READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION VOLUME)
READ VALUE USING INTELLIGENT TESTER (CONTROL THE INJECTOR VOLUME)
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME)
INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
PERFORM CONFIRMATION DRIVING PATTERN
CHECK WHETHER DTC OUTPUT RECURS (DTC P0136, P0137 OR P0138 IS OUTPUT AGAIN)
PERFORM CONFIRMATION DRIVING PATTERN
CHECK WHETHER DTC OUTPUT RECURS (DTC P0136 OR P0138 IS OUTPUT AGAIN)
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) |
DESCRIPTION
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. 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.
| DTC No. | DTC Detection Condition | Trouble Area |
| P0136 |
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| P0137 |
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| P0138 |
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WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to ON and turn the tester to on.
- Clear the DTCs (CAMRY_ACV40 RM000000PDK0LEX.html).
- Turn the ignition switch off and wait for at least 30 seconds.
- Turn the ignition switch to ON and turn the tester on [A].
- Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [B].
- With the transmission in 4th gear or more, 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.
- Enter the following menus: Powertrain / Engine and ECT / DTC.
- Read the pending DTCs.
- HINT:
- If a pending DTC is output, the system malfunctioning.
- If a pending DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
- Input the DTC: P0136, P0137or P0138.
- Check the DTC judgment result [D].
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
UNKNOWN - Unable to perform DTC judgment
- Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit
- HINT:
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [C] and [D] again.
- DTC judgment completed
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 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.
- Connect the intelligent tester to the DLC3.
- Start the engine and turn the tester on.
- Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
- On the tester, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
- Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
- Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.
- HINT:
- 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%.
- 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) | +25% | Rich | Less than 3.1 V |
| AFS Voltage B1S1 (Air fuel ratio) | -12.5% | Lean | More than 3.4 V |
| O2S B1S2 (Heated oxygen) | +25% | Rich | More than 0.55 V |
| O2S B1S2 (Heated oxygen) | -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 | Air Fuel Ratio Sensor (Sensor 1) Output Voltage | Heated Oxygen Sensor (Sensor 2) Output Voltage | Main Suspected Trouble Area |
| 1 |  |  | - |
| 2 |  | |
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| 3 | | |
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| 4 | | |
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- 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 and ECT / Active Test / Control the Injection Volume for A/F Sensor / AFS Voltage B1S1 and O2S B1S2 / View.
- NOTICE:
- Inspect the fuses for circuits related to this system before performing the following inspection procedure.
- HINT:
- 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 stored.
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.
| 1.READ OUTPUT DTC |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the DTCs.
- Result:
Result Proceed to DTC P0138 is output A DTC P0137 is output B DTC P0136 is output C DTC P0136, P0137 or P0138 and other DTCs are output D
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| A | |
| 2.READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR) |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / O2S B1S2.
Allow the engine to idle.
Read the heated oxygen sensor output voltage while idling.
- Result:
Heated Oxygen Sensor Output Voltage Proceed to 1.0 V or higher A Below 1.0 V B
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| A | |
| 3.INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT) |
Disconnect the heated oxygen sensor connector.
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Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition 2 (+B) - 3 (OX1B) Always 10 kΩ or higher 2 (+B) - 4 (E2) Always 10 kΩ or higher
Text in Illustration *a Component without harness connected
(Heated Oxygen Sensor (Sensor 2))
Reconnect the heated oxygen sensor connector.
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| OK | |
| 4.CHECK HARNESS AND CONNECTOR |
Turn the ignition switch off and wait for 5 minutes.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition C24-47 (HT1B) - C24-64 (OX1B) Always 10 kΩ or higher
Reconnect the ECM connector.
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| OK | ||
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| 5.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (INJECTION VOLUME) |
Connect the intelligent tester to the DLC3.
Start the engine.
Turn the tester on.
Warm up the engine.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.
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:
- Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in fine gradations within this range.
- 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.
- 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.
- Result:
Tester Display (Sensor) Voltage Variation Proceed to AFS Voltage B1S1 (Air fuel ratio) Alternates between higher than 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.
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| 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 be below 3.6 mA in this test.
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Clear the DTCs.
