EC-968
[QR20(WITH EURO-OBD)]
DTC P0420 THREE WAY CATALYST FUNCTION
DTC P0420 THREE WAY CATALYST FUNCTION
PFP:20905
On Board Diagnosis LogicEBS00MXP
The ECM monitors the switching frequency ratio of heated oxygen
sensors 1 and 2.
A three way catalyst (Manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decreases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2
approaches a specified limit value, the three way catalyst (Manifold)
malfunction is diagnosed.
DTC Confirmation ProcedureEBS00MXQ
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch “OFF” and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
TESTING CONDITION:
●Open engine hood before conducting the following procedure.
●Do not hold engine speed for more than the specified minutes below.
1. Turn ignition switch “ON”.
2. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUP-
PORT” mode with CONSULT-II.
3. Start engine.
4. Rev engine up to 2,000 to 3,000 rpm and hold it for 3 consecu-
tive minutes then release the accelerator pedal completely.
If “INCMP” of “CATALYST” changed to “COMPLT”, go to step 7
5. Wait 5 seconds at idle.
SEF484YF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0420
0420Catalyst system effi-
ciency below threshold
●Three way catalyst (Manifold) does not oper-
ate properly.
●Three way catalyst (Manifold) does not have
enough oxygen storage capacity.
●Three way catalyst (Manifold)
●Exhaust tube
●Intake air leaks
●Fuel injectors
●Fuel injector leaks
●Spark plug
●Improper ignition timing
PBIB0566E
DTC P0420 THREE WAY CATALYST FUNCTION
EC-969
[QR20(WITH EURO-OBD)]
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6. Rev engine up to 2,000 to 3,000 rpm and maintain it until
“INCMP” of “CATALYST” changes to “CMPLT” (It will take
approximately 5 minutes).
If not “CMPLT”, stop engine and cool it down to less than 70°C
(158°F) and then retest from step 1.
7. Select “SELF-DIAG RESULTS” mode with CONSULT-II.
8. Confirm that the 1st trip DTC is not detected.
If the 1st trip DTC is detected, go to EC-970, "
Diagnostic Proce-
dure" .
Overall Function CheckEBS00MXR
Use this procedure to check the overall function of the three way catalyst (Manifold). During this check, a DTC
might not be confirmed.
CAUTION:
Always drive vehicle at a safe speed.
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 voltmeters probes between ECM terminal 92 (HO2S1 sig-
nal) and engine ground, and ECM terminal 95 (HO2S2 signal)
and engine ground.
4. Keep engine speed at 2,000 rpm constant under no load.
5. Make sure that the voltage switching frequency (high & low)
between ECM terminal 95 and engine ground is very less than
that of ECM terminal 92 and engine ground.
Switching frequency ratio = A/B
A: Heated oxygen sensor 2 voltage switching frequency
B: Heated oxygen sensor 1 voltage switching frequency
This ratio should be less than 0.75.
If the ratio is greater than above, it means three way catalyst
(manifold) does not operate properly. Go to EC-970, "
Diagnostic
Procedure" .
NOTE:
If the voltage at terminal 92 does not switch periodically more than 5
times within 10 seconds at step 5, perform trouble diagnosis for “DTC P0133” first. (See EC-905
.)
PBIB0567E
SEF535Z
PBIB0543E
PBIB0550E
EC-972
[QR20(WITH EURO-OBD)]
DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VALVE
DTC P0444, P0445 EVAP CANISTER PURGE VOLUME CONTROL SOLENOID
VA LV E
PFP:14920
DescriptionEBS00MXT
SYSTEM DESCRIPTION
This system controls flow rate of fuel vapor from the EVAP canister. The opening of the vapor by-pass pas-
sage in the EVAP canister purge volume control solenoid valve changes to control the flow rate. The EVAP
canister purge volume control solenoid valve repeats ON/OFF operation according to the signal sent from the
ECM. The opening of the valve varies for optimum engine control. The optimum value stored in the ECM is
determined by considering various engine conditions. When the engine is operating, the flow rate of fuel vapor
from the EVAP canister is regulated as the air flow changes.
COMPONENT DESCRIPTION
The EVAP canister purge volume control solenoid valve uses a ON/
OFF duty to control the flow rate of fuel vapor from the EVAP canis-
ter. The EVAP canister purge volume control solenoid valve is
moved by ON/OFF pulses from the ECM. The longer the ON pulse,
the greater the amount of fuel vapor that will flow through the valve.
CONSULT-II Reference Value in Data Monitor ModeEBS00MXU
Specification data are reference values.
ECM Terminals and Reference ValueEBS00MXV
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II
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.
