2001 INFINITI QX4 heater

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
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PD
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BT
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
EC-89

DTC Inspection Priority ChartNBEC0039If some DTCs are displayed at the same time, perform inspections one by one based on the following prior-
ity chart.
Priority Detected items (DTC)
1IP0100 Mass air flow sensor
IP0110 Intake air temperature sensor
IP0115 P0125 Engine coolant temperature sensor
IP0120 Throttle position sensor
IP0180 Fuel tank temperature sensor
IP0325 Knock sensor
IP0335 P1336 Crankshaft position sensor (POS)
IP0340 Camshaft position sensor (PHASE)
IP0460 P0461 P0464 P1464 Fuel level sensor
IP0500 Vehicle speed sensor
IP0605 ECM
IP1320 Ignition signal
IP1335 Crankshaft position sensor (REF)
IP1605 A/T diagnosis communication line
IP1706 Park/Neutral position (PNP) switch
2IP0105 Absolute pressure sensor
IP0130-P0134, P0150-P0154 Heated oxygen sensor 1 (front)
IP0135 P0155 Heated oxygen sensor 1 heater (front)
IP0137-P0140, P0157-P0160 Heated oxygen sensor 2 (rear)
IP0141 P0161 Heated oxygen sensor 2 (rear) heater
IP0217 Coolant overtemperature enrichment protection
IP0443 P1444 EVAP canister purge volume control solenoid valve
IP0446 P1446 P1448 EVAP canister vent control valve
IP0450 EVAP control system pressure sensor
IP0510 Closed throttle position switch
IP0705-P0755 P1705 P1760 A/T related sensors, solenoid valves and switches
IP 1111Intake valve timing control solenoid valve
IP1140 Intake valve timing control position sensor
IP1165 Swirl control valve control vacuum check switch
IP1441 EVAP control system (VERY SMALL LEAK)
IP1447 EVAP control system purge flow monitoring
IP1490 P1491 Vacuum cut valve bypass valve
3IP0171 P0172 P0174 P0175 Fuel injection system function
IP0306 - P0300 Misfire
IP0420 P0430 Three way catalyst function
IP0440 P1440 EVAP control system (SMALL LEAK)
IP0455 EVAP control system (GROSS LEAK)
IP0505 IACV-AAC valve
IP0600 A/T communication line
IP0731-P0734 P0744 A/T function
IP1110 Intake valve timing control
IP1130 Swirl control valve control solenoid valve
IP1148 P1168 Closed loop control
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
DTC Inspection Priority Chart
EC-116

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 L/YEVAP canister purge
volume control sole-
noid valve[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
SEF994U
[Engine is running]
IEngine speed is about 2,000 rpm (More than 100
seconds after starting engine).BATTERY VOLTAGE
(11 - 14V)
SEF995U
2 R/GHeated oxygen sensor
1 (front) (bank 2)
heater[Engine is running]
IEngine speed is below 3,600 rpm.0 - 1.0V
[Engine is running]
IEngine speed is above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
3 L/ORHeated oxygen sensor
1 (front) (bank 1)
heater[Engine is running]
IEngine speed is below 3,600 rpm.0 - 1.0V
[Engine is running]
IEngine speed is above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
4 R/WHeated oxygen sensor
2 (rear) (bank 2)
heater[Engine is running]
IEngine speed is below 3,200 rpm.
IAfter driving for 2 minutes at a speed of 70 km/h
(43 MPH) or more.0 - 1.0V
[Ignition switch ªONº]
IEngine stopped
[Engine is running]
IEngine speed is above 3,200 rpm.BATTERY VOLTAGE
(11 - 14V)
5 P/BHeated oxygen sensor
2 (rear) (bank 1)
heater[Engine is running]
IEngine speed is below 3,200 rpm.
IAfter driving for 2 minutes at a speed of 70 km/h
(43 MPH) or more.0 - 1.0V
[Ignition switch ªONº]
IEngine stopped
[Engine is running]
IEngine speed is above 3,200 rpm.BATTERY VOLTAGE
(11 - 14V)
6
7
8
17PU/G
GY
Y
GY/LIACV-AAC valve[Engine is running]
IIdle speed0.1 - 14V
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-128

