P0136 Oxygen Sensor Circuit Malfunction DTC P0137 DTC P0138 2ZR-FXE

DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)

DTC P0137 Oxygen Sensor Circuit Low Voltage (Bank 1 Sensor 2)

DTC P0138 Oxygen Sensor Circuit High Voltage (Bank 1 Sensor 2)

  1. Description

  2. Monitor description

  3. Typical enabling conditions

  4. Typical malfunction thresholds

  5. Confirmation driving pattern

  6. Wiring diagram

  7. Inspection procedure

  8. Read dtc output (dtc p0136, p0137 or p0138)

  9. Read value using intelligent tester (o2s b1s2)

  10. Inspect heated oxygen sensor (check for short)

  11. Check harness and connector (check for short)

  12. Perform active test using intelligent tester (control the injection volume)

  13. Inspect air fuel ratio sensor

  14. Inspect egr valve assembly

  15. Check exhaust gas leak

  16. Inspect heated oxygen sensor (heater resistance)

  17. Check harness and connector (heated oxygen sensor - ecm)

  18. Replace heated oxygen sensor

  19. Perform confirmation driving pattern

  20. Check whether dtc output recurs (p0136, p0137 or p0138)

  21. Replace air fuel ratio sensor

Description

HINT:

Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbons (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 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 is rich. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is lean (low voltage, i.e. below 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. higher 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.

Lexus DTC P0136  DTC P0137 DTC P0138 Description

 

DTC No. DTC Detection Condition Trouble Area
P0136* Abnormal voltage output:
  1. During active air fuel ratio control, following conditions (a) and (b) met for certain period of time (2 trip detection logic):
  2. (a) Heated oxygen sensor voltage does not decrease to below 0.21 V
  3. (b) Heated oxygen sensor voltage does not increase to higher than 0.59 V
  1. Open or short in heated oxygen sensor (sensor 2) circuit
  1. Heated oxygen sensor (sensor 2)
  2. Heated oxygen sensor (sensor 2) heater
  3. Air fuel ratio sensor (sensor 1)
  4. Gas leaks from exhaust system
  5. EGR valve assembly
P0137 Low voltage (open):
  1. During active air fuel ratio control, following conditions (a) and (b) met for certain period of time (2 trip detection logic):
  2. (a) Heated oxygen sensor voltage output below 0.21 V
  3. (b) Target air fuel ratio rich
  1. Open or short in heated oxygen sensor (sensor 2)
  1. Heated oxygen sensor (sensor 2)
  2. Heated oxygen sensor (sensor 2) heater
  3. Air fuel ratio sensor (sensor 1)
  4. Gas leak from exhaust system
  5. EGR valve assembly
P0138* High voltage (short):
  1. During active air fuel ratio control, following conditions (a) and (b) met for certain period of time (2 trip detection logic):
  2. (a) Heated oxygen sensor voltage output higher than 0.59 V
  3. (b) Target air fuel ratio lean
  1. Short in heated oxygen sensor (sensor 2) circuit
  2. Heated oxygen sensor (sensor 2)
  3. Air fuel ratio sensor (sensor 1)
  4. EGR valve assembly
  5. ECM

HINT:

*: DTC P0136 and P0138 are for Euro-OBD only.

Monitor description

Active Air Fuel Ratio Control

The ECM usually performs air fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air fuel level. This vehicle includes active air fuel ratio control in addition to regular air fuel ratio control. The ECM performs active air fuel ratio control to detect any deterioration in the three-way catalytic converter and heated oxygen sensor malfunctions (refer to the diagram below). Active air fuel ratio control is performed for approximately 30 seconds while driving with a warm engine. During active air fuel ratio control, the air fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, a DTC is stored.

Abnormal Voltage Output of Heated Oxygen Sensor (DTC P0136)

While the ECM is performing active air fuel ratio control, the air fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the heated oxygen sensor voltage does not decrease to below 0.21 V or does not increase to higher than 0.59 V during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136.

