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Home >> Infiniti >> 2023 >> QX50 Autograph >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (DTC/Circuit Diagnosis) (4 Of 4) >> DTC/Circuit Diagnosis >> DTC P2271: O2 Sensor Signal Bank 1 Sensor 2 >> DTC Description
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DTC Description

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching time.

GNSDB36085Courtesy of NISSAN
SYMBOL : 0.73 V

To judge the malfunctions of heated oxygen sensor 2, ECM monitors whether the maximum voltage of the sensor is sufficiently high during various driving conditions such as fuel cut.

DTC DETECTION LOGIC 

DTC CONSULT screen terms (Trouble diagnosis content) DTC detection condition
P2271 00 O2 sensor signal bank 1 sensor 2 (O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 2) Diagnosis condition -
Signal (terminal) Heated oxygen sensor 2 signal
Threshold
  • The maximum voltage from the sensor does not reach the specified voltage
  • ECM detects the heated oxygen sensor 2 circuit is short to ground.
Diagnosis delay time -

POSSIBLE CAUSE 

FAIL-SAFE 

Not applicable

DTC CONFIRMATION PROCEDURE 

  1. PRECONDITIONING 

    If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

    TESTING CONDITION: Check that "COOLANT TEMP/S" indicates between 0°C to 30°C (30°F to 86°F) before conducting following procedure.

    Will CONSULT be used?

    YES>>

    GO TO 2.

    NO>>

    GO TO 4.

  2. PERFORM DTC CONFIRMATION PROCEDURE 

    SYMBOL With CONSULT

    1. Turn ignition switch ON and select "DATA MONITOR" mode of "ENGINE" using CONSULT.
    2. Start engine and warm it up to the normal operating temperature.
    3. Turn ignition switch OFF and wait at least 10 seconds.
    4. Restart engine and keep the engine speed between 3, 500 and 4, 000 RPM for at least 1 minute under no load.
    5. Let engine idle for 1 minute.
    6. Check that "COOLANT TEMP/S" indicates more than 70°C (158°F).If not, warm up engine and go to next step when "COOLANT TEMP/S" indication reaches 70°C (158°F).
    7. Open engine hood.
    8. Select "HO2S2 (B1) P1147" in "HO2S2" in "DTC WORK SUPPORT" mode of "ENGINE" using CONSULT.
    9. Follow the instruction of CONSULT display.
      NOTE: SYMBOL It will take at most 10 minutes until "COMPLETED" is displayed.
    10. Touch "SELF-DIAG RESULTS"

    Is "OK" displayed on CONSULT screen?

    YES>>

    To check malfunction symptom before repair: Refer to Intermittent Incident .

    YES>>

    Confirmation after repair: INSPECTION END

    NG>>

    Proceed to Diagnosis Procedure .

    CAN NOT BE DIAGNOSED>>

    GO TO 3.

  3. PERFORM DTC CONFIRMATION PROCEDURE AGAIN 
    1. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
    2. Perform DTC confirmation procedure again.

    >>

    GO TO 2.

  4. PERFORM COMPONENT FUNCTION CHECK-1 

    SYMBOL Without CONSULT

    NOTE: SYMBOL Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.
    1. Start engine and warm it up to the normal operating temperature.
    2. Turn ignition switch OFF and wait at least 10 seconds.
    3. Restart engine and keep the engine speed between 3, 500 and 4, 000 RPM for at least 1 minute under no load.
    4. Let engine idle for 1 minute.
    5. Check the voltage between ECM harness connector terminals under the following conditions.
      ECM Condition Voltage
      Connector + -
      Terminal
      F52 77 76 Revving up to 4, 000 RPM quickly under no load at least 10 times. (Depress and release the accelerator pedal as quickly as possible.) The voltage should be above 0.73 V at least once during this procedure.

    Is the inspection result normal?

    YES>>

    To check malfunction symptom before repair: Refer to Intermittent Incident .

    YES>>

    Confirmation after repair: INSPECTION END

    NO>>

    GO TO 5.

  5. PERFORM COMPONENT FUNCTION CHECK-2 

    SYMBOL Without CONSULT Check the voltage between ECM harness connector terminals under the following conditions.

    ECM Condition Voltage
    Connector + -
    Terminal
    F52 77 76 Keeping engine at idle for 10 minutes. The voltage should be above 0.73 V at least once during this procedure.

    Is the inspection result normal?

    YES>>

    To check malfunction symptom before repair: Refer to Intermittent Incident .

    YES>>

    Confirmation after repair: INSPECTION END

    NO>>

    GO TO 6.

  6. PERFORM COMPONENT FUNCTION CHECK-3 

    SYMBOL Without CONSULT Check the voltage between ECM harness connector terminals under the following conditions.

    CAUTION:

    Always drive vehicle at a safe speed.

    ECM Condition Voltage
    Connector + -
    Terminal
    F52 77 76 Coasting from 80 km/h (50 MPH) in D position. The voltage should be above 0.73 V at least once during this procedure.

    Is the inspection result normal?

    YES>>

    To check malfunction symptom before repair: Refer to Intermittent Incident .

    YES>>

    Confirmation after repair: INSPECTION END

    NO>>

    Proceed to Diagnosis Procedure .

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