Page 1177 of 2898

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
Page 1178 of 2898
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
Page 1179 of 2898

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
Page 1180 of 2898
SEF648Y
SEF011X
Without CONSULT-II
1) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminal 62 (HO2S1 sig-
nal) and engine ground.
3) Check the following with engine speed held at 2,000 rpm con-
stant under no load.
+The voltage fluctuates between 0 to 0.3V and 0.6 to 1.0V more
than 5 times within 10 seconds.
+The maximum voltage is over 0.6V at least one time.
+The minimum voltage is below 0.3V at least one time.
+The voltage never exceeds 1.0V.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0-
0.3V
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
Component Inspection (Cont'd)
EC-456
Page 1181 of 2898

DescriptionNJEC1223SYSTEM DESCRIPTIONNJEC1223S01
Sensor Input Signal to ECMECM func-
tionActuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speedHeated
oxygen
sensor 1
heater
(front) con-
trolHeated oxygen sensor 1 heater
(front)
The ECM performs ON/OFF control of the heated oxygen sensor 1 heater (front) corresponding to the engine
operating condition.
OPERATIONNJEC1223S02
Engine speed Heated oxygen sensor 1 heater (front)
Above 3,200 rpm OFF
Below 3,200 rpm ON
CONSULT-II Reference Value in Data Monitor
Mode
NJEC1224Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 HTR (B1)+Engine speed: Below 3,200 rpm ON
+Engine speed: Above 3,200 rpm OFF
ECM Terminals and Reference ValueNJEC1225Specification 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)
4 R/BHeated oxygen sensor 1
heater (front)[Engine is running]
+Engine speed is below 3,200 rpm.Approximately 0V
[Engine is running]
+Engine speed is above 3,200 rpm.BATTERY VOLTAGE
(11 - 14V)
HEATED OXYGEN SENSOR 1 HEATER (FRONT)QG
Description
EC-457
Page 1182 of 2898
Wiring DiagramNJEC1228SEDAN MODELS AND HATCHBACK MODELS WITH
ECM IN ENGINE COMPARTMENT
NJEC1228S03
HEC852
HEATED OXYGEN SENSOR 1 HEATER (FRONT)QG
Wiring Diagram
EC-458
Page 1183 of 2898
HATCHBACK MODELS WITH ECM IN CABINNJEC1228S04
HEC939
HEATED OXYGEN SENSOR 1 HEATER (FRONT)QG
Wiring Diagram (Cont'd)
EC-459
Page 1184 of 2898
Diagnostic ProcedureNJEC1229
1 CHECK OVERALL FUNCTION
1. Turn ignition switch ªONº.
2. Set the tester probe between ECM terminals 4 [HO2S1 Heater (front) signal] and ground.
3. Start engine and let it idle.
4. Check the voltage under the following conditions.
SEF239Z
OK or NG
OK©INSPECTION END
NG©GO TO 2.
2 CHECK POWER SUPPLY
1. Turn ignition switch ªOFFº.
2. Disconnect heated oxygen sensor 1 (front) harness connector.
SEF012XA
3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and ground with CONSULT-II or tester.
SEF934X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
HEATED OXYGEN SENSOR 1 HEATER (FRONT)QG
Diagnostic Procedure
EC-460