SFI SYSTEM, Diagnostic DTC:P0136,P0137,P0138 and P0139

DTC Code DTC Name
P0136 O2 Sensor Circuit Bank 1 Sensor 2
P0137 O2 Sensor Circuit Low Voltage Bank 1 Sensor 2
P0138 O2 Sensor Circuit High Voltage Bank 1 Sensor 2
P0139 O2 Sensor Circuit Slow Response Bank 1 Sensor 2

DESCRIPTION

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel level. For the purpose of helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor (sensor 2) is used. The heated oxygen sensor (sensor 2) is located behind the three-way catalytic converter, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).

When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The heated oxygen sensor (sensor 2) indicates to the ECM that the post-three-way catalytic converter air fuel ratio is lean (low voltage, i.e. less than 0.45 V). Conversely, when the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas becomes lean. The heated oxygen sensor (sensor 2) indicates to the ECM that the post-three-way catalytic converter air fuel ratio is rich (high voltage, i.e. more than 0.45 V). The heated oxygen sensor (sensor 2) has the property of changing its output voltage drastically when the air fuel ratio is close to the stoichiometric level. The ECM uses the supplementary information from the heated oxygen sensor (sensor 2) to determine whether the air fuel ratio after the three-way catalytic converter is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the heated oxygen sensor (sensor 2) is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.

A330219E01

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0136

O2 Sensor Circuit Bank 1 Sensor 2

Open in heated oxygen sensor (sensor 2) circuit.

  • Heated oxygen sensor (sensor 2)

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P0137

O2 Sensor Circuit Low Voltage Bank 1 Sensor 2

Short to ground in heated oxygen sensor (sensor 2) circuit.

  • Heated oxygen sensor (sensor 2)

  • Wire harness or connector

  • Out of fuel

  • ECM

Comes on

DTC stored

P0138

O2 Sensor Circuit High Voltage Bank 1 Sensor 2

Short to +B in heated oxygen sensor (sensor 2) circuit.

  • Heated oxygen sensor (sensor 2)

  • Wire harness or connector

  • ECM

Comes on

DTC stored

P0139

O2 Sensor Circuit Slow Response Bank 1 Sensor 2

Heated oxygen sensor (sensor 2) information and heated oxygen sensor (sensor 1) information do not match.

  • Heated oxygen sensor (sensor 2)

  • Wire harness or connector

  • ECM

Does not come on

DTC stored

MONITOR DESCRIPTION

These DTCs are stored when the heated oxygen sensor (sensor 2) output voltage is abnormal. If there is an open or short in the heated oxygen sensor (sensor 2) circuit or the heated oxygen sensor (sensor 2) output voltage is outside of the threshold, the ECM will store a DTC.

WIRING DIAGRAM

Refer to DTC P0031.

Click here

CAUTION / NOTICE / HINT

Tip:

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

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

PROCEDURE

  1. CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO DTC P0136, P0137, P0138 AND/OR P0139)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Trouble Codes.

    5. Check for DTCs.

      Powertrain > Engine > Trouble Codes

      Result

      Result

      Proceed to

      DTC P0136, P0137, P0138 and/or P0139 are output

      A

      DTC P0136, P0137, P0138 and/or P0139 and other DTCs are output

      B
      Tip:

      If any DTCs other than DTC P0136, P0137, P0138 or P0139 are output, troubleshoot those DTCs first.

    B

    GO TO DTC CHART

    Click here

    A

  2. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

    1. Has the vehicle run out of fuel in the past?

    Result

    Proceed to

    YES

    NO
    YES

    DTC CAUSED BY RUNNING OUT OF FUEL

    NO

  3. CHECK FOR EXHAUST GAS LEAK

    1. Check the exhaust gas leaks.

      OK

      No gas leaks.

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINT

    OK

  4. INSPECT HEATED OXYGEN SENSOR (SENSOR 2)

    1. Inspect the heated oxygen sensor (sensor 2).

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE HEATED OXYGEN SENSOR (SENSOR 2)

    Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR (SENSOR 2) - ECM)

    1. Disconnect the heated oxygen sensor (sensor 2) 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

      B52-2 (HT1B) - B55-4 (HT1B)

      Always

      Below 1 Ω

      B52-3 (EX1B) - B55-21 (EX1B)

      Always

      Below 1 Ω

      B52-4 (OX1B) - B55-9 (OX1B)

      Always

      Below 1 Ω

      B52-2 (HT1B) or B55-4 (HT1B) - Body ground and other terminals

      Always

      10 kΩ or higher

      B52-3 (EX1B) or B55-21 (EX1B) - Body ground and other terminals

      Always

      10 kΩ or higher

      B52-4 (OX1B) or B55-9 (OX1B) - Body ground and other terminals

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT HEATED OXYGEN SENSOR (SENSOR 2)

    1. Check the heated oxygen sensor (sensor 2) installation condition.

      Click here

      OK

      Heated oxygen sensor (sensor 2) is installed correctly.

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE HEATED OXYGEN SENSOR (SENSOR 2)

    Click here

    OK

  7. READ VALUE USING GTS (DOWNSTREAM PROBE O2 VOLTAGE)

    1. Connect the GTS to the DLC3.

    2. Start the engine and warm it up.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine / Data List / Engine Regime and Downstream Probe O2 Voltage.

      Powertrain > Engine > Data List

      Tester Display

      Engine Regime

      Downstream Probe 02 Voltage

    5. According to the display on the GTS, read the Data List item Downstream Probe O2 Voltage while maintaining the engine speed at 2000 rpm (without load) for 120 seconds.

      OK

      The value alternates between the minimum (0 to 350 mV) and maximum (600 to 1000 mV).

    Result

    Proceed to

    OK

    NG
    OK

    CHECK FOR INTERMITTENT PROBLEMS

    Click here

    NG

  8. REPLACE HEATED OXYGEN SENSOR (SENSOR 2)

    1. Replace the heated oxygen sensor (sensor 2).

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  9. CHECK WHETHER DTC OUTPUT RECURS (DTC P0136, P0137, P0138 AND/OR P0139)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine > Clear DTCs

    5. Turn the ignition switch off and wait for a few minutes.

    6. Perform the drive test.

    7. Turn the GTS on.

    8. Enter the following menus: Powertrain / Engine / Trouble Codes.

    9. Check for DTCs.

      Powertrain > Engine > Trouble Codes

    Result

    Result

    Proceed to

    DTC P0136, P0137, P0138 and/or P0139 is output

    A

    DTCs are not output

    B
    A

    REPLACE ECM

    Click here

    B

    END