2001 INFINITI QX4 vin

SEF327R
Component DescriptionNBEC0130The heated oxygen sensor 2 (rear), after three way catalyst, moni-
tors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1
(front) are shifted, the air fuel ratio is controlled to stoichiometric,
by the signal from the heated oxygen sensor 2 (rear).
This sensor is made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions.
Under normal conditions the heated oxygen sensor 2 (rear) is not
used for engine control operation.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0131Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
IEngine: After warming upRevving engine from idle up to
2,000 rpm0 - 0.3V+,Approx. 0.6 - 1.0V
HO2S2 MNTR
(B1)
HO2S2 MNTR
(B2)LEAN+,RICH
ECM Terminals and Reference ValueNBEC0658Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
72 ORHeated oxygen sensor
2 (rear) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
71 OR/LHeated oxygen sensor
2 (rear) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
SEF304UB
On Board Diagnosis LogicNBEC0133The heated oxygen sensor 2 (rear) has a much longer switching
time between rich and lean than the heated oxygen sensor 1
(front). The oxygen storage capacity before the three way catalyst
causes the longer switching time. To judge the malfunctions of
heated oxygen sensor 2 (rear), ECM monitors whether the mini-
mum voltage of sensor is sufficiently low during the various driving
condition such as fuel-cut.
Malfunction is detected when the minimum voltage from the sen-
sor is not reached to the specified voltage.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0137, P0157 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(MIN. VOLTAGE MONITORING)
Component Description
EC-247

SEF327R
Component DescriptionNBEC0138The heated oxygen sensor 2 (rear), after three way catalyst, moni-
tors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1
(front) are shifted, the air fuel ratio is controlled to stoichiometric,
by the signal from the heated oxygen sensor 2 (rear).
This sensor is made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions.
Under normal conditions the heated oxygen sensor 2 (rear) is not
used for engine control operation.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0139Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
IEngine: After warming upRevving engine from idle up to
2,000 rpm0 - 0.3V+,Approx. 0.6 - 1.0V
HO2S2 MNTR
(B1)
HO2S2 MNTR
(B2)LEAN+,RICH
ECM Terminals and Reference ValueNBEC0659Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
72 ORHeated oxygen sensor
2 (rear) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
71 OR/LHeated oxygen sensor
2 (rear) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
SEF303UB
On Board Diagnosis LogicNBEC0141The heated oxygen sensor 2 (rear) has a much longer switching
time between rich and lean than the heated oxygen sensor 1
(front). The oxygen storage capacity before the three way catalyst
causes the longer switching time. To judge the malfunctions of
heated oxygen sensor 2 (rear), ECM monitors whether the maxi-
mum voltage of the sensor is sufficiently high during the various
driving condition such as fuel-cut.
Malfunction is detected when the maximum voltage from the sen-
sor is not reached to the specified voltage.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0138, P0158 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(MAX. VOLTAGE MONITORING)
Component Description
EC-257

6 CHECK HEATED OXYGEN SENSOR 2 (REAR)-I
Without CONSULT
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Set voltmeter probes between ECM terminal 72 (HO2S2 bank 1 right signal) or 71 (HO2S bank 2 left signal) and
engine ground.
4. Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
SEF313XA
OK or NG
OK©GO TO 9.
NG©GO TO 7.
7 CHECK HEATED OXYGEN SENSOR 2 (REAR)-II
Idle vehicle for 10 minutes, then check voltage between the same terminals as in Test No. 6; or check voltage when coast-
ing from 80 km/h (50 MPH) in ªDº position with ªODº OFF.
The voltage should go below 0.57V at least once during this procedure.
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©GO TO 9.
NG©GO TO 8.
8 REPLACE HEATED OXYGEN SENSOR 2 (REAR)
1. Stop vehicle and turn ignition switch ªOFFº.
2. Check heated oxygen sensor 2 (rear) harness protector color.
SEF372Z
CAUTION:
Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool
J-43897-18 or J-43897-12 and approved anti-seize lubricant.
©Replace malfunctioning heated oxygen sensor 2 (rear).
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0138, P0158 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(MAX. VOLTAGE MONITORING)
Diagnostic Procedure (Cont'd)
EC-265

SEF327R
Component DescriptionNBEC0146The heated oxygen sensor 2 (rear), after three way catalyst, moni-
tors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1
(front) are shifted, the air fuel ratio is controlled to stoichiometric,
by the signal from the heated oxygen sensor 2 (rear).
This sensor is made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions.
Under normal conditions the heated oxygen sensor 2 (rear) is not
used for engine control operation.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0147Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
IEngine: After warming upRevving engine from idle up to
2,000 rpm0 - 0.3V+,Approx. 0.6 - 1.0V
HO2S2 MNTR
(B1)
HO2S2 MNTR
(B2)LEAN+,RICH
ECM Terminals and Reference ValueNBEC0660Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
72 ORHeated oxygen sensor
2 (rear) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
71 OR/LHeated oxygen sensor
2 (rear) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
SEF302U
On Board Diagnosis LogicNBEC0149The heated oxygen sensor 2 (rear) has a much longer switching
time between rich and lean than the heated oxygen sensor 1
(front). The oxygen storage capacity before the three way catalyst
causes the longer switching time. To judge the malfunctions of
heated oxygen sensor 2 (rear), ECM monitors whether the switch-
ing response of the sensor's voltage is faster than specified during
the various driving condition such as fuel-cut.
Malfunction is detected when it takes more time for the sensor to
respond between rich and lean than the specified time.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0139, P0159 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Component Description
EC-267