Warm up the engine.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / AFS Current B1S1.
Drive the vehicle according to the drive pattern listed below.
Drive the vehicle at 60 km/h (37 mph) or more for 10 minutes or more.
Stop the vehicle.
Accelerate the vehicle to 60 km/h (37 mph) or more and decelerate for 5 seconds or more. Perform this 3 times.
Read the value of the air fuel ratio sensor current while the fuel-cut operation is being performed.
- Standard current:
- Less than 3.6 mA
- HINT:
- 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.
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| 7.READ VALUE USING INTELLIGENT TESTER (CONTROL THE INJECTOR VOLUME) |
Connect the intelligent tester to the DLC3.
Start the engine.
Turn the tester on.
Warm up the engine.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / O2S B1S2.
Change the fuel injection volume using the tester, monitoring the voltage output of the heated oxygen sensor displayed on the tester.
- HINT:
- 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 has a maximum output delay of approximately 20 seconds.
- Standard voltage:
- Fluctuates between 0.4 V or less and 0.55 V or higher.
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| OK | |
| 8.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE INJECTION VOLUME) |
Connect the intelligent tester to the DLC3.
Start the engine.
Turn the tester on.
Warm up the engine.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2.
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:
- Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in fine gradations within this range.
- 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.
- 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.
- Result:
Tester Display (Sensor) Voltage Variation Proceed to AFS Voltage B1S1 (Air fuel ratio) Alternates between higher than 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.
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| OK | ||
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| 9.CHECK FOR EXHAUST GAS LEAK |
Check for exhaust gas leakage.
- OK:
- No gas leakage.
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| OK | |
| 10.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE) |
Disconnect the heated oxygen sensor connector.
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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)
Reconnect the heated oxygen sensor connector.
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| OK | |
| 11.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM) |
Disconnect the heated oxygen sensor connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
Tester Connection Condition Specified Condition C22-1 (HT1B) - C24-47 (HT1B) Always Below 1 Ω C22-3 (OX1B) - C24-64 (OX1B) Always Below 1 Ω C22-4 (E2) - C24-87 (EX1B) Always Below 1 Ω
- Standard Resistance (Check for Short):
Tester Connection Condition Specified Condition C22-1 (HT1B) or C24-47 (HT1B) - Body ground Always 10 kΩ or higher C22-3 (OX1B) or C24-64 (OX1B) - Body ground Always 10 kΩ or higher C22-4 (E2) or C24-87 (EX1B) - Body ground Always 10 kΩ or higher
Reconnect the heated oxygen sensor connector.
Reconnect the ECM connector.
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| OK | |
| 12.REPLACE HEATED OXYGEN SENSOR |
Replace the heated oxygen sensor (CAMRY_ACV40 RM0000012OM006X.html).
| NEXT | |
| 13.PERFORM CONFIRMATION DRIVING PATTERN |
Perform Confirmation Driving Pattern.
| NEXT | |
| 14.CHECK WHETHER DTC OUTPUT RECURS (DTC P0136, P0137 OR P0138 IS OUTPUT AGAIN) |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input DTC: P0136, P0137 or P0138.
Check if the STATUS is NORMAL. If STATUS is INCOMPLETE, perform the driving pattern again but increase the vehicle speed.
- Result:
Result Proceed to ABNORMAL
(DTC P0136, P0137 or P0138 is output)A NORMAL
(DTC is not output)B
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| A | ||
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| 15.REPLACE AIR FUEL RATIO SENSOR |
Replace the air fuel ratio sensor (CAMRY_ACV40 RM0000012OI006X.html).
| NEXT | |
| 16.PERFORM CONFIRMATION DRIVING PATTERN |
Perform Confirmation Driving Pattern.
| NEXT | |
| 17.CHECK WHETHER DTC OUTPUT RECURS (DTC P0136 OR P0138 IS OUTPUT AGAIN) |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input DTC: P0136 or P0138.
Check if the STATUS is NORMAL. If STATUS is INCOMPLETE, perform the driving pattern again but increase the vehicle speed.
- Result:
Result Proceed to ABNORMAL
(DTC P0136 or P0138 is output)A NORMAL
(DTC is not output)B
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| A | ||
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