Lexus DTC P0136  DTC P0137 DTC P0138 Monitor description

 

Open or Short in Heated Oxygen Sensor Circuit (DTCs P0137 or P0138)

During active air fuel ratio control, the ECM calculates the oxygen storage capacity * of the three-way catalytic converter by forcibly regulating the air fuel ratio to become rich or lean. If the heated oxygen sensor has an open or short, or the voltage output of the sensor noticeably decreases, the oxygen storage capacity indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air fuel ratio to become rich or lean, the heated oxygen sensor output does not change. While performing active air fuel ratio control, when the target air fuel ratio is rich and the heated oxygen sensor voltage output is below 0.21 V (lean), the ECM interprets this as an abnormally low sensor output voltage and stores DTC P0137. When the target air fuel ratio is lean and the voltage output is higher than 0.59 V (rich) during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormally high, and stores DTC P0138. *: The three-way catalytic converter has the capability to store oxygen. The oxygen storage capacity and the emission purification capacity of the three-way catalytic converter are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated oxygen storage capacity value.

Lexus DTC P0136  DTC P0137 DTC P0138

Typical enabling conditions

Heated Oxygen Sensor Output Voltage (Abnormal Voltage, High Voltage and Low Voltage)
Active air fuel ratio control Performing
Active air fuel ratio control begins when all of the following conditions are met: -
Auxiliary battery voltage 11 V or higher
Engine coolant temperature 75°C (167°F) or higher
Idling OFF
Engine speed Less than 4000 rpm
Air fuel ratio sensor status Activated
Fuel system status Closed loop
Engine load 10 to 70%

Typical malfunction thresholds

Heated Oxygen Sensor Output Voltage (Abnormal Voltage)
Either of the following conditions is met: 1 or 2
1. Both of following conditions met (a) and (b)
(a) Commanded air fuel ratio 14.3 or less
(b) Heated oxygen sensor voltage 0.21 to 0.59 V
2. Both of following conditions met (c) and (d)
(c) Commanded air fuel ratio 14.9 or more
(d) Heated oxygen sensor voltage 0.21 to 0.59 V
Heated Oxygen Sensor Output Voltage (Low Voltage)
Both of following conditions met (a) and (b)
(a) Commanded air fuel ratio 14.3 or less
(b) Heated oxygen sensor voltage Below 0.21 V
Heated Oxygen Sensor Output Voltage (High Voltage)
Both of following conditions met (a) and (b)
(a) Commanded air fuel ratio 14.9 or more
(b) Heated oxygen sensor voltage Higher than 0.59 V

Confirmation driving pattern

Lexus DTC P0136  DTC P0137 DTC P0138
  1. Connect the intelligent tester to the DLC3.
  2. Turn the power switch on (IG) and turn the tester on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
  4. Turn the power switch off and wait for at least 30 seconds.
  5. Turn the power switch on (IG) and turn the tester on [A].
  6. Put the engine in inspection mode (maintenance mode) .
  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 75 to 120 km/h (47 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 [D].
  10. Read the pending DTC.

    HINT:

    1. If a pending DTC is output, the system is malfunctioning.
    2. If a pending DTC is not output, perform the following procedure.
  11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  12. Input the DTC: P0136, P0137 or P0138.
  13. Check the DTC judgment result.
    Tester Display Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    UNKNOWN
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [C] and [D] again.