6 CHECK REAR HEATED OXYGEN SENSOR 2 (REAR)-I
Without CONSULT-II
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Set voltmeter probes between ECM terminal 72 (HO2S2 bank 1 right signal) or 71 (HO2S2 bank 2 left signal) and
engine ground.
4. Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
SEF313XA
OK or NG
OK©GO TO 9.
NG©GO TO 7.
7 CHECK REAR HEATED OXYGEN SENSOR 2 (REAR)-II
Idle vehicle for 10 minutes, then check voltage between the same terminals as in Test No. 6; or check voltage when coast-
ing from 80 km/h (50 MPH) in ªDº position with ªODº OFF.
The voltage should go below 0.57V at least once during this procedure.
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©GO TO 9.
NG©GO TO 8.
8 REPLACE REAR HEATED OXYGEN SENSOR
1. Stop vehicle and turn ignition switch ªOFFº.
2. Check heated oxygen sensor 2 (rear) harness protector color.
SEF372Z
CAUTION:
Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool
J-43897-18 or J-43897-12 and approved anti-seize lubricant.
©Replace malfunctioning heated oxygen sensor 2 (rear).
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0139, P0159 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-275

SEF327R
Component DescriptionNBEC0154The heated oxygen sensor 2 (rear), after three way catalyst, moni-
tors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the heated oxygen sensor 1
(front) are shifted, the air fuel ratio is controlled to stoichiometric,
by the signal from the heated oxygen sensor 2 (rear).
This sensor is made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions.
Under normal conditions the heated oxygen sensor 2 (rear) is not
used for engine control operation.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0155Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
IEngine: After warming upRevving engine from idle up to
2,000 rpm0 - 0.3V+,Approx. 0.6 - 1.0V
HO2S2 MNTR
(B1)
HO2S2 MNTR
(B2)LEAN+,RICH
ECM Terminals and Reference ValueNBEC0661Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
72 ORHeated oxygen sensor
2 (rear) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
71 OR/LHeated oxygen sensor
2 (rear) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V
SEF305UA
On Board Diagnosis LogicNBEC0157The heated oxygen sensor 2 (rear) has a much longer switching
time between rich and lean than the heated oxygen sensor 1
(front). The oxygen storage capacity before the three way catalyst
causes the longer switching time. To judge the malfunctions of
heated oxygen sensor 2 (rear), ECM monitors whether the voltage
is unusually high during the various driving condition such as fuel-
cut.
Malfunction is detected when an excessively high voltage from the
sensor is sent to ECM.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0140, P0160 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Component Description
EC-277

5 CHECK HEATED OXYGEN SENSOR 2 (REAR)
With CONSULT-II
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Select ªFUEL INJECTIONº in ªACTIVE TESTº mode, and select ªHO2S2 (B1)/(B2)º as the monitor item with CONSULT-
II.
4. Check ªHO2S2 (B1)/(B2)º at idle speed when adjusting ªFUEL INJECTIONº to±25%.
SEF972Y
ªHO2S2 (B1)/(B2)º should be above 0.62V at least once when the ªFUEL INJECTIONº is +25%.
ªHO2S2 (B1)/(B2)º should be below 0.57V at least once when the ªFUEL INJECTIONº is þ25%.
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©GO TO 9.
NG©GO TO 8.
6 CHECK HEATED OXYGEN SENSOR 2 (REAR)-I
Without CONSULT-II
1. Start engine and drive vehicle at a speed of more than 70 km/h (43 MPH) for 2 consecutive minutes.
2. Stop vehicle with engine running.
3. Set voltmeter probes between ECM terminal 72 (HO2S2 bank 1 right signal) or 71 (HO2S2 bank 2 left signal) and
engine ground.
4. Check the voltage when revving up to 4,000 rpm under no load at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
SEF313XA
OK or NG
OK©GO TO 9.
NG©GO TO 7.
DTC P0140, P0160 HEATED OXYGEN SENSOR 2 (REAR) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Diagnostic Procedure (Cont'd)
EC-284

DescriptionNBEC0162SYSTEM DESCRIPTIONNBEC0162S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS)
Engine speedHeated
oxygen
sensor 2
heater
(rear) con-
trolHeated oxygen sensor 2 heat-
ers (rear)
Crankshaft position sensor (REF)
The ECM performs ON/OFF control of the heated oxygen sensor 2 heaters (rear) corresponding to the engine
speed.
OPERATIONNBEC0162S02
Engine speed rpm Heated oxygen sensor 2 heaters (rear)
Above 3,200 OFF
Below 3,200 ON
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0163Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)
HO2S2 HTR (B2)IIgnition switch: ON (Engine stopped)
IEngine is running above 3,200 rpm.OFF
IEngine is running below 3,200 rpm after driving for 2 minutes at a
speed of 70 km/h (43 MPH) or more.ON
ECM Terminals and Reference ValueNBEC0662Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
5 P/BHeated oxygen sensor
2 heater (rear) (bank
1)[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)
4 R/WHeated oxygen sensor
2 heater (rear) (bank
2)[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)
DTC P0141, P0161 HEATED OXYGEN SENSOR 2 HEATER (REAR) (BANK 1)/
(BANK 2)
Description
EC-286