SFI SYSTEM (w/o EGR 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 oxides of nitrogen (NOx) 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.

A01NGZ1E01
DTC No. DTC Detection Condition Trouble Area

P0136

P0156

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 0.21 V

(b) Heated oxygen sensor voltage does not increase to more than 0.59 V

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

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

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

  • Gas leaks from exhaust system

  • Fuel pressure

  • Fuel injector assembly

  • PCV valve and hose

  • Intake system

P0137

P0157

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

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

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

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

  • Gas leaks from exhaust system

P0138

P0158

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 more than 0.59 V

(b) Target air fuel ratio lean

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

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

  • ECM

CONFIRMATION DRIVING PATTERN

A01NCWWE26

  1. Connect the intelligent tester to the DLC3.

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

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Click here.

  4. Turn the power switch off and wait for 30 seconds.

  5. Turn the power switch on (IG) and turn the tester on [A].

  6. Put the engine in inspection mode Click here.

  7. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [B].

  8. Drive the vehicle at 60 to 120 km/h (37 to 75 mph) for 10 minutes or more [C].

    CAUTION:

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

  9. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending [D].

  10. Read the pending DTC.

  11. If a pending DTC is output, the system is malfunctioning.

    Tech Tips

    If a pending DTC is not output, perform the following procedure.

  12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

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

  14. Check the DTC judgment result.

    Tester Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

    Tech Tips


    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform step [C] and check the DTC judgment result again.

WIRING DIAGRAM

A01NEENE06

INSPECTION PROCEDURE

Tech Tips

Malfunctioning areas can be identified by performing the Control the Injection Volume function provided in the Active Test. The Control the Injection Volume 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 operation using the intelligent tester.


  1. Connect the intelligent tester to the DLC3.

  2. Turn the power switch on (IG).

  3. Turn the tester on.

  4. Put the engine in inspection mode Click here.

  5. Start the engine.

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

    Tech Tips

    During charging control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, warm up the engine after charging control has completed.

  7. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

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

  9. Monitor the output voltages 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


  • Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.

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

Tester Display

(Sensor)

 Injection Volume Status Voltage

AFS Voltage B1S1

AFS Voltage B2S1

(Air fuel ratio)

 +12% Rich Below 3.1 V
-12% Lean Higher than 3.4 V

O2S B1S2

O2S B2S2

(Heated oxygen)

 +12% Rich Higher than 0.55 V
-12% Lean Below 0.4 V

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 A01NER4E05 A01NEU5E08 A01NER4E05 A01NGBEE06 -
2 A01NER4E05 A01NCSNE01 A01NER4E05 A01NGBEE06

  • Air fuel ratio sensor

  • Air fuel ratio sensor heater

  • Air fuel ratio sensor circuit
3 A01NER4E05 A01NEU5E08 A01NER4E05 A01NCSNE01

  • Heated oxygen sensor

  • Heated oxygen sensor heater

  • Heated oxygen sensor circuit
4 A01NER4E05 A01NCSNE01 A01NER4E05 A01NCSNE01

  • Fuel injector assembly

  • Fuel pressure

  • Gas leak from exhaust system (Air fuel ratio extremely rich or lean)

Note

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

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 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.

  • 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 OUTPUT DTC (DTC P0136, P0137, P0138, P0156, P0157 OR P0158)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

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

    5. 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
      DTC P0136, P0137, P0138, P0156, P0157 or P0158 and other DTCs are output D

      Tech Tips

      If any DTCs other than P0136, P0137, P0138, P0156, P0157 and P0158 are output, troubleshoot those DTCs first.


    B

    INSPECT FOR EXHAUST GAS LEAK Click here

    C

    PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME) Click here

    D

    GO TO DTC CHART 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 power switch on (IG).

    3. Turn the tester on.

    4. Put the engine in inspection mode Click here.

    5. Start the engine.

    6. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / O2S B1S2 or O2S B2S2.

    7. Allow the engine to idle.

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

      Result
      Result Proceed to
      1.0 V or more A
      Less than 1.0 V B

    B

    PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION VOLUME) Click here

    A

  3. INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)


    1. A01NE5CE07
      Text in Illustration
      *1

      Component without harness connected

      (Heated Oxygen Sensor)
      *2 Bank 1
      *3 Bank 2

      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 (CHECK FOR SHORT)


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

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      D1-18 (HT1B) - D1-130 (OX1B) Always 10 kΩ or higher
      D1-17 (HT2B) - D1-98 (OX2B) Always 10 kΩ or higher

    4. Reconnect the ECM connector.


    NG

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

    OK

    REPLACE ECM Click here

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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Put the engine in inspection mode Click here.

    5. Warm up the engine.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.

    7. Change the fuel injection volume using the tester, and monitoring the voltage output of air fuel ratio and heated oxygen sensors displayed on the tester.

