2001 INFINITI QX4 vin

EXPLANATION FOR DRIVING PATTERNS EXCEPTFOR ªMISFIRE DETERIORATION>º, ªFUEL INJECTION SYSTEMº
NBEC0033S06NBEC0033S0601
AEC574
IThe A counter will be cleared when the malfunction is detected regardless of (1) - (4).
IThe A counter will be counted up when (1) - (4) are satisfied without the same malfunction.
IThe DTC will not be displayed after the A counter reaches 40.
NBEC0033S0602Driving pattern B means the vehicle operation as follows:
All components and systems should be monitored at least once by the OBD system.
IThe B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
IThe B counter will be counted up when driving pattern B is satisfied without any malfunctions.
IThe MIL will go off when the B counter reaches 3 (*2 in ªOBD SYSTEM OPERATION CHARTº).
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
OBD System Operation Chart (Cont'd)
EC-80

Freeze frame data
item*1Description
FUEL SYS-B1*2IªFuel injection system statusº at the moment a malfunction is detected is displayed.
IOne mode in the following is displayed.
ªMODE 2º: Open loop due to detected system malfunction
ªMODE 3º: Open loop due to driving conditions (power enrichment, deceleration enrichment)
ªMODE 4º: Closed loop - using oxygen sensor(s) as feedback for fuel control
ªMODE 5º: Open loop - has not yet satisfied condition to go to closed loop FUEL SYS-B2*2
CAL/LD VALUE [%]IThe calculated load value at the moment a malfunction is detected is displayed.
COOLANT TEMP [ÉC]
or [ÉF]IThe engine coolant temperature at the moment a malfunction is detected is displayed.
S-FUEL TRIM-B1 [%]IªShort-term fuel trimº at the moment a malfunction is detected is displayed.
IThe short-term fuel trim indicates dynamic or instantaneous feedback compensation to the base fuel
schedule. S-FUEL TRIM-B2 [%]
L-FUEL TRIM-B1 [%]IªLong-term fuel trimº at the moment a malfunction is detected is displayed.
IThe long-term fuel trim indicates much more gradual feedback compensation to the base fuel schedule
than short-term fuel trim. L-FUEL TRIM-B2 [%]
ENGINE SPEED
[rpm]IThe engine speed at the moment a malfunction is detected is displayed.
VHCL SPEED [km/h]
or [mph]IThe vehicle speed at the moment a malfunction is detected is displayed.
ABSOL TH´P/S [% or
degree]IThe throttle valve opening angle at the moment a malfunction is detected is displayed.
B/FUEL SCHDL
[msec]IThe base fuel schedule at the moment a malfunction is detected is displayed.
INT/A TEMP SE [ÉC]
or [ÉF]IThe intake air temperature at the moment a malfunction is detected is displayed.
*1: The items are the same as those of 1st trip freeze frame data.
*2: Regarding R50 model, ª-B1º indicates right bank and ª-B2º indicates left bank.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-86

FUNCTIONNBEC0035S03
Diagnostic test mode Function
MODE 1 READINESS TESTSThis mode gains access to current emission-related data values, including analog
inputs and outputs, digital inputs and outputs, and system status information.
MODE 2 (FREEZE DATA)This mode gains access to emission-related data value which were stored by ECM
during the freeze frame. [For details, refer to ªFreeze Frame Dataº (EC-85).]
MODE 3 DTCsThis mode gains access to emission-related power train trouble codes which were
stored by ECM.
MODE 4 CLEAR DIAG INFOThis mode can clear all emission-related diagnostic information. This includes:
IClear number of diagnostic trouble codes (MODE 1)
IClear diagnostic trouble codes (MODE 3)
IClear trouble code for freeze frame data (MODE 1)
IClear freeze frame data (MODE 2)
IReset status of system monitoring test (MODE 1)
IClear on board monitoring test results (MODE 6 and 7)
MODE 6 (ON BOARD TESTS)This mode accesses the results of on board diagnostic monitoring tests of specific
components/systems that are not continuously monitored.
MODE 7 (ON BOARD TESTS)This mode enables the off board test drive to obtain test results for emission-related
powertrain components/systems that are continuously monitored during normal driving
conditions.
MODE 8 ÐThis mode can close EVAP system in ignition switch ªONº position (Engine stopped).
When this mode is performed, the following parts can be opened or closed.
IEVAP canister vent control valve open
IVacuum cut valve bypass valve closed
In the following conditions, this mode cannot function.
ILow ambient temperature
ILow battery voltage
IEngine running
IIgnition switch ªOFFº
ILow fuel temperature
IToo much pressure is applied to EVAP system
MODE 9 (CALIBRATION ID)This mode enables the off-board test device to request specific vehicle information
such as Vehicle Identification Number (VIN) and Calibration IDs.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Generic Scan Tool (GST) (Cont'd)
EC-96

