2001 NISSAN ALMERA o2 sensor

7 CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to ªComponent Inspectionº, EC-448.
OK or NG
OK©GO TO 8.
NG©Replace intake air temperature sensor.
8 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
SEC516C
Component InspectionNJEC1740INTAKE AIR TEMPERATURE SENSORNJEC1740S01Models with Intake Air Temperature Sensor in Mass Air
Flow Sensor
NJEC1740S0101Check resistance between mass air flow sensor harness connec-
tor terminals 3 and 5.

Intake air temperature
ÉC (ÉF)Resistance kW
25 (77) 1.9 - 2.1
If NG, replace intake air temperature sensor.
SEF913W
Models with Intake Air Temperature Sensor on Intake
Air Duct
NJEC1740S0102Check resistance as shown in the figure.
INTAKE AIR TEMPERATURE SENSORQG
Diagnostic Procedure (Cont'd)
EC-448

SEF012P

Intake air temperature
ÉC (ÉF)Resistance kW
20 (68) 2.1 - 2.9
80 (176) 0.27 - 0.38
If NG, replace intake air temperature sensor.
INTAKE AIR TEMPERATURE SENSORQG
Component Inspection (Cont'd)
EC-449

SEF463R
SEF288D
Component DescriptionNJEC1214The heated oxygen sensor 1 (front) is placed into the exhaust
manifold. It detects the amount of oxygen in the exhaust gas com-
pared to the outside air. The heated oxygen sensor 1 (front) has a
closed-end tube made of ceramic zirconia. The zirconia generates
voltage from approximately 1V in richer conditions to 0V in leaner
conditions. The heated oxygen sensor 1 (front) signal is sent to the
ECM. The ECM adjusts the injection pulse duration to achieve the
ideal air-fuel ratio. The ideal air-fuel ratio occurs near the radical
change from 1V to 0V.
CONSULT-II Reference Value in Data Monitor
Mode
NJEC1215Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 (B1)
+Engine: After warming upMaintaining engine speed at 2,000
rpm0 - 0.3V¨Approx. 0.6 - 1.0V
HO2S1 MNTR
(B1)LEAN¨RICH
Changes more than 5 times during
10 seconds.
ECM Terminals and Reference ValueNJEC1216Specification 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)
62 WHeated oxygen sensor
1 (front)[Engine is running]
+After warming up to normal operating tempera-
ture and engine speed is 2,000 rpm0 - Approximately 1.0V
SEF008W
HEATED OXYGEN SENSOR 1 (FRONT)QG
Component Description
EC-450

Wiring DiagramNJEC1220SEDAN MODELS AND HATCHBACK MODELS WITH
ECM IN ENGINE COMPARTMENT
NJEC1220S03
HEC851
HEATED OXYGEN SENSOR 1 (FRONT)QG
Wiring Diagram
EC-451

HATCHBACK MODELS WITH ECM IN CABINNJEC1220S04
HEC937
HEATED OXYGEN SENSOR 1 (FRONT)QG
Wiring Diagram (Cont'd)
EC-452

Diagnostic ProcedureNJEC1221
1 INSPECTION START
Do you have CONSULT-II?
YesorNo
Ye s©GO TO 2.
No©GO TO 3.
2 CHECK OVERALL FUNCTION
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode with CONSULT-II.
3. Keep the engine speed at 2,000 rpm under no load, and make sure that the monitors fluctuate between LEAN and
RICH more than five times in 10 seconds.
SEF218Z
OK or NG
OK©INSPECTION END
NG©GO TO 4.
3 CHECK OVERALL FUNCTION
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 62 (HO2S1 signal) and engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
SEC518C
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©INSPECTION END
NG©GO TO 4.
HEATED OXYGEN SENSOR 1 (FRONT)QG
Diagnostic Procedure
EC-453

4 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
JEF104Y
3. Disconnect heated oxygen sensor 1 (front) harness connector.
SEF012XA
©GO TO 5.
5 RETIGHTEN HEATED OXYGEN SENSOR 1 (FRONT)
Loosen and retighten corresponding heated oxygen sensor 1 (front).
Tightening torque:
40 - 50 N´m (4.1 - 5.1 kg-m, 30 - 37 ft-lb)
©GO TO 6.
6 CHECK INPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 62 and heated oxygen sensor 1 (front) harness connector terminal 2.
Refer to wiring diagram.
Continuity should exist.
3. Check harness continuity between ECM terminal 62 (or terminal 2) and ground.
Continuity should not exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
HEATED OXYGEN SENSOR 1 (FRONT)QG
Diagnostic Procedure (Cont'd)
EC-454

7 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
Refer to ªComponent Inspectionº, EC-455.
OK or NG
OK©GO TO 8.
NG©Replace heated oxygen sensor 1 (front).
8 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
SEF646Y
SEF647Y
Component InspectionNJEC1222HEATED OXYGEN SENSOR 1 (FRONT)NJEC1222S01With CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Select ªMANU TRIGº in ªDATA MONITORº mode, and select
ªHO2S1 (B1)º and ªHO2S1 MNTR (B1)º.
3) Hold engine speed at 2,000 rpm under no load during the fol-
lowing steps.
4) Touch ªRECORDº on CONSULT-II screen.
5) Check the following.
+ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode changes from
ªRICHº to ªLEANº to ªRICHº 5 times in 10 seconds.
5 times (cycles) are counted as shown below:
R = ªHO2S1 MNTR (B1)º, ªRICHº
L = ªHO2S1 MNTR (B1)º, ªLEANº
+ªHO2S1 (B1)º voltage goes above 0.6V at least once.
+ªHO2S1 (B1)º voltage goes below 0.3V at least once.
+ªHO2S1 (B1)º voltage never exceeds 1.0V.
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.
HEATED OXYGEN SENSOR 1 (FRONT)QG
Diagnostic Procedure (Cont'd)
EC-455