Wiring diagram

Lexus DTC P0136  DTC P0137 DTC P0138 Wiring diagram

Inspection procedure

HINT:

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) and turn the tester on.
  3. Put the engine in inspection mode (maintenance mode) .
  4. Start the engine.
  5. Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
  6. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.
  7. Perform the Active Test operation with the engine in an idling.
  8. Monitor the voltage outputs of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

    HINT:

    1. Change the fuel injection volume within the range of -12.0% to +12.0%. The injection volume can be changed in fine gradations.
    2. Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
    Tester Display (Sensor) Injection Volume Status Voltage
    AFS Voltage B1S1 (Air fuel ratio) +12% Rich Less than 3.1 V
    AFS Voltage B1S1 (Air fuel ratio) -12% Lean Higher than 3.4 V
    O2S B1S2 (Heated oxygen) +12% Rich Higher than 0.55 V
    O2S B1S2 (Heated oxygen) -12% Lean Less than 0.4 V

    NOTICE:

    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 Lexus DTC P0136  DTC P0137 DTC P0138 Lexus DTC P0136  DTC P0137 DTC P0138 -
    2 Lexus DTC P0136  DTC P0137 DTC P0138 Lexus DTC P0136  DTC P0137 DTC P0138
    1. Air fuel ratio sensor
    2. Air fuel ratio sensor heater
    3. Air fuel ratio sensor circuit
    3 Lexus DTC P0136  DTC P0137 DTC P0138 Lexus DTC P0136  DTC P0137 DTC P0138
    1. Heated oxygen sensor
    2. Heated oxygen sensor heater
    3. Heated oxygen sensor circuit
    4. Exhaust gas leaks
    4 Lexus DTC P0136  DTC P0137 DTC P0138 Lexus DTC P0136  DTC P0137 DTC P0138
    1. Fuel pressure
    2. Exhaust gas leaks (Air fuel ratio extremely lean or rich)
    1. Following the Control the Injection Volume procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
    2. To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.

NOTICE:

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

HINT:

  1. If the OX1B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 will be set.
  2. Sensor 1 refers to the sensor closest to the engine assembly.
  3. Sensor 2 refers to the sensor farthest away from the engine assembly.
  4. 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.

1.READ DTC OUTPUT (DTC P0136, P0137 OR P0138)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

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

  1. Read the DTCs.

    Result
    Result Proceed to
    DTC P0138 is output A
    DTC P0137 is output B
    DTC P0136 is output C
    P0136, P0137 or P0138 and other DTCs are output D
  B  
Go to step 11
 
  C  
Go to step 7
 
  D  
GO TO DTC CHART
 
OK  
   

2.READ VALUE USING INTELLIGENT TESTER (O2S B1S2)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine.

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

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

    Result
    Result Proceed to
    1.0 V or higher A
    Below 1.0 V B
  B  
Go to step 5
 
OK  
   

3.INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)

Lexus DTC P0136  DTC P0137 DTC P0138 Disconnect the heated oxygen sensor connector.

  1. Disconnect the heated oxygen sensor connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    2 (+B) - 4 (E2) Always 10 k? or higher
    2 (+B) - 3 (OX1B) Always 10 k? or higher
    Text in Illustration
    *a Component without harness connected (Heated Oxygen Sensor (Sensor 2))
  NG  
REPLACE HEATED OXYGEN SENSOR
 
OK  
   

4.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)
  1. Turn the power switch off and wait for 5 minutes or more.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    D27-41 (HT1B) - D27-125 (OX1B) Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
REPLACE ECM

5.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine and warm it up.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.

  1. 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.

    HINT:

    1. Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine graduations within this range.
    2. The air fuel ratio sensor is displayed as AFS Voltage B1S1, and the heated oxygen sensor is displayed as O2S B1S2 on the tester.
    3. 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.
    4. 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) Alternates between higher and below 3.3 V OK
    Remains at higher than 3.3 V NG
    Remains at below 3.3 V NG

    HINT:

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

    Lexus DTC P0136  DTC P0137 DTC P0138 oxygen sensor voltage (O2S B1S2)
  NG  
Go to step 19
 
OK  
   

6.INSPECT AIR FUEL RATIO SENSOR

HINT:

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.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs .

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.