DESCRIPTION FOR WORK FLOWNBEC0037S01
STEP DESCRIPTION
STEP IGet detailed information about the conditions and the environment when the incident/symptom occurred using
the ªDIAGNOSTIC WORK SHEETº, EC-98.
STEP IIBefore confirming the concern, check and write down (print out using CONSULT-II or GST) the (1st trip) DTC
and the (1st trip) freeze frame data, then erase the DTC and the data. (Refer to EC-72.) The (1st trip) DTC and
the (1st trip) freeze frame data can be used when duplicating the incident at STEP III & IV.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
Study the relationship between the cause, specified by (1st trip) DTC, and the symptom described by the cus-
tomer. (The ªSymptom Matrix Chartº will be useful. See EC-118.)
Also check related service bulletins for information.
STEP IIITry to confirm the symptom and under what conditions the incident occurs.
The ªDIAGNOSTIC WORK SHEETº and the freeze frame data are useful to verify the incident. Connect CON-
SULT-II to the vehicle in DATA MONITOR (AUTO TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
If the malfunction code is detected, skip STEP IV and perform STEP V.
STEP IVTry to detect the (1st trip) DTC by driving in (or performing) the ªDTC Confirmation Procedureº. Check and read
the (1st trip) DTC and (1st trip) freeze frame data by using CONSULT-II or GST.
During the (1st trip) DTC verification, be sure to connect CONSULT-II to the vehicle in DATA MONITOR (AUTO
TRIG) mode and check real time diagnosis results.
If the incident cannot be verified, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
In case the ªDTC Confirmation Procedureº is not available, perform the ªOverall Function Checkº instead. The
(1st trip) DTC cannot be displayed by this check, however, this simplified ªcheckº is an effective alternative.
The ªNGº result of the ªOverall Function Checkº is the same as the (1st trip) DTC detection.
STEP VTake the appropriate action based on the results of STEP I through IV.
If the malfunction code is indicated, proceed to TROUBLE DIAGNOSIS FOR DTC PXXXX.
If the normal code is indicated, proceed to the BASIC INSPECTION. (Refer to EC-101.) If CONSULT-II is
available, perform ªDATA MONITOR (SPEC)º mode with CONSULT-II and proceed to the ªTROUBLE DIAGNO-
SIS Ð SPECIFICATION VALUEº, EC-136. (If malfunction is detected, proceed to ªREPAIR REPLACEº.) Then
perform inspections according to the Symptom Matrix Chart. (Refer to EC-118.)
STEP VIIdentify where to begin diagnosis based on the relationship study between symptom and possible causes.
Inspect the system for mechanical binding, loose connectors or wiring damage using (tracing) ªHarness Layoutsº.
Gently shake the related connectors, components or wiring harness with CONSULT-II set in ªDATA MONITOR
(AUTO TRIG)º mode.
Check the voltage of the related ECM terminals or monitor the output data from the related sensors with CON-
SULT-II. Refer to EC-122, 127.
The ªDiagnostic Procedureº in EC section contains a description based on open circuit inspection. A short circuit
inspection is also required for the circuit check in the Diagnostic Procedure. For details, refer to GI-27, ªCircuit
Inspectionº.
Repair or replace the malfunction parts.
If malfunctioning part cannot be detected, perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº,
EC-140.
STEP VIIOnce you have repaired the circuit or replaced a component, you need to run the engine in the same conditions
and circumstances which resulted in the customer's initial complaint.
Perform the ªDTC Confirmation Procedureº and confirm the normal code [DTC No. P0000] is detected. If the
incident is still detected in the final check, perform STEP VI by using a different method from the previous one.
Before returning the vehicle to the customer, be sure to erase the unnecessary (already fixed) (1st trip) DTC in
ECM and TCM (Transmission control module). (Refer to EC-72.)
TROUBLE DIAGNOSIS Ð INTRODUCTION
Work Flow (Cont'd)
EC-100

9 CHECK THROTTLE VALVE OPERATION
1. Remove intake air ducts.
2. Check throttle valve operation when moving throttle drum by hand.
OK or NG
OK©1. Retighten the throttle drum fixing nuts.
2. GO TO 7.
NG©1. Clean the throttle body and throttle valve.
2. GO TO 7.
10 CHECK THROTTLE POSITION SWITCH CLOSED POSITION-I
NOTE:
Always check ignition timing before performing the following.
1. Warm up engine to normal operating temperature.
2. Stop engine.
3. Remove the vacuum hose connected to the throttle opener.
4. Connect suitable vacuum hose to vacuum pump as shown below.
SEF793WA
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum is free from the throttle opener
rod.
With CONSULT-II©GO TO 11.
Without CONSULT-II©GO TO 15.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection (Cont'd)
EC-104

