2Az-Fe Engine Control System. Dtc P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)

A three way catalytic converter is used in order to convert carbon monoxide, hydrocarbons and nitrogen oxide 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 a 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 primary air fuel ratio control.

Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.2Az-Fe Engine Control System.Sfi System.
Dtc
P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)

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

WIRING DIAGRAM

Refer to DTC P2195 (RAV4_ACA30 RM000000WC40H1X_07.html).

CONFIRMATION DRIVING PATTERN

HINT:

This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" procedure of the following diagnostic troubleshooting procedure.
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.

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 / Clear.
Clear DTCs.
Start the engine and warm it up (Procedure "A").
Drive the vehicle at a speed between 90 km/h and 110 km/h (56 mph and 68 mph) for at least 10 minutes (Procedure "B").
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input DTCs: P0136, P0137 and P0138.
Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the driving pattern by accelerating the vehicle to a higher speed and using second gear to decelerate the vehicle.

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.
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 sensor and heated oxygen sensor (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 sensor)	+25%	Rich	Below 3.1 V
AFS Voltage B1S1 (Air fuel ratio sensor)	-12.5%	Lean	Higher than 3.4 V
O2S B1S2 (Heated oxygen sensor)	+25%	Rich	Higher than 0.55 V
O2S B1S2 (Heated oxygen sensor)	-12.5%	Lean	Below 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 Output Voltage	Heated Oxygen Sensor Output Voltage	Main Suspected Trouble Area
1			-
2			Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3			Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4			Fuel pressure Gas leakage from exhaust system (air fuel ratio extremely lean or rich)

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

HINT:

Read freeze frame data using the 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.READ OUTPUT DTC (DTC P0136, P0137 OR P0138)

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 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

Go to step 9

Go to step 7

GO TO DTC CHART (RAV4_ACA30 RM000000PDF0CJX.html)

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 / A/F Control System / O2S B1S2.

Allow the engine to idle.

Read the heated oxygen sensor output voltage while idling.
Result
Result
Proceed to
Higher than 1.0 V
A
Below 1.0 V
B

Go to step 5

A

3.INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)

Disconnect the heated oxygen sensor connector.

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 kΩ or higher
2 (+B) - 3 (OX1B)
Always
10 kΩ or higher
*a
Component without harness connected
(heated oxygen sensor)

*a	Component without harness connected (heated oxygen sensor)

Reconnect the heated oxygen sensor connector.

REPLACE HEATED OXYGEN SENSOR (RAV4_ACA30 RM000001ROP00QX.html)

OK

4.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
B32-47 (HT1B) - B32-64 (OX1B)
Always
10 kΩ or higher

Reconnect the ECM connector.

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

REPLACE ECM (RAV4_ACA30 RM0000017UO01HX.html)

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 / Active Test / Control the Injection Volume.

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% to +12%. The injection volume can be changed in 1% 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.

Result
Tester Display (Sensor)	Voltage Variation	Proceed to
AFS Voltage B1S1 (Air fuel ratio sensor)	Alternates between higher than and below 3.3 V	OK
AFS Voltage B1S1 (Air fuel ratio sensor)	Remains at higher than 3.3 V	NG
AFS Voltage B1S1 (Air fuel ratio sensor)	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.

Go to step 15

OK

6.CHECK AIR FUEL RATIO SENSOR

HINT:

This air fuel ratio sensor test is used to check the air fuel ratio sensor current during the fuel-cut operation. When the sensor is normal, the sensor current is below 3.6 mA in this test.

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 / Clear.

Clear DTCs.

Drive the vehicle according to the driving pattern 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 to 60 km/h (40 mph) or more and then decelerate for 5 seconds or more. Repeat this process at least 3 times.

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

Read the value of the air fuel ratio sensor current while the fuel-cut operation is being performed.
Standard current:
Below 3.6 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

Go to step 12

Go to step 15

7.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.

Start the engine.

Enter the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

Change the fuel injection volume using the tester, and monitor the voltage output of the 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 the range.
2. The heated oxygen sensor is displayed as O2S B1S2 on the intelligent tester.