  1. Drive the vehicle at 75 km/h (47 mph) or more for 10 minutes or more.

    CAUTION:

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

  1. Stop the vehicle.

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

  1. Drive the vehicle at 75 km/h (47 mph) or more and decelerate the vehicle for 5 seconds or more. Perform this 3 times.

    CAUTION:

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

    Lexus DTC P0136  DTC P0137 DTC P0138 Read the value of the air fuel ratio sensor current while the fuel-cut operation is being performed.
  1. Read the value of the air fuel ratio sensor current while the fuel-cut operation is being performed.

    Standard current:

    Below 2.2 mA

    HINT:

    1. To measure the air fuel ratio sensor current precisely, perform the fuel-cut operation as long as possible.
    2. If it is difficult to measure the air fuel ratio sensor current, use the snapshot function of the intelligent tester.
  OK  
Go to step 14
 
  NG  
Go to step 19
 

7.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine and warm it up.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / O2S B1S2.

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

    HINT:

    1. Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine graduations within this range.
    2. 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.

    Standard:

    Fluctuates between 0.4 V or less and 0.55 V or higher.

  NG  
Go to step 11
 
OK  
   

8.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine and warm it up.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.

  1. 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.

    HINT:

    1. Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine graduations within this range.
    2. The air fuel ratio sensor is displayed as AFS Voltage B1S1, and the heated oxygen sensor is displayed as O2S B1S2 on the tester.
    3. 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.
    4. 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) Alternates between higher and below 3.3 V OK
    Remains at higher than 3.3 V NG
    Remains at below 3.3 V NG

    HINT:

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

    Lexus DTC P0136  DTC P0137 DTC P0138 oxygen sensor voltage.
  NG  
Go to step 19
 
OK  
   

9.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

  1. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or more.

    HINT:

    The A/C switch and all accessory switches should be off.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.

  1. Confirm that the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

    HINT:

    1. Do not leave the EGR valve open for 10 seconds or more during the Active Test.
    2. Be sure to return the EGR valve to step 0 when the Active Test is completed.
    3. Do not open the EGR valve 30 steps or more during the Active Test.

    OK:

    MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

    Standard:

    - EGR Step Position (Active Test)
    0 Steps 0 to 30 Steps
    Idling condition Steady idling Idling changes from steady to rough idling or stalls
    MAP (Data List) MAP value is 20 to 40 kPa (150 to 300 mmHg) (EGR valve is fully closed) MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

    HINT:

    During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

    Result
    Result Proceed to
    Outside of standard range A
    Within standard range B
  B  
CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO AND REPAIR CAUSE (FUEL INJECTOR ASSEMBLY, FUEL PRESSURE, GAS LEAK FROM SYSTEM)
 
OK  
   

10.INSPECT EGR VALVE ASSEMBLY
  1. Remove the EGR valve assembly .

  1. Check if the EGR valve is stuck open.

    OK:

    EGR valve is tightly closed.

  NG  
REPLACE EGR VALVE ASSEMBLY
 
OK  
   
CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO AND REPAIR CAUSE (FUEL INJECTOR ASSEMBLY, FUEL PRESSURE, GAS LEAK FROM SYSTEM)

11.CHECK EXHAUST GAS LEAK
  1. Check for exhaust gas leaks.

OK:

No gas leaks.

  NG  
REPAIR OR REPLACE EXHAUST GAS LEAK POINT
 
OK  
   

12.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
  1. Inspect the heated oxygen sensor .

  NG  
REPLACE HEATED OXYGEN SENSOR
 
OK  
   

13.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
  1. Disconnect the heated oxygen sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    D9-1 (HT1B) - D27-41 (HT1B) Always Below 1 ?
    D9-3 (OX1B) - D27-125 (OX1B) Always Below 1 ?
    D9-4 (E2) - D27-102 (O1B-) Always Below 1 ?
    D9-1 (HT1B) or D27-41 (HT1B) - Body ground Always 10 k? or higher
    D9-3 (OX1B) or D27-125 (OX1B) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

14.REPLACE HEATED OXYGEN SENSOR
  1. Replace the heated oxygen sensor .

