2001 INFINITI QX4 Engine control

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

DATA MONITOR MODE=NBEC0034S06
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]qqIIndicates the engine speed computed
from the REF signal (120É signal) of the
crankshaft position sensor (REF).
CKPS´RPM (POS)
[rpm]qIIndicates the engine speed computed
from the POS signal (1É signal) of the
crankshaft position sensor (POS).IAccuracy becomes poor if engine
speed drops below the idle rpm.
IIf the signal is interrupted while the
engine is running, an abnormal value
may be indicated.
POS COUNTqIIndicates the number of signal plate
(Flywheel/Drive Plate) cogs (tooth) dur-
ing one revolution of the engine.
MAS A/F SE-B1 [V]qqIThe signal voltage of the mass air flow
sensor is displayed.IWhen the engine is stopped, a certain
value is indicated.
COOLAN TEMP/S
[ÉC] or [ÉF]qqIThe engine coolant temperature (deter-
mined by the signal voltage of the
engine coolant temperature sensor) is
displayed.IWhen the engine coolant temperature
sensor is open or short-circuited, ECM
enters fail-safe mode. The engine cool-
ant temperature determined by the
ECM is displayed.
HO2S1 (B1) [V]qq
IThe signal voltage of the front heated
oxygen sensor is displayed.
HO2S1 (B2) [V]qq
HO2S2 (B1) [V]qq
IThe signal voltage of the rear heated
oxygen sensor is displayed.
HO2S2 (B2) [V]qq
HO2S1 MNTR (B1)
[RICH/LEAN]qIDisplay of front heated oxygen sensor
signal during air-fuel ratio feedback
control:
RICH ... means the mixture became
ªrichº, and control is being affected
toward a leaner mixture.
LEAN ... means the mixture became
ªleanº, and control is being affected
toward a rich mixture.IAfter turning ON the ignition switch,
ªRICHº is displayed until air-fuel mixture
ratio feedback control begins.
IWhen the air-fuel ratio feedback is
clamped, the value just before the
clamping is displayed continuously. HO2S1 MNTR (B2)
[RICH/LEAN]q
HO2S2 MNTR (B1)
[RICH/LEAN]qIDisplay of rear heated oxygen sensor
signal:
RICH ... means the amount of oxygen
after three way catalyst is relatively
small.
LEAN ... means the amount of oxygen
after three way catalyst is relatively
large.IWhen the engine is stopped, a certain
value is indicated.
HO2S2 MNTR (B2)
[RICH/LEAN]q
VHCL SPEED SE
[km/h] or [mph]qqIThe vehicle speed computed from the
vehicle speed sensor signal is dis-
played.
BATTERY VOLT [V]qqIThe power supply voltage of ECM is
displayed.
THRTL POS SEN [V]qqIThe throttle position sensor signal volt-
age is displayed.
FUEL T/TMP SE
[ÉC] or [ÉF]IThe fuel temperature judged from the
tank fuel temperature sensor signal
voltage is displayed.GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
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IDX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-87

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
INT/A TEMP SE
[ÉC] or [ÉF]qqIThe intake air temperature determined
by the signal voltage of the intake air
temperature sensor is indicated.
EVAP SYS PRES [V]qIThe signal voltage of EVAP control sys-
tem pressure sensor is displayed.
ABSOL PRES/SE [V]qIThe signal voltage of the absolute pres-
sure sensor is displayed.
FUEL LEVEL SE [V]qIThe signal voltage of the fuel level sen-
sor is displayed.
START SIGNAL
[ON/OFF]qqIIndicates [ON/OFF] condition from the
starter signal.IAfter starting the engine, [OFF] is dis-
played regardless of the starter signal.
CLSD THL POS
[ON/OFF]qqIIndicates idle position [ON/OFF] com-
puted by ECM according to the throttle
position sensor signal.
CLSD THL/P SW
[ON/OFF]qIIndicates mechanical contact [ON/OFF]
condition of the closed throttle position
switch.
AIR COND SIG
[ON/OFF]qqIIndicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
P/N POSI SW
[ON/OFF]qqIIndicates [ON/OFF] condition from the
park/neutral position (PNP) switch sig-
nal.
PW/ST SIGNAL
[ON/OFF]qqI[ON/OFF] condition of the power steer-
ing oil pressure switch determined by
the power steering oil pressure signal is
indicated.
LOAD SIGNAL
[ON/OFF]qqIIndicates [ON/OFF] condition from the
electrical load signal and/or lighting
switch.
ON ... rear defogger is operating and/or
lighting switch is on.
OFF ... rear defogger is not operating
and lighting switch is not on.
IGNITION SW
[ON/OFF]qIIndicates [ON/OFF] condition from igni-
tion switch.
SWRL CONT S/V
[ON/OFF]qIThe control condition of the swirl con-
trol valve control solenoid valve (deter-
mined by ECM according to the input
signals) is indicated.
ION ... Swirl control valve is closed.
OFF ... Swirl control valve is opened.
INJ PULSE-B1
[msec]q
IIndicates the actual fuel injection pulse
width compensated by ECM according
to the input signals.IWhen the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
B/FUEL SCHDL
[msec]qIªBase fuel scheduleº indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board
correction.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-88

