2003 NISSAN ALMERA N16 ecm

EC-172
[QG (WITH EURO-OBD)]
DTC P0138 HO2S2
DTC P0138 HO2S2
PFP:226A0
Component DescriptionEBS00K69
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeEBS00K6A
Specification data are reference values.
On Board Diagnosis LogicEBS00K6B
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity before the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the voltage is unusually high during
the various driving condition such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
●Engine: After warming up
●Keeping the engine speed
between 3,500 and 4,000 rpm
for one minute and at idle for
one minute under no loadRevving engine from idle to 3,000
rpm quickly.0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
●Engine: After warming up
●Keeping the engine speed
between 3,500 and 4,000 rpm
for one minute and at idle for
one minute under no loadRevving engine from idle to 3,000
rpm quickly.LEAN ←→ RICH
SEF305UA
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0138
0138Heated oxygen sensor 2
circuit high voltageAn excessively high voltage from the sensor
is sent to ECM.
●Harness or connectors
(The sensor circuit is open or shorted.)
●Heated oxygen sensor 2

DTC P0138 HO2S2
EC-175
[QG (WITH EURO-OBD)]
C
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EC
Specification 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.
Diagnostic ProcedureEBS00K6E
1.RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 2.
2.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect heated oxygen sensor 2 harness connector.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 74 and HO2S2
terminal 3.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 W Heated oxygen sensor 2[Engine is running]
●Warm-up condition
●Engine speed is 3,000 rpm after the following
conditions are met.
●Keeping the engine speed between 3,500 and
4,000 rpm for one minute and at idle for one
minute under no load.0 - Approximately 1.0V
74 BHeated oxygen sensor
ground[Engine is running]
●Idle speedApproximately 0V
MBIB0095E
Continuity should exist.
MBIB0256E

EC-176
[QG (WITH EURO-OBD)]
DTC P0138 HO2S2
3. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 16 and HO2S2 terminal 2.
Refer to Wiring Diagram.
2. Check harness continuity between ECM terminal 16 or HO2S2 terminal 2 and ground.
Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK HO2S2 CONNECTOR FOR WATER
Check connectors for water.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace harness or connector.
5. CHECK HEATED OXYGEN SENSOR 2
Refer to EC-176, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2.
6. CHECK INTERMITTENT INCIDENT
Refer to EC-109, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00K6F
HEATED OXYGEN SENSOR 2
With CONSULT-II
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no
load.
4. Let engine idle for one minute.
5. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)” as the monitor item with CONSULT-II.Continuity should exist.
Continuity should not exist.
Water should not exist.
SEF662Y

DTC P0138 HO2S2
EC-177
[QG (WITH EURO-OBD)]
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EC
6. Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)” should be above 0.68V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)” should be below 0.56V at least once when the “FUEL INJECTION” is −25%.
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 system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-II
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no
load.
4. Let engine idle for one minute.
5. Set voltmeter probes between ECM terminal 16 (HO2S2 signal) and engine ground.
6. 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 during this
procedure.
If the voltage is above 0.68V at step 6, step 7 is not neces-
sary.
7. Keep vehicle idling for 10 minutes, then check voltage. Or check
the voltage when coasting from 80 km/h (50 MPH) in “D” posi-
tion with “OD” OFF (A/T) 3rd gear position (M/T).
The voltage should be below 0.56V at least once during this
procedure.
8. If NG, replace heated oxygen sensor 2.
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 system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Removal and InstallationEBS00K6G
HEATED OXYGEN SENSOR 2
Refer to FE-10.
SEF244YA
MBIB0020E