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
SEF300U
On Board Diagnosis LogicNBEC0097To judge the malfunction, the output from the heated oxygen sen-
sor 1 (front) is monitored to determine whether the ªrichº output is
sufficiently high and whether the ªleanº output is sufficiently low.
When both the outputs are shifting to the lean side, the malfunc-
tion will be detected.
Malfunction is detected when the maximum and minimum voltage
from the sensor are not reached to the specified voltages.
Possible CauseNBEC0433IHeated oxygen sensor 1 (front)
IHeated oxygen sensor 1 heater (front)
IFuel pressure
IInjectors
IIntake air leaks
DTC Confirmation ProcedureNBEC0098CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
IAlways perform at a temperature above þ10ÉC (14ÉF).
IBefore performing following procedure, confirm that bat-
tery voltage is more than 11V at idle.
GI
MA
EM
LC
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AT
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PD
AX
SU
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ST
RS
BT
HA
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IDX
DTC P0131, P0151 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(LEAN SHIFT MONITORING)
ECM Terminals and Reference Value (Cont'd)
EC-203

4 CHECK HEATED OXYGEN SENSOR HEATER 1 (FRONT)
1. Stop engine.
2. Check heated oxygen sensor 1 (front) harness protector color.
SEF505Y
3. Disconnect HO2S1 harness connector.
4. Check resistance between HO2S1 terminals as follows.
SEF969Y
CAUTION:
Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
OK or NG
OK (With CONSULT-II)©GO TO 5.
OK (Without CONSULT-
II)©GO TO 6.
NG©GO TO 7.
GI
MA
EM
LC
FE
AT
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PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0131, P0151 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(LEAN SHIFT MONITORING)
Diagnostic Procedure (Cont'd)
EC-207

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
SEF299U
On Board Diagnosis LogicNBEC0104To judge the malfunction, the output from the heated oxygen sen-
sor 1 (front) is monitored to determine whether the ªrichº output is
sufficiently high. The ªleanº output is sufficiently low. When both the
outputs are shifting to the rich side, the malfunction will be
detected.
Malfunction is detected when the maximum and minimum voltages
from the sensor are beyond the specified voltages.
Possible CauseNBEC0434IHeated oxygen sensor 1 (front)
IFuel pressure
IInjectors
IHeated oxygen sensor 1 heater (front)
DTC Confirmation ProcedureNBEC0105CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
IAlways perform at a temperature above þ10ÉC (14ÉF).
IBefore performing the following procedure, confirm that
battery voltage is more than 11V at idle.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0132, P0152 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RICH SHIFT MONITORING)
ECM Terminals and Reference Value (Cont'd)
EC-211

5 CHECK HEATED OXYGEN SENSOR 1 (FRONT) HEATER
Check resistance between HO2S1 terminals as follows.
SEF969Y
CAUTION:
Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
OK or NG
OK (With CONSULT-II)©GO TO 6.
OK (Without CONSULT-
II)©GO TO 7.
NG©GO TO 8.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0132, P0152 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RICH SHIFT MONITORING)
Diagnostic Procedure (Cont'd)
EC-215

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
SEF010V
On Board Diagnosis LogicNBEC0111To judge the malfunction of heated oxygen sensor 1 (front), this
diagnosis measures response time of heated oxygen sensor 1
(front) signal. The time is compensated by engine operating (speed
and load), fuel feedback control constant, and heated oxygen sen-
sor 1 (front) temperature index. Judgment is based on whether the
compensated time [heated oxygen sensor 1 (front) cycling time
index] is inordinately long or not.
Malfunction is detected when the response of the voltage signal
from the sensor takes more than the specified time.
Possible CauseNBEC0435IHarness or connectors
(The sensor circuit is open or shorted.)
IHeated oxygen sensor 1 (front)
IHeated oxygen sensor 1 heater (front)
IFuel pressure
IInjectors
IIntake air leaks
IExhaust gas leaks
IPCV valve
IMass air flow sensor
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
ECM Terminals and Reference Value (Cont'd)
EC-219