerator pedal until vehicle speed is 90 km/h
(56 MPH) again.
*2: Operate the vehicle in the following driving pattern.
1) Decelerate vehicle to 0 km/h (0 MPH) and let engine idle.
2) Repeat driving pattern shown below at least 10 times.
IDuring acceleration, hold the accelerator pedal as steady as possible.
SEF414S
*3: Checking the vehicle speed with GST is advised.
Suggested Transmission Gear Position for A/T Models
Set the selector lever in the ªDº position with the overdrive switch turned ON.
Suggested upshift speeds for M/T models
Shown below are suggested vehicle speeds for shifting into a higher gear. These suggestions relate to fuel
economy and vehicle performance. Actual upshift speeds will vary according to road conditions, the weather
and individual driving habits.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-67

SRT item Self-diagnostic test itemTest value (GST display)
Test limit Application
TID CID
O2 SENSORHeated oxygen sensor 1 (front)
(bank 1)09H 04H Max. X
0AH 84H Min. X
0BH 04H Max. X
0CH 04H Max. X
0DH 04H Max. X
Heated oxygen sensor 1 (front)
(bank 2)11H 05H Max. X
12H 85H Min. X
13H 05H Max. X
14H 05H Max. X
15H 05H Max. X
Heated oxygen sensor 2 (rear)
(bank 1)19H 86H Min. X
1AH 86H Min. X
1BH 06H Max. X
1CH 06H Max. X
Heated oxygen sensor 2 (rear)
(bank 2)21H 87H Min. X
22H 87H Min. X
23H 07H Max. X
24H 07H Max. X
O2 SENSOR HEATERHeated oxygen sensor 1 (front) heater
(bank 1)29H 08H Max. X
2AH 88H Min. X
Heated oxygen sensor 1 (front) heater
(bank 2)2BH 09H Max. X
2CH 89H Min. X
Heated oxygen sensor 2 (rear) heater
(bank 1)2DH 0AH Max. X
2EH 8AH Min. X
Heated oxygen sensor 2 (rear) heater
(bank 2)2FH 0BH Max. X
30H 8BH Min. X
EMISSION-RELATED DIAGNOSTIC INFORMATION ITEMSNBEC0031S05X: Applicable Ð: Not applicable
Items
(CONSULT-II screen terms)DTC*1 SRT codeTest value/ Test
limit
(GST only)1st trip DTC*1 Reference page
NO DTC IS DETECTED.
FURTHER TESTING
MAY BE REQUIRED.P0000ÐÐÐÐ
MAF SEN/CIRCUIT P0100 Ð Ð X EC-150
ABSL PRES SEN/CIRC P0105 Ð Ð X EC-158
AIR TEMP SEN/CIRC P0110 Ð Ð X EC-164
COOLANT T SEN/CIRC P0115 Ð Ð X EC-169
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Emission-related Diagnostic Information (Cont'd)
EC-69