EC-178
[QG (WITH EURO-OBD)]
DTC P0139 HO2S2
DTC P0139 HO2S2
PFP:226A0
Component DescriptionEBS00K6H
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeEBS00K6I
Specification data are reference values.
On Board Diagnosis LogicEBS00K6J
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity before the three way catalyst causes the longer
switching time. To judge the malfunctions of heated oxygen sensor
2, ECM monitors whether the switching response of the sensor's
voltage is faster than specified during the various driving condition
such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
●Engine: After warming up
●Keeping the engine speed
between 3,500 and 4,000 rpm
for one minute and at idle for
one minute under no loadRevving engine from idle to 3,000
rpm quickly.0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
●Engine: After warming up
●Keeping the engine speed
between 3,500 and 4,000 rpm
for one minute and at idle for
one minute under no loadRevving engine from idle to 3,000
rpm quickly.LEAN ←→ RICH
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139Heated oxygen sensor 2
circuit slow responseIt takes more time for the sensor to respond
between rich and lean than the specified time.
●Harness or connectors
(The sensor circuit is open or shorted.)
●Heated oxygen sensor 2
●Fuel pressure
●Injectors
●Intake air leaks

EC-180
[QG (WITH EURO-OBD)]
DTC P0139 HO2S2
Procedure for COND2
1. While driving, release accelerator pedal completely with ″OD″
OFF (A/T models only) from the above condition [step 9] until
“INCOMPLETE” at “COND2” on CONSULT-II screen has turned
to “COMPLETED”. (It will take approximately 4 seconds.)
NOTE:
If “COMPLETED” already appears at “COND3” on CONSULT-II
screen before “Procedure for COND3” is conducted, it is unnec-
essary to conduct step 1 in “Procedure for COND3”.
Procedure for COND3
1. Stop vehicle and let it idle until “INCOMPLETE” of “COND3” on
CONSULT-II screen has turned to “COMPLETED”. (It will take a
maximum of approximately 6 minutes.)
2. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULTS”.
If “NG” is displayed, refer to EC-182, "
Diagnostic Procedure" .
If″CAN NOT BE DIAGNOSED″ is displayed, perform the follow-
ing.
a. Turn ignition switch ″OFF″ and leave the vehicle in a cool place
(soak the vehicle).
b. Turn ignition switch ″ON″ and select ″COOLANTEMP/S″ in
″DATA MONITOR″ mode with CONSULT-II.
c. Start engine and warm it up while monitoring ″COOLANTEMP/S″ indication on CONSULT-II.
d. When ″COOLANTEMP/S″ indication reaches to 70°C (158°F), go to ″Procedure for COND 1″ step 3.
Overall Function CheckEBS00K6L
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a
DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch ″OFF″ and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no
load.
4. Let engine idle for one minute.
5. Set voltmeter probes between ECM terminal 16 (HO2S2 signal) and engine ground.
6. 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.)
A change of voltage should be more than 0.06V for 1 sec-
ond during this procedure.
If the voltage can be confirmed in step 6, step 7 is not nec-
essary.
7. Keep vehicle at idling for 10 minutes, then check the voltage. Or
check the voltage when coasting from 80 km/h (50 MPH) in ″D″
position with ″OD″ OFF (A/T), 3rd gear position (M/T).
The voltage should change at more than 0.06V for 1 second
during this procedure.
8. If NG, go to EC-182, "
Diagnostic Procedure" .
PBIB0553E
SEF668Y
MBIB0020E

EC-182
[QG (WITH EURO-OBD)]
DTC P0139 HO2S2
Specification 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.
Diagnostic ProcedureEBS00K6N
1. RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 2.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 W Heated oxygen sensor 2[Engine is running]
●Warm-up condition
●Engine speed is 3,000 rpm after the following
conditions are met.
●Keeping the engine speed between 3,500 and
4,000 rpm for one minute and at idle for one
minute under no load.0 - Approximately 1.0V
74 BHeated oxygen sensor
ground[Engine is running]
●Idle speedApproximately 0V
MBIB0095E

DTC P0139 HO2S2
EC-183
[QG (WITH EURO-OBD)]
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EC
2.CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode
with CONSULT-II.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P0172 detected?
Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch “OFF”.
3. Disconnect mass air flow sensor harness connector, and restart
and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Make sure that DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-48, "
HOW TO ERASE
EMISSION-RELATED DIAGNOSTIC INFORMATION" .
7. Make sure that DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P0172 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to EC-186 or EC-193 .
No >> GO TO 3.
3.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal 74 and HO2S2
terminal 3.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
SEF215Z
MBIB0096E
Continuity should exist.
MBIB0256E