DTC P1144 HO2S1
EC-1033
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4.CHECK HO2S1 CONNECTOR FOR WATER
1. Turn ignition switch “OFF”.
2. Disconnect heated oxygen sensor 1 harness connector.
3. Check connectors for water.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace harness or connectors.
5.CHECK HEATED OXYGEN SENSOR 1 HEATER
Refer to EC-864, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 1.
6.CHECK HEATED OXYGEN SENSOR 1
Refer to EC-1033, "
Component Inspection" .
OK or NG
OK >> GO TO 7.
NG >> Replace heated oxygen sensor 1.
7.CHECK INTERMITTENT INCIDENT
Refer to EC-847, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
For circuit, refer to EC-901, "
Wiring Diagram" .
>>INSPECTION END
Component InspectionEBS00N0C
HEATED OXYGEN SENSOR 1
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “MANU TRIG” and adjust “TRIGGER POINT” to 100% in “DATA MONITOR” mode with CONSULT-
II.
3. Select “HO2S1 (B1)” and “HO2S1 MNTR (B1)”.
4. Hold engine speed at 2,000 rpm under no load during the follow-
ing steps.
5. Touch “RECORD” on CONSULT-II screen.Water should not exist.
PBIB0500E
SEF646Y
EC-1034
[QR20(WITH EURO-OBD)]
DTC P1144 HO2S1
6. Check the following.
●“HO2S1 MNTR (B1)” in “DATA MONITOR” mode changes
from “RICH” to “LEAN” to “RICH” 5 times in 10 seconds.
5 times (cycles) are counted as shown at right.
●“HO2S1 (B1)” voltage goes above 0.6V at least once.
●“HO2S1 (B1)” voltage goes below 0.3V at least once.
●“HO2S1 (B1)” 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 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 normal operating temperature.
2. Set voltmeter probes between ECM terminal 92 (HO2S1 signal) 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
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 InstallationEBS00N0D
HEATED OXYGEN SENSOR 1
Refer to EM-24, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .
SEF217YA
SEF648Y
PBIB0543E
DTC P1146 HO2S2
EC-1035
[QR20(WITH EURO-OBD)]
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DTC P1146 HO2S2PFP:226A0
Component DescriptionEBS00N0E
The heated oxygen sensor 2, after three way catalyst, 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 ModeEBS00N0F
Specification data are reference values.
ECM Terminals and Reference ValueEBS00N0G
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.
On Board Diagnosis LogicEBS00N0H
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 minimum voltage of sensor is
sufficiently low during the various driving condition such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
●Engine: After warming upRevving engine from idle up to 3,000
rpm quickly.0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
●Engine: After warming upRevving engine from idle up to 3,000
rpm quickly.LEAN←→ RICH
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
95 OR/BHeated oxygen sen-
sor 2[Engine is running]
●Warm-up condition
●Engine speed is 2,000 rpm.0 - Approximately 1.0V
PBIB0554E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1146
11 4 6Heated oxygen sensor
2 minimum voltage
monitoringThe minimum voltage from the sensor is not
reached to the specified voltage.
●Harness or connectors
(The sensor circuit is open or shorted)
●Heated oxygen sensor 2
●Fuel pressure
●Injectors
DTC P1146 HO2S2
EC-1037
[QR20(WITH EURO-OBD)]
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Procedure for COND2
1. While driving, release accelerator pedal completed with “OD”
OFF (A/T models only) from the above condition [step 8] until
“INCOMPLETE” at “COND2” on CONSULT-II screen has turned
to “COMPLETED” (It will take approximately 4 seconds.)
NOTE:
If “COMPLETE” already appears at “COND3” on CONSULT-
II screen before “Procedure for COND3” is conducted, it is
unnecessary 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-1039, "
Diagnostic Procedure" .
Overall Function CheckEBS00N0J
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 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 95 (HO2S2 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.)
The voltage should be below 0.50V at least once during this
procedure.
If the voltage can be confirmed in step 4, step 5 is not nec-
essary.
5. 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 be below 0.50V at least once during this
procedure.
6. If NG, go to EC-1039, "
Diagnostic Procedure" .
PBIB0556E
SEC775C
PBIB0550E
DTC P1146 HO2S2
EC-1039
[QR20(WITH EURO-OBD)]
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Diagnostic ProcedureEBS00N0L
1.RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 2.
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 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 1st trip DTC P0102 is displayed.
6. Erase the 1st trip DTC memory. Refer to EC-788, "
HOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION" .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0172. Refer to EC-940 .
No >> GO TO 3.
PBIB0494E
SEF215Z
PBIB0495E
EC-1040
[QR20(WITH EURO-OBD)]
DTC P1146 HO2S2
3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Check harness continuity between HO2S2 terminal 3 and
engine ground.
Refer to Wiring Diagram.
4. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to power in harness or con-
nectors.
4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 95 and HO2S2 terminal 2.
Refer to Wiring Diagram.
3. Check harness continuity between ECM terminal 95 or HO2S2 terminal 2 and ground.
Refer to Wiring Diagram.
4. Also check harness for short to ground or 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 HEATED OXYGEN SENSOR 2
Refer to EC-1040, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2.
6. CHECK INTERMITTENT INCIDENT
Refer to EC-847, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00N0M
HEATED OXYGEN SENSOR 2
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.Continuity should exist.
PBIB0500E
Continuity should exist.
Continuity should not exist.
DTC P1146 HO2S2
EC-1041
[QR20(WITH EURO-OBD)]
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3. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)” as the monitor item with CONSULT-II.
4. 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 0.50V 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 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 95 (HO2S2 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.)
The voltage should be above 0.68V at least once during this
procedure.
If the voltage is above 0.68V at step 4, step 5 is not neces-
sary.
5. Keep vehicle at idling for 10 minutes, then check 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 be below 0.50V at least once during this
procedure.
6. 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 InstallationEBS00N0N
HEATED OXYGEN SENSOR 2
Refer to EX-2, "EXHAUST SYSTEM" .
SEF662Y
PBIB0551E
PBIB0550E
EC-1042
[QR20(WITH EURO-OBD)]
DTC P1147 HO2S2
DTC P1147 HO2S2
PFP:226A0
Component DescriptionEBS00N0O
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
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 ModeEBS00N0P
Specification data are reference values.
ECM Terminals and Reference ValueEBS00N0Q
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.
On Board Diagnosis LogicEBS00N0R
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 (manifold) catalyst causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the maximum voltage of the sensor
is sufficiently high during the various driving condition such as fuel-
cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
●Engine: After warming upRevving engine from idle to 3,000
rpm quickly.0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
●Engine: After warming upRevving engine from idle to 3,000
rpm quickly.LEAN ←→ RICH
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
95 OR/BHeated oxygen sen-
sor 2[Engine is running]
●Warm-up condition
●Engine speed is 2,000 rpm.0 - Approximately 1.0V
SEF259VA
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1147
11 4 7Heated oxygen sensor
2 maximum voltage
monitoringThe maximum voltage from the sensor is not
reached to the specified voltage.
●Harness or connectors
(The sensor circuit is open or shorted)
●Heated oxygen sensor 2
●Fuel pressure
●Injectors
●Intake air leaks