SFI SYSTEM, Diagnostic DTC:P0136, P0137, P0138, P0156, P0157, P0158

DTC Code DTC Name
P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0137 Oxygen Sensor Circuit Low Voltage (Bank 1 Sensor 2)
P0138 Oxygen Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0156 Oxygen Sensor Circuit Malfunction (Bank 2 Sensor 2)
P0157 Oxygen Sensor Circuit Low Voltage (Bank 2 Sensor 2)
P0158 Oxygen Sensor Circuit High Voltage (Bank 2 Sensor 2)

DESCRIPTION

Tech Tips

Sensor 2 refers to the sensor mounted behind the three-way catalytic converter and located far from the engine assembly.

A three-way catalytic converter is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (HOx) into less harmful substances. To allow the three-way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio. For helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor is used.

The heated oxygen sensor 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 becomes rich. The heated oxygen sensor informs 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 informs 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 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 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 is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.

A01CAIUE16
DTC No. DTC Detection Condition Trouble Area

P0136

P0156

  • Abnormal voltage output:

    During active air fuel ratio control, following conditions (a) and (b) are met for a certain period of time (2 trip detection logic):

    (a) Heated oxygen sensor voltage does not decrease to less than 0.2 V

    (b) Heated oxygen sensor voltage does not increase to more than 0.6 V


  • Low impedance:

    Sensor impedance less than 5 Ω for more than 30 seconds when ECM presumes sensor to being warmed up and operating normally (2 trip detection logic)

  • Open or short in heated oxygen sensor (bank 1, 2 sensor 2) circuit

  • Heated oxygen sensor (bank 1, 2 sensor 2)

  • Heated oxygen sensor heater (bank 1, 2 sensor 2)

  • Air fuel ratio sensor (bank 1, 2 sensor 1)

  • Gas leaks from exhaust system

P0137

P0157

  • Low voltage (open):

    During active air fuel ratio control, following conditions (a) and (b) are met for a certain period of time (2 trip detection logic):

    (a) Heated oxygen sensor voltage output less than 0.21 V

    (b) Target air fuel ratio rich


  • High impedance:

    Sensor impedance 15 kΩ or more for more than 90 seconds when ECM presumes sensor to being warmed up and operating normally (2 trip detection logic)

  • Open in heated oxygen sensor (bank 1, 2 sensor 2) circuit

  • Heated oxygen sensor (bank 1, 2 sensor 2)

  • Heated oxygen sensor heater (bank 1, 2 sensor 2)

  • Gas leaks from exhaust system

P0138

P0158

  • High voltage (short):

    During active air fuel ratio control, following conditions (a) and (b) are met for a certain period of time (2 trip detection logic):

    (a) Heated oxygen sensor voltage output 0.59 V or more

    (b) Target air fuel ratio lean


  • Extremely high voltage (short):

    Heated oxygen sensor voltage output exceeds 1.2 V for more than 30 seconds (2 trip detection logic)

  • Short in heated oxygen sensor (bank 1, 2 sensor 2) circuit

  • Heated oxygen sensor (bank 1, 2 sensor 2)

  • ECM internal circuit malfunction

WIRING DIAGRAM

A01CD3NE01

CONFIRMATION DRIVING PATTERN

A01CDSEE54

  1. Connect the intelligent tester to the DLC3.

  2. Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more (Procedure "A").

  3. Drive the vehicle at 60 to 120 km/h (40 to 75 mph) for 10 minutes or more (Procedure "B").

  4. Drive the vehicle at 60 km/h (40 mph) or more and decelerate the vehicle for 5 seconds or more. Perform this 3 times (Procedure "C").

  5. Turn the tester on.

  6. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

  7. Input DTCs: P0136, P0137, P0138, P0156, P0157 and P0158.

  8. Check that DTC Monitor is NORMAL. If DTC Monitor is INCOMPLETE, perform the driving pattern adding the vehicle speed and using the second gear to decelerate the vehicle.

INSPECTION PROCEDURE

Tech Tips

Intelligent tester only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the air fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the intelligent tester.


  1. Connect the intelligent tester to the DLC3.

  2. Start the engine and turn the tester on.

  3. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

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

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

  6. Monitor the voltage outputs of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) 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%.

    • Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

    Tester Display (Sensor) Injection Volume Status Voltage

    AFS Voltage B1S1 or AFS Voltage B2S1

    (Air fuel ratio)

    		 12.5% Rich Less than 3.1

    AFS Voltage B1S1 or AFS Voltage B2S1

    (Air fuel ratio)

    		 -12.5% Lean More than 3.4

    O2S B1S2 or O2S B2S2

    (Heated oxygen)

    		 12.5% Rich More than 0.55

    O2S B1S2 or O2S B2S2

    (Heated oxygen)

    		 -12.5% Lean Less than 0.4

    Note

    The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.