      Tech Tips


      • Change the fuel injection volume within the range of - 12% to +12%. The injection volume can be changed in fine gradations within this range.

      • 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 tester.

      • 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.

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

      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
      Remains at more than 3.3 V NG
      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.

      A01NE8JE22

    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

  6. 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. When the sensor is normal, the sensor current will indicate below 2.2 mA in this test.


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Drive the vehicle by the drive pattern as listed below:


      1. Put the engine in inspection mode Click here.

      2. Warm up the engine until the engine coolant temperature reaches 75°C (167°F) or more.

      3. Drive the vehicle at 60 km/h (37 mph) or more with the shift lever in S, select the S2 range, and decelerate the vehicle for 5 seconds or more.

      4. Repeat the deceleration above at least 3 times.

        A01NFRWE34

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / AFS Current B1S1 and AFS Current B2S1.

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

      Standard Current
      Less than 2.2 mA

      Tech Tips


      • To measure the air fuel ration 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.


    OK

    REPLACE HEATED OXYGEN SENSOR Click here

    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Put the engine in inspection mode Click here.

    5. Warm up the engine.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test/ Control the Injection Volume.

    7. Change the fuel injection volume using the tester, and monitoring the voltage output of heated oxygen sensor displayed on the tester.

      Tech Tips


      • Change the fuel injection volume within the range of - 12% to +12%. The injection volume can be changed in fine gradations within this range.

      • The heated oxygen sensor is displayed as O2S B1S2 or O2S B2S2 on the tester.

      • The heated oxygen sensor has a maximum output delay of approximately 20 seconds.

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

    NG

    INSPECT FOR EXHAUST GAS LEAK Click here

    OK

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


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Put the engine in inspection mode Click here.

    5. Warm up the engine.

    6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.

    7. Change the fuel injection volume using the tester, and monitoring the voltage output of air fuel ratio and heated oxygen sensors displayed on the tester.

      Tech Tips


      • Change the fuel injection volume within the range of - 12% to +12%. The injection volume can be changed in fine gradations within this range.

      • 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 tester.

      • 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.

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

      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
      Remains at more than 3.3 V NG
      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.

      A01NE8JE22

    NG

    REPLACE AIR FUEL RATIO SENSOR Click here

    OK

    CHECK AND REPLACE EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (INJECTOR, FUEL PRESSURE, GAS LEAK, ETC.) Click here

  9. INSPECT FOR EXHAUST GAS LEAK


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

      OK
      No gas leaks.

    NG

    REPAIR OR REPLACE EXHAUST GAS LEAK POINT

    OK

  10. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    1. Inspect the heated oxygen sensor Click here.


    NG

    REPLACE HEATED OXYGEN SENSOR Click here

    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
      S1-2 (HT1B) - D1-18 (HT1B) Always Below 1 Ω
      S1-4 (OX1B) - D1-130 (OX1B) Always Below 1 Ω
      S1-3 (E2) - D1-129 (EX1B) Always Below 1 Ω
      D36-1 (HT2B) - D1-17 (HT2B) Always Below 1 Ω
      D36-3 (OX2B) - D1-98 (OX2B) Always Below 1 Ω
      D36-4 (E2) - D1-97 (EX2B) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      S1-2 (HT1B) or D1-18 (HT1B) - Body ground Always 10 kΩ or higher
      S1-4 (OX1B) or D1-130 (OX1B) - Body ground Always 10 kΩ or higher
      D36-1 (HT2B) or D1-17 (HT2B) - Body ground Always 10 kΩ or higher
      D36-3 (OX2B) or D1-98 (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. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTC Click here.

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

    6. Turn the power switch on (IG) and turn the tester on.

    7. Put the engine in inspection mode Click here.

    8. Start the engine and warm it up.

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


    NEXT

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


    1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

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

    3. Check the STATUS is NORMAL. If STATUS is INCOMPLETE, perform the driving pattern adding the vehicle speed.

      Result
      Result Proceed to

      ABNORMAL

      (DTC P0136, P00137, P0138, P0156, P0157 or P0158 is output)

      		 A

      NORMAL

      (DTC is not output)

      		 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. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester on.

    4. Clear the DTC Click here.

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

    6. Turn the power switch on (IG) and turn the tester on.

    7. Put the engine in inspection mode Click here.

    8. Start the engine and warm it up.

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


    NEXT

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


    1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    2. Input the DTC: P0136, P0138, P0156 or P0158.

    3. Check the STATUS is NORMAL. If STATUS is INCOMPLETE, perform the driving pattern adding the vehicle speed.

      Result
      Result Proceed to

      ABNORMAL

      (DTC P0136, P0138, P0156 or P0158 is output)

      		 A

      NORMAL

      (DTC is not output)

      		 B

    B

    END

    A

    REPLACE HEATED OXYGEN SENSOR Click here