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
IGN TIMING [BTDC]qIIndicates the ignition timing computed
by ECM according to the input signals.IWhen the engine is stopped, a certain
value is indicated.
IACV-AAC/V [step]qIIndicates the IACV-AAC valve control
value computed by ECM according to
the input signals.
PURG VOL C/V [%]IIndicates the EVAP canister purge vol-
ume control solenoid valve control
value computed by the ECM according
to the input signals.
IThe opening becomes larger as the
value increases.
A/F ALPHA-B1 [%]q
IThe mean value of the air-fuel ratio
feedback correction factor per cycle is
indicated.IWhen the engine is stopped, a certain
value is indicated.
IThis data also includes the data for the
air-fuel ratio learning control. A/F ALPHA-B2 [%]q
AIR COND RLY
[ON/OFF]qIThe air conditioner relay control condi-
tion (determined by ECM according to
the input signal) is indicated.
FUEL PUMP RLY
[ON/OFF]qIIndicates the fuel pump relay control
condition determined by ECM accord-
ing to the input signals.
VENT CONT/V
[ON/OFF]IThe control condition of the EVAP can-
ister vent control valve (determined by
ECM according to the input signal) is
indicated.
ION ... Closed
OFF ... Open
HO2S1 HTR (B1)
[ON/OFF]IIndicates [ON/OFF] condition of front
heated oxygen sensor heater deter-
mined by ECM according to the input
signals. HO2S1 HTR (B2)
[ON/OFF]
HO2S2 HTR (B1)
[ON/OFF]IIndicates [ON/OFF] condition of rear
heated oxygen sensor heater deter-
mined by ECM according to the input
signals. HO2S2 HTR (B2)
[ON/OFF]
VC/V BYPASS/V
[ON/OFF]IThe control condition of the vacuum cut
valve bypass valve (determined by
ECM according to the input signal) is
indicated.
ION ... Open
OFF ... Closed
CAL/LD VALUE [%]IªCalculated load valueº indicates the
value of the current airflow divided by
peak airflow.
ABSOL TH´P/S [%]IªAbsolute throttle position sensorº indi-
cates the throttle opening computed by
ECM according to the signal voltage of
the throttle position sensor.
MASS AIRFLOW
[g´m/s]IIndicates the mass airflow computed by
ECM according to the signal voltage of
the mass airflow sensor.GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-89