NEXT  
   

15.PERFORM CONFIRMATION DRIVING PATTERN
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs .

  1. Turn the power switch off and wait for at least 30 seconds.

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

NEXT  
   

16.CHECK WHETHER DTC OUTPUT RECURS (P0136, P0137 OR P0138)
  1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  1. Input the DTCs: P0136, P0137 or P0138.

  1. Check the DTC judgment result is NORMAL. If it is INCOMPLETE, perform the drive pattern adding the vehicle speed.

    Result
    Result Proceed to
    ABNORMAL (DTC P0136, P0137 or P0138 is output) A
    NORMAL (DTC is not output) B
  B  
END
 
OK  
   

17.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

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

    HINT:

    The A/C switch and all accessory switches should be off.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.

  1. Confirm that the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

    HINT:

    1. Do not leave the EGR valve open for 10 seconds or more during the Active Test.
    2. Be sure to return the EGR valve to step 0 when the Active Test is completed.
    3. Do not open the EGR valve 30 steps or more during the Active Test.

    OK:

    MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

    Standard:

    - EGR Step Position (Active Test)
    0 Steps 0 to 30 Steps
    Idling condition Steady idling Idling changes from steady to rough idling or stalls
    MAP (Data List) MAP value is 20 to 40 kPa (150 to 300 mmHg) (EGR valve is fully closed) MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

    HINT:

    During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

    Result
    Result Proceed to
    Outside of standard range A
    Within standard range B
  B  
REPLACE AIR FUEL RATIO SENSOR
 
OK  
   

18.INSPECT EGR VALVE ASSEMBLY
  1. Remove the EGR valve assembly .

  1. Check if the EGR valve is stuck open.

    OK:

    EGR valve is tightly closed.

  NG  
REPLACE EGR VALVE ASSEMBLY
 
OK  
   
REPLACE AIR FUEL RATIO SENSOR

19.REPLACE AIR FUEL RATIO SENSOR
  1. Replace the air fuel ratio sensor .

NEXT  
   

20.PERFORM CONFIRMATION DRIVING PATTERN
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Clear the DTCs .

  1. Turn the power switch off and wait for at least 30 seconds.

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

NEXT  
   

21.CHECK WHETHER DTC OUTPUT RECURS (DTC P0136 OR P0138)
  1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  1. Input the DTCs: P0136 or P0138.

  1. Check the DTC judgment result is NORMAL. If it is INCOMPLETE, perform the driving pattern again and increase the vehicle speed.

    Result
    Result Proceed to
    ABNORMAL (DTC P0136 or P0138 is output) A
    NORMAL (DTC is not output) B
  B  
END
 
OK  
   

22.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the tester on.

  1. Put the engine in inspection mode (maintenance mode) .

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

    HINT:

    The A/C switch and all accessory switches should be off.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.

  1. Confirm that the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

    HINT:

    1. Do not leave the EGR valve open for 10 seconds or more during the Active Test.
    2. Be sure to return the EGR valve to step 0 when the Active Test is completed.
    3. Do not open the EGR valve 30 steps or more during the Active Test.

    OK:

    MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.

    Standard:

    - EGR Step Position (Active Test)
    0 Steps 0 to 30 Steps
    Idling condition Steady idling Idling changes from steady to rough idling or stalls
    MAP (Data List) MAP value is 20 to 40 kPa (150 to 300 mmHg) (EGR valve is fully closed) MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed

    HINT:

    During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

    Result
    Result Proceed to
    Outside of standard range A
    Within standard range B
  B  
REPLACE HEATED OXYGEN SENSOR
 
OK  
   

23.INSPECT EGR VALVE ASSEMBLY
  1. Remove the EGR valve assembly .

  1. Check if the EGR valve is stuck open.

    OK:

    EGR valve is tightly closed.

  NG  
REPLACE EGR VALVE ASSEMBLY
 
OK  
   
REPLACE HEATED OXYGEN SENSOR