    Case Air Fuel Ratio Sensor (Sensor 1) Output Voltage Heated Oxygen Sensor (Sensor 2) Output Voltage Main Suspected Trouble Area
    1 A01CFAQE13 A01CBBDE08 A01CFAQE13 A01CET8E06 -
    2 A01CFAQE13 A01CBU2E01 A01CFAQE13 A01CET8E06

    • Air fuel ratio sensor

    • Air fuel ratio sensor heater

    • Air fuel ratio sensor circuit
    3 A01CFAQE13 A01CBBDE08 A01CFAQE13 A01CBU2E01

    • Heated oxygen sensor

    • Heated oxygen sensor heater

    • Heated oxygen sensor circuit

    • Exhaust gas leaks
    4 A01CFAQE13 A01CBU2E01 A01CFAQE13 A01CBU2E01

    • Fuel pressure

    • Exhaust gas leaks

      (Air fuel ratio extremely lean or rich)

    • Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.

    • To display the graph, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

Tech Tips


  • Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

  • If the OX1B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 will be set.

  • If the OX2B wire from the ECM connector is short-circuited to the +B wire, DTC P0156 will be set.

PROCEDURE


  1. READ DTC OUTPUT (DTC P0136, P0137, P0138, P0156, P0157 or P0158)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read the DTCs.

      Result
      Result Proceed to
      DTC P0138 or P0158 is output A
      DTC P0137 or P0157 is output B
      DTC P0136 or P0156 is output C

    B

    INSPECT FOR EXHAUST GAS LEAK Click here

    C

    READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR) Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Enter the following menus: Powertrain / Engine / Data List / A/F Control System / O2S B1S2 or O2S B2S2.

    4. Allow the engine to idle.

    5. Read the heated oxygen sensor output voltage while idling.

      Result
      Tester Display Result Proceed to
      O2S B1S2 or O2S B2S2 1.0 V or more A
      Less than 1.0 V B

    B

    CHECK AIR FUEL RATIO SENSOR Click here

    A

  3. INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)


    1. A01CEXPE03

      Disconnect the heated oxygen sensor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (+B) - 3 (E2) Always 10 kΩ or higher
      1 (+B) - 4 (OX1B) Always 10 kΩ or higher
      2 (+B) - 4 (E2) Always 10 kΩ or higher
      2 (+B) - 3 (OX2B) Always 10 kΩ or higher

    3. Reconnect the heated oxygen sensor connector.


    NG

    REPLACE HEATED OXYGEN SENSOR Click here

    OK

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


    1. Turn the engine switch off and wait for 5 minutes.

    2. Disconnect the ECM connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D1-48 (HT1B) - D1-88 (OX1B) Always 10 kΩ or higher
      D1-47 (HT2B) - D1-87 (OX2B) Always 10 kΩ or higher

    4. Reconnect the ECM connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATED OXYGEN SENSOR - ECM)

    OK

    REPLACE ECM Click here

  5. CHECK AIR FUEL RATIO SENSOR

    Tech Tips

    This air fuel ratio sensor test is to check the air fuel ratio sensor current during the fuel-cut operation. When the sensor is normal, the sensor current will indicate below 3.0 mA in this test.


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine / DTC / Clear.

    5. Clear the DTCs.

    6. Drive the vehicle by the driving pattern as listed below:


      1. Warm up the engine.

      2. Drive the vehicle at 60 km/h (40 mph) or more for 10 minutes or more.

      3. Stop the vehicle.

      4. Accelerate the vehicle up to 60 km/h (40 mph) or more and then decelerate for 5 seconds or more. Repeat this process at least 3 times.

        A01CAO6E12

    7. Enter the following menus: Powertrain / Engine / Data List / A/F Control System / AFS Voltage B1S1 and AFS Voltage B2S1.

    8. Read the value of the air fuel ratio sensor current while the fuel-cut operation is being performed.

      Standard current
      Less than 3.0 mA

      Tech Tips


      • To measure the air fuel ratio sensor current precisely, perform the fuel-cut operation as long as possible.

      • If it is difficult to measure the air fuel ratio sensor current, use the snapshot function of the intelligent tester.

      Result
      Result Proceed to
      Within standard range A
      Outside standard range B

    A

    REPLACE HEATED OXYGEN SENSOR Click here

    B

    REPLACE AIR FUEL RATIO SENSOR Click here

  6. READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

    3. Start the engine.

    4. Enter the following menus: Powertrain / Engine / Data List / A/F Control System / O2S B1S2 or O2S B2S2.

    5. After warming up the engine, run the engine at an engine speed of 2500 rpm for 3 minutes.

    6. Read the output voltage of the heated oxygen sensor when the engine speed is suddenly increased.

      Tech Tips

      Quickly accelerate the engine to 4000 rpm 3 times using the accelerator pedal.

