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)

for Preparation Click here


DESCRIPTION

HINT:
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, hydrocarbons, and nitrogen oxides 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 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. 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.

A112653E01


DTC No.
DTC Detection Condition
Trouble Area
P0136
  1. Abnormal voltage output:
    During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2-trip detection logic):
    1. (a) Heated oxygen sensor voltage does not decrease to less than 0.21 V
    1. (b) Heated oxygen sensor voltage does not increase to more than 0.70 V
  1. Open or short in heated oxygen sensor (sensor 2) circuit
  2. Heated oxygen sensor (sensor 2)
  3. Air fuel ratio sensor (sensor 1)
  4. Gas leak from exhaust system
  5. EGR valve assembly
P0137
  1. Low voltage (open):
    During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2-trip detection logic):
    1. (a) Heated oxygen sensor voltage output less than 0.21 V
    1. (b) Target air fuel ratio rich
  1. Open in heated oxygen sensor (sensor 2) circuit
  2. Heated oxygen sensor (sensor 2)
  3. Gas leak from exhaust system
  4. EGR valve assembly
P0138
  1. High voltage (short):
    During active air fuel ratio control, the following conditions (a) and (b) are met for certain period of time (2-trip detection logic):
    1. (a) Heated oxygen sensor voltage output 0.70 V or more
    1. (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

WIRING DIAGRAM


A201211E05


CONFIRMATION DRIVING PATTERN

HINT:
  1. This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" procedure of the following diagnostic troubleshooting procedure.
  2. Performing this confirmation pattern will activate the heated oxygen sensor monitor. (The catalyst monitor is performed simultaneously.) This is very useful for verifying the completion of the repair.


A115372E98

  1. Connect an 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 / Clear.
  5. Clear DTCs (Click here).
  6. Switch the ECM from normal mode to check mode (Click here).
  7. Enter the following menus: Powertrain / Engine and ECT / Data List / O2S (A/FS) Monitor.
  8. Check that the item O2S (A/FS) Monitor displays Incmpl (Incomplete).
  9. Start the engine and warm it up (Proceed to "A").
  10. Drive the vehicle at between 90 km/h and 110 km/h (56 mph and 68 mph) for at least 10 minutes (Proceed to "B").
  11. Note the state of the Data List items. Those items will change to Compl (Complete) as the O2 Sensor monitor operates.
  12. Enter the following menus: Powertrain / Engine and ECT / DTC and check if any DTCs (any pending DTCs) are set.

HINT:
If the item O2S (A/FS) Monitor does not change to Compl (Complete), and any pending DTCs fail to set, extend the driving time.


INSPECTION PROCEDURE

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

HINT:
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 (A/F) sensor, Heated Oxygen (HO2) 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 and ECT / 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 output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

HINT:
  1. The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
  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
(A/F)
+25%
Rich
Less than 3.1 V
AFS Voltage B1S1
(A/F)
-12.5%
Lean
More than 3.4 V
O2S B1S2
(HO2)
+25%
Rich
 More than 0.55 V
O2S B1S2
(HO2)
-12.5%
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
A/F Sensor (Sensor 1) Output Voltage
HO2 Sensor (Sensor 2) Output Voltage
Main Suspected Trouble Area
1
A150787E01
A151324E04
A150787E01
A150788E01
-
2
A150787E01
A150790E01
A150787E01
A150788E01
  1. A/F sensor
  2. A/F sensor heater
  3. A/F sensor circuit
3
A150787E01
A151324E04
A150787E01
A150790E01
  1. HO2 sensor
  2. HO2 sensor heater
  3. HO2 sensor circuit
4
A150787E01
A150790E01
A150787E01
A150790E01
  1. Injector
  2. Fuel pressure
  3. Gas leak from exhaust system (Air-fuel ratio extremely rich or lean)
  1. Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
  2. To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2; then press the View button.

HINT:
  1. Read freeze frame data using an 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.