Fail-safe Chart=NBEC0040The ECM enters fail-safe mode, if any of the following malfunctions is detected due to the open or short cir-
cuit. When the ECM enters the fail-safe mode, the MIL illuminates.
DTC No. Detected items Engine operating condition in fail-safe mode
P0100 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0115 Engine coolant temperature
sensor circuitEngine coolant temperature will be determined by ECM based on the time after
turning ignition switch ªONº or ªSTARTº.
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 Start40ÉC (104ÉF)
More than approx. 4 minutes
after ignition ON or Start80ÉC (176ÉF)
Except as shown above40 - 80ÉC (104 - 176ÉF)
(Depends on the time)
P0120 Throttle position sensor cir-
cuitThrottle position will be determined based on the injected fuel amount and the
engine speed.
Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
P1335 Crankshaft position sensor
(REF) circuitCompression TDC signal (120É signal) is controlled by camshaft position sensor
(PHASE) signal and crankshaft position sensor (POS) signal. Ignition timing will be
delayed 0É to 2É.
Unable to
access ECMECMECM fail-safe activating condition
The computing function of the ECM was judged to be malfunctioning.
When the fail-safe system activates (i.e., if the ECM detects a malfunction condi-
tion in the CPU of ECM), the MIL on the instrument panel lights to warn the driver.
However it is not possible to access ECM and DTC cannot be confirmed.
Engine control with fail-safe
When ECM fail-safe is operating, fuel injection, ignition timing, fuel pump operation,
IACV-AAC valve operation and cooling fan operation are controlled under certain
limitations.
ECM fail-safe operation
Engine speedEngine speed will not rise more than 3,000
rpm
Fuel injection Simultaneous multiport fuel injection system
Ignition timing Ignition timing is fixed at the preset valve
Fuel pumpFuel pump relay is ªONº when engine is running
and ªOFFº when engine stalls
IACV-AAC valve Full open
Replace ECM, if ECM fail-safe condition is confirmed.
GI
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PD
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Fail-safe Chart
EC-117

MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/VIIgnition switch: ON OFF
HO2S1 HTR (B1)
HO2S1 HTR (B2)IEngine speed: Below 3,600 rpm ON
IEngine speed: Above 3,600 rpm OFF
HO2S2 HTR (B1)
HO2S2 HTR (B2)IIgnition switch: ON (Engine stopped)
IEngine speed: Above 3,200 rpmOFF
IEngine speed: Below 3,200 rpm [After driving for 2 minutes at a speed
of 70 km/h (43 MPH) or more]ON
VC/V BYPASS/V Ignition switch: ON OFF
CAL/LD VALUEIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 14.0 - 33.0%
2,500 rpm 12.0 - 25.0%
ABSOL TH´P/SIEngine: After warming up Throttle valve: fully closed 0.0%
IEngine: After warming up
IIgnition switch: ON
(Engine stopped)Throttle valve: fully opened Approx. 80%
MASS AIRFLOWIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 2.0 - 6.0 g´m/s
2,500 rpm 7.0 - 20.0 g´m/s
ABSOL PRES/SEIIgnition switch: ON Approx. 4.4V
SWRL CONT S/VIEngine speed: IdleEngine coolant temperature is
between 15ÉC (59ÉF) to 50ÉC
(122ÉF).ON
Engine coolant temperature is above
55ÉC (131ÉF).OFF
SWL CON VC SWIEngine speed: Idle
IEngine coolant temperature is between 15ÉC (59ÉF) to 50ÉC (122ÉF).OFF
IEngine speed: Idle
IEngine coolant temperature is above 55ÉC (131ÉF).ON
INT/V TIM (B1)
INT/V TIM (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0É CA
2,000 rpm Approximately 12 - 18É CA
INT/V SOL (B1)
INT/V SOL (B2)IEngine: After warming up
IShift lever ªNº
IQuickly depressed accelerator
pedal
INo-loadIdle 0%
2,000 rpm Approximately 40%
Major Sensor Reference Graph in Data Monitor
Mode
NBEC0043The following are the major sensor reference graphs in ªDATA MONITORº mode.
THRTL POS SEN, ABSOL TH´P/S, CLSD THL POSNBEC0043S01Below is the data for ªTHRTL POS SENº, ªABSOL TH´P/Sº and ªCLSD THL POSº when depressing the accel-
erator pedal with the ignition switch ªONº.
The signal of ªTHRTL POS SENº and ªABSOL TH´P/Sº should rise gradually without any intermittent drop or
rise after ªCLSD THL POSº is changed from ªONº to ªOFFº.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
CONSULT-II Reference Value in Data Monitor Mode (Cont'd)
EC-124

SEF306Y
ENG SPEED, MAS A/F SE-B1, THRTL POS SEN, HO2S2 (B1), HO2S1 (B1), INJ PULSE-B1NBEC0043S02Below is the data for ªENG SPEEDº, ªMAS A/F SE-B1º, ªTHRTL POS SENº, ªHO2S2 (B1)º, ªHO2S1 (B1)º and
ªINJ PULSE-B1º when revving engine quickly up to 4,800 rpm under no load after warming up engine suffi-
ciently.
Each value is for reference, the exact value may vary.
SEF241Y
GI
MA
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LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Major Sensor Reference Graph in Data Monitor Mode (Cont'd)
EC-125