Result
Tester Display (Sensor)	Voltage Variation	Proceed to
O2S B1S1 (Heated oxygen sensor)	Alternates between 0.5 V or more and less than 0.4 V	OK
	Remains at 0.5 V or more	NG
	Remains at less than 0.4 V	NG

HINT:

A normal heated oxygen sensor voltage (O2S B1S2) reacts in accordance with increases and decreases in fuel injection volumes. When the heated oxygen sensor (sensor 1) voltage remains at either 0.5 V or more or less than 0.4 V despite the heated oxygen sensor indicating a normal reaction, the heated oxygen sensor (sensor 1) is malfunctioning.

Go to step 9

OK

8.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 / Active Test / Control the Injection Volume.

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% to +12%. The injection volume can be changed in 1% 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.

Result
Tester Display (Sensor)	Voltage Variation	Proceed to
AFS Voltage B1S1 (Air fuel ratio sensor)	Alternates between higher than and below 3.3 V	OK
AFS Voltage B1S1 (Air fuel ratio sensor)	Remains at higher than 3.3 V	NG
AFS Voltage B1S1 (Air fuel ratio sensor)	Remains at below 3.3 V	NG

HINT:

Go to step 15

CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO AND REPAIR CAUSE (FUEL INJECTOR, FUEL PRESSURE, GAS LEAK FROM SYSTEM, ETC.)

9.CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leakage.
OK:
No gas leakage.

REPAIR OR REPLACE EXHAUST GAS LEAK POINT

OK

10.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Inspect the heated oxygen sensor (RAV4_ACA30 RM000001Z1X00TX_01_0001.html).

REPLACE HEATED OXYGEN SENSOR (RAV4_ACA30 RM000001ROP00QX.html)

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
B19-1 (HT1B) - B32-47 (HT1B)	Always	Below 1 Ω
B19-3 (OX1B) - B32-64 (OX1B)	Always	Below 1 Ω
B19-4 (E2) - B32-87 (EX1B)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
B19-1 (HT1B) or B32-47 (HT1B) - Body ground	Always	10 kΩ or higher
B19-3 (OX1B) or B32-64 (OX1B) - Body ground	Always	10 kΩ or higher
B19-4 (E2) or B32-87 (EX1B) - Body ground	Always	10 kΩ or higher

Reconnect the heated oxygen sensor connector.

Reconnect the ECM connector.

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

OK

12.REPLACE HEATED OXYGEN SENSOR

Replace the heated oxygen sensor (RAV4_ACA30 RM000001ROP00QX.html).

NEXT

13.PERFORM CONFIRMATION DRIVING PATTERN

HINT:

Refer to Confirmation Driving Pattern.

NEXT

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

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 DTCs: P0136, P0137 and P0138.

Check that DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the driving pattern by accelerating the vehicle to a higher speed and using second gear to decelerate the vehicle.
Result
Result
Proceed to
NORMAL
(No DTC output)
A
ABNORMAL
(DTC P0136, P0137 or P0138 output)
B

REPLACE AIR FUEL RATIO SENSOR (RAV4_ACA30 RM000001RO300UX.html)

END

15.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor (RAV4_ACA30 RM000001RO300UX.html).

NEXT

16.PERFORM CONFIRMATION DRIVING PATTERN

HINT:

Refer to Confirmation Driving Pattern.

NEXT

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

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 DTCs: P0136, P0137 and P0138.

Check that DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the driving pattern by accelerating the vehicle to a higher speed and using the second gear to decelerate the vehicle.
Result
Result
Proceed to
NORMAL
(No DTC output)
A
ABNORMAL
(DTC P0136, P0137 or P0138 output)
B

REPLACE HEATED OXYGEN SENSOR (RAV4_ACA30 RM000001ROP00QX.html)

END

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

Result	Proceed to
NORMAL (No DTC output)	A
ABNORMAL (DTC P0136, P0137 or P0138 output)	B