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
INT/V TIM (B1) [ÉCA]
IIndicate [ÉCA] of intake camshaft
advanced angle.
INT/V TIM (B2) [ÉCA]
INT/V SOL (B1) [%]IThe control condition of the intake
valve timing control solenoid valve is
indicated. INT/V SOL (B2) [%]
TRVL AFTER MIL
[km] or [Mile]IDistance traveled while MIL is activated
VIAS S/V
[ON/OFF]IThe control condition of the VIAS con-
trol solenoid valve (determined by ECM
according to the input signal) is indi-
cated.
IOFF ... VIAS control solenoid valve is
not operating.
ON ... VIAS control solenoid valve is
operating.
SWL CON VC SWIIndicates [ON/OFF] condition from the
swirl control valve control vacuum
check switch.
ON ... Swirl control valve is not opera-
tional.
OFF ... Swirl control valve is opera-
tional.
IDL A/V LEANIDisplay the condition of idle air volume
learning
YET ... Idle air volume learning has not
been performed yet.
CMPLT ... Idle air volume learning has
already been performed successfully.
INCMP ... Idle air volume learning has
not been performed successfully.
Voltage [V]IVoltage measured by the voltage
probe.
Frequency
[msec] or [Hz] or [%]IPulse width, frequency or duty cycle
measured by the pulse probe.IOnly ª#º is displayed if item is unable to
be measured.
IFigures with ª#ºs are temporary ones.
They are the same figures as an actual
piece of data which was just previously
measured.
NOTE:
IAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
IRegarding R50 model, ª-B1º indicates right bank and ª-B2º indicates left bank.
IBank 1 (-B1 or BK1) includes No. 1 cylinder.
DATA MONITOR (SPEC) MODENBEC0034S11
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
MAS A/F SE-B1 [V]qqIThe signal voltage of the mass air flow sen-
sor specification is displayed.IWhen the engine is running, specifi-
cation range is indicated.
B/FUEL SCHDL
[msec]IªBase fuel scheduleº indicates the fuel injec-
tion pulse width programmed into ECM,
prior to any learned on board correction.IWhen the engine is running, specifi-
cation range is indicated.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-90

Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
A/F ALPHA-B1 [%]q
IIndicates the mean value of the air-fuel ratio
feedback correction factor per cycle.IWhen the engine is running, specifi-
cation range is indicated.
IThis data also includes the data for
the air-fuel ratio learning control. A/F ALPHA-B2 [%]q
NOTE:
IAny monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
IRegarding R50 model, ªB1º indicates bank 1 and ªB2º indicates bank 2.
ACTIVE TEST MODENBEC0034S07
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJECTIONIEngine: Return to the original
trouble condition
IChange the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IFuel injectors
IHeated oxygen sensor
IGNITION TIMINGIEngine: Return to the original
trouble condition
ITiming light: Set
IRetard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IAdjust initial ignition timing
IACV-AAC/V
OPENINGIEngine: After warming up, idle
the engine.
IChange the IACV-AAC valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
IIACV-AAC valve
POWER BAL-
ANCEIEngine: After warming up, idle
the engine.
IA/C switch ªOFFº
IShift lever ªNº
ICut off each injector signal one
at a time using CONSULT-II.Engine runs rough or dies.IHarness and connector
ICompression
IInjectors
IPower transistor
ISpark plugs
IIgnition coils
ENG COOLANT
TEMPIEngine: Return to the original
trouble condition
IChange the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IEngine coolant temperature sen-
sor
IFuel injectors
FUEL PUMP
RELAYIIgnition switch: ON
(Engine stopped)
ITurn the fuel pump relay ªONº
and ªOFFº using CONSULT-II
and listen to operating sound.Fuel pump relay makes the operat-
ing sound.IHarness and connector
IFuel pump relay
VIAS SOL VALVEIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
SWIRL CONT
S O L VA LV EIIgnition switch: ON
ITurn solenoid valve ªONº and
ªOFFº with CONSULT-II and lis-
ten for operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
PURG VOL
CONT/VIEngine: After warming up, run
engine at 1,500 rpm.
IChange the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-II.Engine speed changes according
to the opening percent.IHarness and connector
ISolenoid valve
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-91

TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL/T TEMP
SENIChange the fuel tank temperature using CONSULT-II.
VENT
CONTROL/VIIgnition switch: ON
(Engine stopped)
ITurn solenoid valve ªONº and
ªOFFº with the CONSULT-II and
listen to operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
VC/V BYPASS/VIIgnition switch: ON
(Engine stopped)
ITurn solenoid valve ªONº and
ªOFFº with the CONSULT-II and
listen to operating sound.Solenoid valve makes an operating
sound.IHarness and connector
ISolenoid valve
TARGET INT/V
TIMIEngine: After warming up, hold
engine speed at 1,500 to 2,000
rpm.
IChange the intake valve timing
using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.IHarness and connector
IIntake valve timing control sole-
noid valve
DTC & SRT CONFIRMATION MODENBEC0034S08SRT STATUS ModeNBEC0034S0801For details, refer to ªSYSTEM READINESS TEST (SRT) CODEº,
EC-61.
SRT Work Support ModeNBEC0034S0803This mode enables a technician to drive a vehicle to set the SRT
while monitoring the SRT status.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-92

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