SFI SYSTEM, Diagnostic DTC:P0139

DTC Code DTC Name
P0139 Oxygen Sensor Circuit Slow Response (Bank 1 Sensor 2)

DESCRIPTION

In order to obtain a high purification rate for the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a Three-Way Catalytic Converter (TWC) is used. For the most efficient use of the TWC, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel ratio. The No. 2 heated oxygen sensor has the characteristic whereby its output voltage changes suddenly in the vicinity of the stoichiometric air fuel ratio. This is used to detect the oxygen concentration in the exhaust gas and provide the ECM with feedback to control the air fuel ratio. When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas increases. The No. 2 heated oxygen sensor informs the ECM of the lean condition (low voltage, i.e. less than 0.45 V). When the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas is reduced, and the No. 2 heated oxygen sensor informs the ECM of the rich condition (high voltage, i.e. more than 0.45 V). The ECM judges, using the voltage output of the No. 2 heated oxygen sensor, whether the air fuel ratio is rich or lean and controls the injection time accordingly. If a malfunction of the No. 2 heated oxygen sensor causes an output of abnormal voltage, the ECM is unable to perform accurate air fuel ratio control. The No. 2 heated oxygen sensor includes a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), a current flows to the heater in order to heat the sensor for accurate oxygen concentration detection.

A01VGWJE10
DTC No. DTC Detection Condition Trouble Area
P0139 While driving for 10 minutes or more at vehicle speed of 70 to 110 km/h (44 to 68 mph) with transmission in 5th, No. 2 heated oxygen sensor signal does not switch from rich to lean or vice versa for 50 seconds (3 trip detection logic).

  • Open or short in No. 2 heated oxygen sensor circuit

  • No. 2 heated oxygen sensor

  • Fuel pressure

  • Fuel injector assembly

  • Gas leak from exhaust system

WIRING DIAGRAM

Refer to DTC P0130 Click here.

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

DTC P0139 is detected when the vehicle is driven for 10 minutes or more at a constant vehicle speed of between 70 km/h (43 mph) and 100 km/h (62 mph) with the transmission gear selector lever in the 5th position.

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips


  • Sensor 1 refers to the sensor closest to the engine assembly.

  • Sensor 2 refers to the sensor farthest away from the engine assembly.

  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE


  1. CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO DTC P0139)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read DTCs.

      Result
      Result Proceed to
      DTC P0139 is output A
      DTC P0139 and other DTCs are output B

      Tech Tips

      If any DTCs other than P0139 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Warm up the engine at an engine speed of 2500 rpm for approximately 3 minutes.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

    6. Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

    7. Monitor the voltage output of the heated oxygen sensor and No. 2 heated oxygen sensor (O2S B1S1 and O2S B1S2) displayed on the tester.

      Tech Tips


      • The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.

      • The heated oxygen sensor has an output delay of a few seconds and the No. 2 heated oxygen sensor has a maximum output delay of approximately 20 seconds.

      • If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.

      Result
      The heated oxygen sensors reacts in accordance with increases and decreases of the fuel injection volume:
      +12.5% = Rich output
      Higher than 0.55 V
      -12.5% = Lean output
      Below 0.4 V
      A01VDMFE01

      The following procedure enables the technician to check and graph the voltage outputs of both the heated oxygen sensors.

      To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / O2S B1S1 and O2S B1S2; then press the view button.

      Tech Tips

      If the vehicle is short of fuel, the air fuel ratio becomes lean and the heated oxygen sensor DTCs are recorded, and then the MIL illuminates.

      Result
      Result Proceed to
      Case 2 A
      Case 3 B
      Case 1 C

    B

    CHECK WHETHER MISFIRE OCCURS Click here

    C

    CHECK WHETHER DTC OUTPUT RECURS (DTC P0139) Click here

    A

  3. CHECK HARNESS AND CONNECTOR (NO. 2 HEATED OXYGEN SENSOR - ECM)


    1. Disconnect the No. 2 heated oxygen sensor connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      B83-3 (OX1B) - B87-36 (OX1B) Always Below 1 Ω
      B83-1 (HT1B) - B87-41 (HT1B) Always Below 1 Ω
      B83-4 (E1) - B87-37 (O1B-) Always Below 1 Ω
      B83-3 (OX1B) or B87-36 (OX1B) - Body ground Always 10 kΩ or higher
      B83-1 (HT1B) or B87-41 (HT1B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. REPLACE NO. 2 HEATED OXYGEN SENSOR


    1. Replace No. 2 heated oxygen sensor Click here.


    NEXT

  5. CHECK WHETHER DTC OUTPUT RECURS (DTC P0139)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTCs Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the tester on.

    8. Start the engine and warm it up.

    9. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    10. Enter the following menus: Powertrain / Engine and ECT / DTC.

    11. Read the pending DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC P0139 is output B

    A

    END

    B

  6. CHECK WHETHER MISFIRE OCCURS


    1. Check the idling condition.

      OK
      Rough idling does not occur.

    NG

    TROUBLESHOOT MISFIRE Click here

    OK

  7. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    REPAIR OR REPLACE FUEL SYSTEM

    OK

  8. INSPECT FUEL INJECTOR ASSEMBLY (INJECTION AND VOLUME)


    1. Check the injector volume Click here.


    OK

    CHECK FOR EXHAUST GAS LEAK

    NG

    REPLACE FUEL INJECTOR ASSEMBLY Click here

  9. CHECK WHETHER DTC OUTPUT RECURS (DTC P0139)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear DTCs Click here.

    5. Turn the ignition switch off and wait for 30 seconds.

    6. Turn the ignition switch to ON.

    7. Turn the tester on.

    8. Start the engine and warm it up.

    9. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    10. Enter the following menus: Powertrain / Engine and ECT / DTC.

    11. Read the pending DTCs.

      Result
      Result Proceed to
      DTC P0139 is output A
      DTC is not output B

    A

    REPLACE NO. 2 HEATED OXYGEN SENSOR Click here

    B

    CHECK FOR INTERMITTENT PROBLEMS Click here