1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P0136, P0137 OR P0138)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the DTC.

Result 
Result
Proceed to
P0136, P0137 or P0138
A
P0136, P0137 or P0138 and other DTCs
B


B
GO TO DTC CHART (Click here)
A


2.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (OPERATE EGR VALVE)

  1. Connect the intelligent tester to the DLC3.

  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. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

  1. Check the MAP in Data List and the idling condition while performing Active Test.

    OK:
    MAP and idling condition change in response to EGR step position.


Standard:

-
EGR Step Position (Active Test)
0 Steps
0 to 30 Steps
30 to 40 Steps or Higher
Idling condition
Steady idling
Engine changes from steady to rough idling
Engine changes from rough idling to engine stall
MAP value
(Data List)
28 to 48 kPa
(EGR valve is fully closed)
MAP value is at least +10 to 15 kPa higher than when EGR valve is fully closed
80 to 110 kPa
(After engine stall)

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

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


B
Go to step 4
A


3.CHECK WHETHER DTC OUTPUT RECURS (DTC P0401)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Clear the DTC.

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

  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. Switch the ECM from normal mode to check mode.

  1. Drive the vehicle at 60 km/h (37 mph) with the shift lever in B.

    CAUTION:
    1. Strictly observe speed limits and traffic laws when performing the confirmation drive pattern.

  1. Perform fuel-cut operation for 5 seconds or more, with the accelerator pedal fully released.

    HINT:
    1. If the deceleration was not completed, perform the confirmation driving pattern again.

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

  1. Input the DTCs to be confirmed.

  1. Check the DTC judgment result.

Result 
Result
Proceed to
No output
A
P0401
B

Intelligent Tester 
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. You should 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's memory limit

HINT:
  1. If the DTC judgment result is INCOMPLETE or UNKNOWN, drive the vehicle again at 60 km/h (37 mph) with the shift lever in B, perform fuel-cut operation for 5 seconds or more with the accelerator pedal fully released, and check the DTC judgment result.



B
GO TO DTC CHART (Click here)
A


4.READ OUTPUT DTC (DTC P0136, P0137 OR P0138)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read DTCs.
    Result 
    Result
    		Proceed to
    P0138
    		A
    P0137
    		B
    P0136
    		C



B
Go to step 16

C
Go to step 9
A


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

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / O2S B1S2.

  1. Allow the engine to idle.

  1. Read the heated oxygen sensor output voltage while idling.
    Result 
    Result
    		Proceed to
    More than 1.2 V
    		A
    Less than 1.0 V
    		B



B
Go to step 8
A


6.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)


    A152957E41

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

  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
    B8-63 (HT1B) - B8-80 (OX1B)
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the ECM connector.



NG
Go to step 7
OK

REPLACE ECM (Click here)  

7.INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)


    A200916E01

  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
    1 (HT1B) - 2 (+B)
    		20°C (68°F)
    		11 to 16 Ω
    2 (+B) - 3 (OX1B)
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Component without harness connected:
    (Heated Oxygen Sensor)

  1. Reconnect the heated oxygen sensor connector.



NG
REPLACE HEATED OXYGEN SENSOR (Click here)
OK

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

8.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 operation. When the sensor is normal, the sensor current will indicate below 3 mA in this test.

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Clear DTCs.



  1. Drive the vehicle by the drive 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 3 seconds or more. Repeat this process at least 3 times.


      A152792E02

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Current B1S1.

  1. Read the value of the air fuel ratio sensor current while the fuel-cut operation is performing.

    Standard current:
    Less than 3.0 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.

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


B
Go to step 12
A

REPLACE AIR FUEL RATIO SENSOR (Click here)  

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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Start the engine.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / O2S B1S2.

