2001 NISSAN ALMERA o2 sensor

SEF327R
Component DescriptionNJEC0171The heated oxygen sensor 2 (rear), after three way catalyst, moni-
tors the oxygen level in the exhaust gas.
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
NJEC0172Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
+Engine: After warming upRevving engine from idle to 3,000
rpm0 - 0.3V¨Approx. 0.6 - 1.0V
HO2S2 MNTR
(B1)LEAN¨RICH
ECM Terminals and Reference ValueNJEC0173Specification 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)
63 LHeated oxygen sensor 2
(rear)[Engine is running]
+After warming up to normal operating tempera-
ture and revving engine from idle to 2,000 rpm0 - Approximately 1.0V
SEF305U
On Board Diagnosis LogicNJEC0174The 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 or not the
voltage is too high during various driving conditions such as fuel-
cut.
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0140
0140+An excessively high voltage from the sensor is sent to
ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Heated oxygen sensor 2 (rear)
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Component Description
EC-284

SEF189Y
DTC Confirmation ProcedureNJEC0175NOTE:
If ªDTC Confirmation Procedure º has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
With CONSULT-II
1) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II.
2) Start engine and drive vehicle at a speed of more than 70 km/h
(43 MPH) for 2 consecutive minutes.
3) Stop vehicle with engine running.
4) Let engine idle for 1 minute.
5) Maintain the following conditions for at least 5 consecutive
minutes.
ENG SPEED Above 1,500 rpm
Selector lever Suitable position
6) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-288.
SEF032X
Overall Function CheckNJEC0176Use this procedure to check the overall function of the heated oxy-
gen sensor 2 (rear) circuit. During this check, a 1st trip DTC might
not be confirmed.
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 terminals 63 (HO2S2 sig-
nal) and engine ground.
4) Check the voltage after revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be below 2V during this procedure.
5) If NG, go to ªDiagnostic Procedureº, EC-288.
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
DTC Confirmation Procedure
EC-285

Wiring DiagramNJEC0177SEDAN MODELS AND HATCHBACK MODELS WITH
ECM IN ENGINE COMPARTMENT
NJEC0177S03
HEC787
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Wiring Diagram
EC-286

HATCHBACK MODELS WITH ECM IN CABINNJEC0177S04
HEC940
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Wiring Diagram (Cont'd)
EC-287

Diagnostic ProcedureNJEC0178
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
JEF104Y
©GO TO 2.
2 CHECK INPUT SIGNAL CIRCUIT
1. Disconnect heated oxygen sensor 2 (rear) harness connector and ECM harness connector.
SEF160Z
2. Check harness continuity between ECM terminal 63 and heated oxygen sensor 2 (rear) harness connector terminal 1.
Refer to wiring diagram.
Continuity should exist.
3. Check harness continuity between ECM terminal 63 [or heated oxygen sensor 2 (rear) harness connector terminal 1]
and ground.
Continuity should not exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the harness for open or short between heated oxygen sensor 2 (rear) and ECM.
©Repair open circuit or short to ground or short to power in harness or connectors.
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Diagnostic Procedure
EC-288

4 CHECK GROUND CIRCUIT
1. Check harness continuity between heated oxygen sensor 2 (rear) harness connector terminal 4 and engine ground.
Refer to wiring diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK HARNESS CONNECTOR
Check heated oxygen sensor 2 (rear) harness connector for water.
Water should not exist.
OK or NG
OK©GO TO 6.
NG©Repair or replace harness connector.
6 CHECK HEATED OXYGEN SENSOR 2 (REAR)
Refer to ªComponent Inspectionº, EC-289.
OK or NG
OK©GO TO 7.
NG©Replace heated oxygen sensor 2 (rear).
7 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
SEF662Y
Component InspectionNJEC0179HEATED OXYGEN SENSOR 2 (REAR)NJEC0179S01With 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)º as the monitor item with CONSULT-II.
4) Check ªHO2S2 (B1)º at idle speed when adjusting ªFUEL
INJECTIONº to±25%.
ªHO2S2 (B1)º should be above 0.68V at least once when
the ªFUEL INJECTIONº is +25%.
ªHO2S2 (B1)º should be below 0.56V 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.
+Before installing new oxygen sensor, clean exhaust sys-
tem threads using Oxygen Sensor Thread Cleaner tool
and approved anti-seize lubricant.
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Diagnostic Procedure (Cont'd)
EC-289

SEF244YA
SEF032X
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 terminals 63 (HO2S2 sig-
nal) 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.)
The voltage should be above 0.68V at least once.
If the voltage is above 0.68V at step 4, step 5 is not nec-
essary.
5) Check the voltage when revving up to 6,000 rpm under no
load. Or keep vehicle at idling for 10 minutes, then check the
voltage. Or check the voltage when coasting from 80 km/h (50
MPH) in 3rd gear position (M/T), D position with ªODº OFF
(A/T).
The voltage should be below 0.56V at least once.
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.
+Before installing new oxygen sensor, clean exhaust sys-
tem threads using Oxygen Sensor Thread Cleaner tool
and approved anti-seize lubricant.
DTC P0140 HEATED OXYGEN SENSOR 2 (REAR) (HIGH VOLTAGE)QG
Component Inspection (Cont'd)
EC-290

DescriptionNJEC0180SYSTEM DESCRIPTIONNJEC0180S01
Sensor Input Signal to ECMECM func-
tionActuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speedHeated
oxygen
sensor 2
heater
(rear) con-
trolHeated oxygen sensor 2 heater
(rear)
The ECM performs ON/OFF control of the heated oxygen sensor 2 heater (rear) corresponding to the engine
speed.
OPERATIONNJEC0180S02
Engine condition Heated oxygen sensor 2 heater (rear)
Engine stopped OFF
Engine is running. After driving for 2 minutes at a speed
of 70 km/h (43 MPH) or moreON
Engine speed above 3,600 rpm OFF
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0181Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)+Engine speedBelow 3,600 rpm [After driving for 2 minutes at a
speed of 70 km/h (43 MPH) or more]ON
Above 3,600 rpm OFF
+Ignition switch ON (Engine stopped) OFF
ECM Terminals and Reference ValueNJEC0182Specification 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)
3 W/RHeated oxygen sensor 2
heater (rear)[Engine is running]
+Engine speed is below 3,600 rpm [After driving
for 2 minutes at a speed of 70 km/h (43 MPH) or
more]Approximately 0.7V
[Engine is running]
+Engine speed is above 3,600 rpm
BATTERY VOLTAGE
(11 - 14V)
[Ignition switch ªONº]
+Engine stopped
DTC P0141 HEATED OXYGEN SENSOR 2 HEATER (REAR)QG
Description
EC-291