      Standard
      Fluctuates between 0.4 V or less and 0.55 V or more.

    NG

    INSPECT FOR EXHAUST GAS LEAK Click here

    OK

  7. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION VOLUME)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine and turn the tester on.

    3. Warm up the engine.

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

    5. Change the fuel injection volume using the tester, and monitor the voltage output of air fuel ratio and heated oxygen sensors 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 air fuel ratio sensor is displayed as AFS Voltage B1S1 or AFS Voltage B2S1, and the heated oxygen sensor is displayed as O2S B1S2 or O2S B2S2, on the intelligent tester.

      Result
      Tester Display (Sensor) Voltage Variation Proceed to

      AFS Voltage B1S1 (Air fuel ratio)

      AFS Voltage B2S1 (Air fuel ratio)

      		 Alternates between more and less than 3.3 V OK

      AFS Voltage B1S1 (Air fuel ratio)

      AFS Voltage B2S1 (Air fuel ratio)

      		 Remains at more than 3.3 V NG

      AFS Voltage B1S1 (Air fuel ratio)

      AFS Voltage B2S1 (Air fuel ratio)

      		 Remains at less than 3.3 V NG

      Tech Tips

      A normal heated oxygen sensor voltage (O2S B1S2 or O2S B2S2) reacts in accordance with increases and decreases in fuel injection volumes. When the air fuel ratio sensor voltage remains at either less or more than 3.3 V despite the heated oxygen sensor indicating a normal reaction, the air fuel ratio sensor is malfunctioning.

      A01CBY8E36

    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

    CHECK ENGINE TO DETERMINE CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO Click here

  8. INSPECT FOR EXHAUST GAS LEAK


    1. Inspect for exhaust gas leak from the exhaust manifold sub-assembly and exhaust pipes.

      OK
      No gas leaks.

    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINT

    OK

  9. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. Inspect the heated oxygen sensor Click here.


    NG

    REPLACE HEATED OXYGEN SENSOR Click here

    OK

  10. CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)


    1. Disconnect the heated oxygen sensor connector.

      A01CCYTE01

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G37-1 (+B) - Body ground Engine switch on (IG) 11 to 14 V
      D24-2 (+B) - Body ground Engine switch on (IG) 11 to 14 V

    4. Reconnect the heated oxygen sensor connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATED OXYGEN SENSOR - EFI MAIN RELAY)

    OK

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


    1. Disconnect the heated oxygen sensor connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      G37-2 (HT1B) - D1-48 (HT1B) Always Below 1 Ω
      G37-4 (OX1B) - D1-88 (OX1B) Always Below 1 Ω
      G37-3 (E2) - D1-65 (EX1B) Always Below 1 Ω
      D24-1 (HT2B) - D1-47 (HT2B) Always Below 1 Ω
      D24-3 (OX2B) - D1-87 (OX2B) Always Below 1 Ω
      D24-4 (E2) - D1-64 (EX2B) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      G37-2 (HT1B) or D1-48 (HT1B) - Body ground Always 10 kΩ or higher
      G37-4 (OX1B) or D1-88 (OX1B) - Body ground Always 10 kΩ or higher
      D24-1 (HT2B) or D1-47 (HT2B) - Body ground Always 10 kΩ or higher
      D24-3 (OX2B) or D1-87 (OX2B) - Body ground Always 10 kΩ or higher

    4. Reconnect the heated oxygen sensor connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (HEATED OXYGEN SENSOR - ECM)

    OK

  12. REPLACE HEATED OXYGEN SENSOR


    1. Replace the heated oxygen sensor Click here.


    NEXT

  13. PERFORM CONFIRMATION DRIVING PATTERN


    1. Perform confirmation driving pattern.


    NEXT

  14. CHECK WHETHER DTC OUTPUT RECURS (DTC P0136, P0137, P0138, P0156, P0157 OR P0158)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    5. Input DTC: P0136, P0137, P0138, P0156, P0157 or P0158.

      Check the DTC Monitor is NORMAL. If DTC Monitor is INCOMPLETE, perform the driving pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B

    B

    END

    A

    REPLACE AIR FUEL RATIO SENSOR Click here

  15. REPLACE AIR FUEL RATIO SENSOR


    1. Replace the air fuel ratio sensor Click here.


    NEXT

  16. PERFORM CONFIRMATION DRIVING PATTERN


    1. Perform confirmation driving pattern.


    NEXT

  17. CHECK WHETHER DTC OUTPUT RECURS (DTC P0136, P0137, P0138, P0156, P0157 OR P0158)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

    5. Input DTC: P0136, P0137, P0138, P0156, P0157 or P0158.

      Check the DTC Monitor is NORMAL. If DTC Monitor is INCOMPLETE, perform the driving pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B

    B

    END

    A

    REPLACE HEATED OXYGEN SENSOR Click here