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

  1. Read the output voltage of the heated oxygen sensor when the engine rpm is suddenly increased.

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

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



NG
Go to step 16
OK


10.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


11.CHECK WHETHER DTC OUTPUT RECURS (DTC P0136)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.
    Result 
    Result
    		Proceed to
    P0136
    		A
    No output
    		B



B
CHECK FOR INTERMITTENT PROBLEMS (Click here)
A


12.REPLACE HEATED OXYGEN SENSOR

  1. Replace the heated oxygen sensor (Click here).


NEXT


13.PERFORM CONFIRMATION DRIVING PATTERN

NEXT


14.CHECK WHETHER DTC OUTPUT RECURS (DTC P0136)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC / Pending.
    Result 
    Result
    		Proceed to
    P0136
    		A
    No output
    		B



B
END
A


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

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine.

  1. Turn the tester on.

  1. Warm up the engine.

  1. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume.



  1. Change the fuel injection volume using the tester, and monitor the voltage output of the air fuel ratio sensor and heated oxygen sensor displayed on the tester.

    HINT:
    1. Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in 1% 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 intelligent tester.


    Result 
    Tester Display (Sensor)
    		Voltage Variation
    		Proceed to
    AFS Voltage B1S1 (A/F)
    		Alternates between more and less than 3.3 V
    		OK
    AFS Voltage B1S1 (A/F)
    		Remains at more than 3.3 V
    		NG
    AFS Voltage B1S1 (A/F)
    		Remains at less than 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 less or more than 3.3 V despite the heated oxygen sensor indicating a normal reaction, the air fuel ratio sensor is malfunctioning.


    A121606E04



NG
REPLACE AIR FUEL RATIO SENSOR (Click here)
OK

REPAIR OR REPLACE CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (FUEL INJECTOR, FUEL PRESSURE, EXHAUST GAS LEAK, ETC.) (Click here)  

16.CHECK FOR EXHAUST GAS LEAK

OK:
No gas leak.



NG
REPAIR OR REPLACE EXHAUST GAS LEAK POINT
OK


17.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)


    A200916E01

  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
    1 (HT1B) - 2 (+B)
    		20°C (68°F)
    		11 to 16 Ω
    1 (HT1B) - 4 (E2)
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Component without harness connected:
    (Heated Oxygen Sensor)

  1. Reconnect the heated oxygen sensor connector.



NG
REPLACE HEATED OXYGEN SENSOR (Click here)
OK


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


    A200841E02

  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 (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    B19-1 (HT1B)*3 - B8-63 (HT1B)
    		Always
    		Below 1 Ω
    B19-3 (OX1B)*3 - B8-80 (OX1B)
    		Always
    		Below 1 Ω
    B19-4 (E2)*3 - B8-79 (O1B-)
    		Always
    		Below 1 Ω
    B20-1 (HT1B)*4 - B8-63 (HT1B)
    		Always
    		Below 1 Ω
    B20-3 (OX1B)*4 - B8-80 (OX1B)
    		Always
    		Below 1 Ω
    B20-4 (E2)*4 - B8-79 (O1B-)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    B19-1 (HT1B)*3 or B8-63 (HT1B) - Body ground
    		Always
    		10 kΩ or higher
    B19-3 (OX1B)*3 or B8-80 (OX1B) - Body ground
    		Always
    		10 kΩ or higher
    B19-4 (E2)*3 or B8-79 (O1B-) - Body ground
    		Always
    		10 kΩ or higher
    B20-1 (HT1B)*4 or B8-63 (HT1B) - Body ground
    		Always
    		10 kΩ or higher
    B20-3 (OX1B)*4 or B8-80 (OX1B) - Body ground
    		Always
    		10 kΩ or higher
    B20-4 (E2)*4 or B8-79 (O1B-) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Heated Oxygen Sensor)
    *2
    		Front view of wire harness connector:
    (to ECM)
    *3
    		for CVT
    *4
    		for Manual Transaxle

  1. Reconnect the heated oxygen sensor connector.



  1. Reconnect the ECM connector.


    A201297E01



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE HEATED OXYGEN SENSOR (Click here)