2001 INFINITI QX4 engine

SEF308XB
Overall Function CheckNBEC0113Use this procedure to check the overall function of the heated oxy-
gen sensor 1 (front) circuit. During this check, a 1st trip DTC might
not be confirmed.
WITH GSTNBEC0113S011) Start engine and warm it up to normal operating temperature.
2) Set voltmeter probes between ECM terminal 63 (HO2S1 bank
1 right signal) or 62 (HO2S1 bank 2 left signal) and engine
ground.
3) Check the following with engine speed held at 2,000 rpm con-
stant under no load.
IThe voltage fluctuates between 0 to 0.3V and 0.6 to 1.0V more
than 5 times within 10 seconds.
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
4) If NG, go to ªDiagnostic Procedureº, EC-224.
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DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Overall Function Check
EC-221

Diagnostic ProcedureNBEC0115
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
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©GO TO 2.
2 RETIGHTEN HEATED OXYGEN SENSOR 1 (FRONT)
Loosen and retighten corresponding heated oxygen sensor 1 (front).
Tightening torque:
40 - 60 N´m (4.1 - 6.1 kg-m, 30 - 44 ft-lb)
©GO TO 3.
3 CHECK FOR EXHAUST AIR LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust air leak before three way catalyst.
SEF099P
OK or NG
OK©GO TO 4.
NG©Repair or replace.
4 CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK©GO TO 5.
NG©Repair or replace.
DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure
EC-224

5 CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªSELF-LEARNING CONTº in ªWORK SUPPORTº mode with CONSULT-II.
3. Clear the self-learning control coefficient by touching ªCLEARº.
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4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 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 ªOFFº.
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 connector.
5. Make sure 1st trip DTC P0100 is displayed.
6. Erase the 1st trip DTC memory. Refer to ªHOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATIONº,
EC-72.
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
YesorNo
Ye s©Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-294,
302.
No©GO TO 6.
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DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-225

9 CHECK MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 61 (Mass air flow sensor signal) and ground.
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4. If the voltage is out of specification, disconnect mass air flow sensor harness connector and connect it again.
Then repeat above check.
OK or NG
OK©GO TO 10.
NG©Replace mass air flow sensor.
10 CHECK PCV VALVE
1. Install all removed parts.
2. Start engine and let it idle.
3. Remove PCV valve ventilation hose from PCV valve.
4. Make sure that a hissing noise will be heard as air passes through it and a strong vacuum should be felt immediately
when a finger is placed over valve inlet.
SEC137A
OK or NG
OK (With CONSULT-II)©GO TO 11.
OK (Without CONSULT-
II)©GO TO 12.
NG©Replace PCV valve.
DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-228

11 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select ªMANU TRIGº and adjust ªTRIGGER POINTº to 100% in ªDATA MONITORº mode with CONSULT-II.
3. Select ªHO2S1 (B1)/(B2)º and ªHO2S1 MNTR (B1)/(B2)º.
4. Hold engine speed at 2,000 rpm under no load during the following steps.
5. Touch ªRECORDº on CONSULT-II screen.
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6. Check the following.
IªHO2S1 MNTR (B1)/(B2)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.
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IªHO2S1 (B1)/(B2)º voltage goes above 0.6V at least once.
IªHO2S1 (B1)/(B2)º voltage goes below 0.3V at least once.
IªHO2S1 (B1)/(B2)º voltage never exceeds 1.0V.
SEF648Y
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©GO TO 14.
NG©GO TO 13.
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DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-229

12 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 63 (HO2S1 bank 1 right signal) or 62 (HO2S1 bank 2 left signal) and
engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
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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©GO TO 14.
NG©GO TO 13.
13 REPLACE HEATED OXYGEN SENSOR 1 (FRONT)
1. Turn ignition switch ªOFFº.
2. Check heated oxygen sensor 1 (front) harness protector color.
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©Replace malfunctioning heated oxygen sensor 1 (front).
14 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P0133, P0153 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(RESPONSE MONITORING)
Diagnostic Procedure (Cont'd)
EC-230

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SEF288D
Component DescriptionNBEC0116The heated oxygen sensor 1 (front) is placed into the front tube. It
detects the amount of oxygen in the exhaust gas compared 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
NBEC0117Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
HO2S1 (B1)
HO2S1 (B2)
IEngine: After warming upMaintaining engine speed at 2,000
rpm0 - 0.3V+,Approx. 0.6 - 1.0V
HO2S1 MNTR
(B1)
HO2S1 MNTR
(B2)LEAN+,RICH
Changes more than 5 times during
10 seconds.
ECM Terminals and Reference ValueNBEC0656Specification 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)
63 GHeated oxygen sensor
1 (front) (bank 1)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
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DTC P0134, P0154 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
Component Description
EC-231

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
62 G/BHeated oxygen sensor
1 (front) (bank 2)[Engine is running]
IWarm-up condition
IEngine speed is 2,000 rpm.0 - Approximately 1.0V (Peri-
odically change)
SEF059V
SEF301UA
On Board Diagnosis LogicNBEC0119To judge the malfunction, the diagnosis checks that the heated
oxygen sensor 1 (front) output is not inordinately high.
Malfunction is detected when an excessively high voltage from the
sensor is sent to ECM.
Possible CauseNBEC0436IHarness or connectors
(The sensor circuit is open or shorted.)
IHeated oxygen sensor 1 (front)
SEF174Y
DTC Confirmation ProcedureNBEC0120NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
WITH CONSULT-IINBEC0120S011) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch ªOFFº and wait at least 10 seconds.
3) Turn ignition switch ªONº.
4) Select ªDATA MONITORº mode with CONSULT-II.
DTC P0134, P0154 HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1)/(BANK 2)
(HIGH VOLTAGE)
ECM Terminals and Reference Value (Cont'd)
EC-232