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EVAP can-
ister purge
flow con-
trolEVAP canister purge volume
control solenoid valve Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Accelerator pedal position sensor Closed throttle position
Heated oxygen sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Vehicle speed sensor Vehicle speed
SEF337U
MONITOR ITEM CONDITION SPECIFICATION
PURG VOL C/V
●Engine: After warming up
●Shift lever: N
●Air conditioner switch: OFF
●No-loadIdle 0%
2,000 rpm 20 - 30%
DTC P1143 HO2S1
EC-1023
[QR20(WITH EURO-OBD)]
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DTC P1143 HO2S1PFP:22690
Component DescriptionEBS00MZW
The heated oxygen sensor 1 is placed into the exhaust manifold. It
detects the amount of oxygen in the exhaust gas compared to the
outside air. The heated oxygen sensor 1 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 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 ModeEBS00MZX
Specification data are reference values.
ECM Terminals and Reference ValueEBS00MZY
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.
SEF463R
SEF288D
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)
●Engine: After warming upMaintaining engine speed at 2,000
rpmLEAN←→ RICH
Changes more than 5 times dur-
ing 10 seconds.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
92 G/WHeated oxygen sen-
sor 1[Engine is running]
●Warm-up condition
●Engine speed is 2,000 rpm.0 - Approximately 1.0V (Periodi-
cally change)
EC-1024
[QR20(WITH EURO-OBD)]
DTC P1143 HO2S1
On Board Diagnosis Logic
EBS00MZZ
To judge the malfunction, the output from the heated oxygen sensor
1 is monitored to determine whether the “rich” output is sufficiently
high and whether the “lean” output is sufficiently low. When both the
outputs are shifting to the lean side, the malfunction will be detected.
DTC Confirmation ProcedureEBS00N00
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch “OFF” and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
●Always perform at a temperature above −10°C (14°F).
●Before performing following procedure, confirm that battery voltage is more than 11V at idle.
WITH CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine and wait at least 10 seconds.
3. Turn ignition switch “ON” and select “HO2S1 (B1) P1143” of “HO2S1” in “DTC WORK SUPPORT” mode
with CONSULT-II.
4. Touch “START”.
5. Start engine and let it idle for at least 3 minutes.
NOTE:
Never raise engine speed above 3,600 rpm after this step. If
the engine speed limit is exceeded, return to step 5.
SEF300U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1143
11 4 3Heated oxygen sensor
1 lean shift monitoringThe maximum and minimum voltage from the
sensor are not reached to the specified volt-
ages.
●Heated oxygen sensor 1
●Heated oxygen sensor 1 heater
●Fuel pressure
●Injectors
●Intake air leaks
PBIB0546E
DTC P1143 HO2S1
EC-1025
[QR20(WITH EURO-OBD)]
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6. When the following conditions are met, “TESTING” will be dis-
played on the CONSULT-II screen. Maintain the conditions con-
tinuously until “TESTING” changes to “COMPLETED”. (It will
take approximately 50 seconds or more.)
If “TESTING” is not displayed after 5 minutes, retry from
step 2.
7. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULTS”. If “NG” is displayed, refer to EC-1025, "
Diagnostic
Procedure" .
Overall Function CheckEBS00N01
Use this procedure to check the overall function of the heated oxygen sensor 1 circuit. During this check, a
DTC might not be confirmed.
WITH GST
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 one of the following with engine speed held at 2,000 rpm
constant under no load.
–The maximum voltage is over 0.6V at least one time.
–The minimum voltage is over 0.1V at least one time.
4. If NG, go to EC-1025, "
Diagnostic Procedure" .
Diagnostic ProcedureEBS00N02
1.RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 2.
ENG SPEED 1,400 - 3,200 rpm
Vehicle speed Less than 100 km/h (62 MPH)
B/FUEL SCHDL 2.9 - 14.5 msec
Selector lever Suitable position
PBIB0547E
SEC769C
PBIB0543E
PBIB0494E
EC-1026
[QR20(WITH EURO-OBD)]
DTC P1143 HO2S1
2. RETIGHTEN HEATED OXYGEN SENSOR 1
Loosen and retighten heated oxygen sensor 1.
>> GO TO 3.
3. 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 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 DTC P0102 is displayed.
6. Erase the 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 P0171 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171. Refer to EC-934 .
No >> GO TO 4.
4. CHECK HEATED OXYGEN SENSOR 1 HEATER
Refer to EC-864, "
Component Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Replace heated oxygen sensor 1.Tightening torque: 40 - 50 N·m (4.1 - 5.1 kg-m, 30 - 37 ft-lb)
PBIB0499E
SEF215Z
PBIB0495E
DTC P1143 HO2S1
EC-1027
[QR20(WITH EURO-OBD)]
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5.CHECK HEATED OXYGEN SENSOR 1
Refer to EC-1027, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 1.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-847, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
For circuit, refer to EC-901, "
Wiring Diagram" .
>>INSPECTION END
Component InspectionEBS00N03
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.
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.
SEF646Y
SEF217YA
SEF648Y