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

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC (Three-Way Catalytic Converter) is used. For the most efficient use of the TWC, 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 TWC, 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-TWC 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-TWC 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 TWC 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.

Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan).
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, heated oxygen sensor voltage does not increase to more than 0.69 V for certain period of time (2 trip detection logic) Low impedance: Sensor impedance less than 5 Ω for more than 30 seconds when ECM presumes sensor is warmed up and operating normally (2 trip detection logic)	Heated oxygen sensor (sensor 2) Air fuel ratio sensor (sensor 1) Gas leak from exhaust system Fuel pressure Fuel injector PCV valve and hose Intake system
P0137	Low voltage (open): During active air fuel ratio control, following conditions (a) and (b) met for 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 High impedance: Sensor impedance 15 kΩ or more for more than 90 seconds when ECM presumes sensor to be warmed up and operating normally (2 trip detection logic)	Open or short in heated oxygen sensor (sensor 2) circuit Heated oxygen sensor (sensor 2) Heated oxygen sensor heater (sensor 2) Air fuel ratio sensor (sensor 1) Gas leak from exhaust system
P0138	Extremely high voltage (short): Heated oxygen sensor voltage output exceeds 1.2 V for more than 10 seconds (2 trip detection logic)	Short in heated oxygen sensor (sensor 2) circuit Heated oxygen sensor (sensor 2) ECM
P0139	Heated oxygen sensor (sensor 2) voltage does not drop to below 0.2 V immediately after fuel cut starts (2 trip detection logic) Heated oxygen sensor (sensor 2) voltage does not drop from 0.35 V to 0.2 V immediately after fuel cut status (2 trip detection logic)	Short in heated oxygen sensor (sensor 2) circuit Heated oxygen sensor (sensor 2) Gas leak from exhaust system ECM

for Mexico Models
DTC No.	DTC Detection Conditions	Trouble Areas
P0136	Not applicable	None
P0137	Low voltage (open): During active air fuel ratio control, following conditions (a) and (b) met for 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	Open or short in heated oxygen sensor (sensor 2) circuit Heated oxygen sensor (sensor 2) Heated oxygen sensor heater (sensor 2) Air fuel ratio sensor (sensor 1) Gas leak from exhaust system
P0138	Not applicable	None
P0139	Not applicable	None

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 (TWC) and heated oxygen sensor malfunctions (refer to the diagram below).
Active air fuel ratio control is performed for approximately 15 to 20 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 increase to more than 0.69 V during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormal and stores DTC P0136.

Open in Heated Oxygen Sensor Circuit (DTC P0137)

During active air fuel ratio control, the ECM calculates the Oxygen Storage Capacity (OSC)* of the Three-Way Catalytic Converter (TWC) by forcibly regulating the air fuel ratio to become rich or lean.
If the heated oxygen sensor has an open, or the voltage output of the sensor noticeably decreases, the OSC 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 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and stores DTC P0137.

HINT:

*: The TWC has the capability to store oxygen. The OSC and the emission purification capacity of the TWC are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated OSC value (YARIS_NCP93 RM000000WC00BXX_01.html).

High or Low Impedance of Heated Oxygen Sensor (DTCs P0136 or P0137)

During normal air fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variation of the heated oxygen sensor signal while the engine is running, the impedance* of the sensor is measured by the ECM. The ECM determines that there is a malfunction in the sensor when the measured impedance deviates from the standard range.
*: The effective resistance in an alternating current electrical circuit.

HINT:

The impedance cannot be measured using an ohmmeter.
DTCs P0136 indicate the deterioration of the heated oxygen sensor. The ECM stores the DTCs by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycles).
DTCs P0137 indicate an open or short circuit in the heated oxygen sensor (2 driving cycles). The ECM stores the DTCs when the impedance of the sensor exceeds the threshold 15 kΩ.

Extremely High Output Voltage of Heated Oxygen Sensor (DTC P0138)

The ECM continuously monitors the heated oxygen sensor output voltage while the engine is running.
DTC P0138 is stored if the heated oxygen sensor voltage output is more than 1.2 V for 10 seconds or more.

Abnormal Voltage Output of Heated Oxygen Sensor During Fuel-cut (DTC P0139)

The sensor output voltage drops to below 0.2 V (extremely lean status) immediately when the vehicle decelerates and fuel cut is operating. If the voltage does not drop to below 0.2 V for 7 seconds or more, or voltage does not drop from 0.35 V to 0.2 V for 1 second, the ECM determines that the sensor response has deteriorated, illuminates the MIL and stores a DTC.

MONITOR STRATEGY

Related DTCs	P0136: Heated oxygen sensor output voltage (Output voltage) P0136: Heated oxygen sensor impedance (Low) P0137: Heated oxygen sensor output voltage (Low voltage) P0137: Heated oxygen sensor impedance (High) P0138: Heated oxygen sensor output voltage (Extremely high) P0139: Heated oxygen sensor output voltage during fuel cut
Required Sensors/Components (Main)	Heated oxygen sensor (sensor 2)
Required Sensors/Components (Related)	Crankshaft position sensor Engine coolant temperature sensor Mass air flow meter Throttle position sensor Air fuel ratio sensor
Frequency of Operation	Once per driving cycle: Active air fuel ratio control detection, heated oxygen sensor abnormal voltage during fuel cut. Continuous: Other
Duration	20 seconds: Heated oxygen sensor output (Output voltage, Low voltage) 30 seconds: Heated oxygen sensor impedance (Low) 90 seconds: Heated oxygen sensor impedance (High) 10 seconds: Heated oxygen sensor voltage (Extremely high) 7 seconds: Heated oxygen sensor voltage during fuel cut
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

All:

Monitor runs whenever following DTCs not present

P0016 (VVT System - Misalignment)
P0031, P0032 (Air Fuel Ratio Sensor Heater)
P0037, P0038 (Heated Oxygen Sensor Heater)
P0102, P0103 (Mass Air Flow Meter)
P0112, P0113 (Intake Air Temperature Sensor)
P0115, P0117, P0118 (Engine Coolant Temperature Sensor)
P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor)
P0125 (Insufficient Coolant Temperature for Closed Loop Fuel Control)
P0128 (Thermostat)
P0171, P0172 (Fuel System)
P0301 - P0304 (Misfire)
P0335 (Crankshaft Position Sensor)
P0340 (Camshaft Position Sensor)
P0451 - P0453 (EVAP System)
P0500 (Vehicle Speed Sensor)
P2195, P2196, P2237, P2238, P2239, P2252, P2253, P014C, P014D, P015A, P015B (Air Fuel Ratio Sensor)
P219A (Air Fuel Ratio Imbalance)

Heated Oxygen Sensor Output Voltage (Output Voltage and Low Output Voltage):
Active air fuel ratio control	Executing
Active air fuel ratio control begins when all of following conditions met:	-
Battery voltage	11 V or more
Intake air temperature	-10°C (14°F) or more
Engine coolant temperature	75°C (167°F) or more
Idling	OFF
Engine speed	Less than 4000 rpm
Air fuel ratio sensor status	Activated
Fuel system status	Closed loop
Fuel cut	OFF
Engine load	10 to 80%
Shift position	3rd or more

Heated Oxygen Sensor Impedance (Low):
Battery voltage	11 V or more
Estimated sensor temperature	Less than 700°C (1292°F)
ECM monitor	Completed
DTC P0607	Not set

Heated Oxygen Sensor Impedance (High):
Battery voltage	11 V or more
Estimated sensor temperature	450 to 750°C (842 to 1382°F) or higher
DTC P0607	Not set

Heated Oxygen Sensor Output Voltage (Extremely High):
Battery voltage	11 V or more
Time after engine start	2 seconds or more

Heated Oxygen Sensor Voltage During Fuel Cut:
Engine coolant temperature	75°C (167°F) or more
Catalyst temperature	400°C (752°F) or more
Fuel cut	ON

TYPICAL MALFUNCTION THRESHOLDS

Heated Oxygen Sensor Output Voltage (Output Voltage):
All of following conditions (a), (b) and (c) met	-
(a) Commanded air fuel ratio	14.3 or less
(b) Rear heated oxygen sensor voltage	0.21 to 0.69 V
(c) OSC (Oxygen Storage Capacity of Catalyst)	1.8 g or more

Heated Oxygen Sensor Output Voltage (Low Output Voltage):
All of following conditions (a), (b) and (c) met	-
(a) Commanded air fuel ratio	14.3 or less
(b) Rear heated oxygen sensor voltage	Less than 0.21 V
(c) OSC (Oxygen Storage Capacity of Catalyst)	1.8 g or more

Heated Oxygen Sensor Impedance (Low):
Duration of following condition	30 seconds or more
Heated oxygen sensor impedance	Less than 5 Ω

Heated Oxygen Sensor Impedance (High):
Duration of following condition	90 seconds or more
Heated oxygen sensor impedance	15 kΩ or more

Heated Oxygen Sensor Output Voltage (Extremely High):
Duration of following condition	10 seconds or more
Heated oxygen sensor voltage	1.2 V or higher

Heated Oxygen Sensor Voltage During Fuel-cut:
Duration until rear heated oxygen sensor voltage drops to 0.2 V after fuel cut	7 seconds or more
Duration until rear heated oxygen sensor voltage drops from 0.35 V to 0.2 V during fuel cut	1 second or more

COMPONENT OPERATING RANGE

Duration of following condition	30 seconds or more
Heated oxygen sensor voltage	Varies between 0.1 V and 0.9 V

MONITOR RESULT

Refer to detailed information in Checking Monitor Status (YARIS_NCP93 RM000000PDR0B4X.html).

P0137: O2 Sensor / MAX VOL B1S2
Monitor ID	Test ID	Scaling	Unit	Description
$02	$08	Multiply by 0.001	V	Maximum sensor voltage

P0139: O2 Sensor / RL F/C B1S2
Monitor ID	Test ID	Scaling	Unit	Description
$02	$8B	Multiply by 0.001	Seconds	0.35 - 0.2 V sensor switch time

P0139: O2 Sensor / F/C TIME B1S2
Monitor ID	Test ID	Scaling	Unit	Description
$02	$8D	Multiply by 0.001	Seconds	Duration that sensor voltage drops to 0.2 V during fuel-cut

P0136: O2 Sensor / MAX OSC B1S2
Monitor ID	Test ID	Scaling	Unit	Description
$02	$8F	Multiply by 0.0003	g	Maximum oxygen storage capacity

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 driving pattern will activate the heated oxygen sensor monitor (The catalyst monitor is performed simultaneously). This is very useful for verifying the completion of a repair.

P0136, P0137 and P0138

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on [A].
Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [B].
With the transmission in 4th gear or higher, drive the vehicle at 60 to 120 km/h (38 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 / Trouble Codes [D].
Read pending DTCs.
HINT:
1. If a pending DTC is output, the system is malfunctioning.
2. 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, P0137 or P0138.

Check the DTC judgment result.

Techstream 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 memory limit

HINT:

If the judgment result shows INCOMPLETE or N/A, perform steps [C] through [D].

If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
HINT:
1. If a permanent DTC is output, the system is malfunctioning.
2. If no permanent DTC is output, the system is normal.

P0139

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on [A].
Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [B].
Drive the vehicle at 60 km/h (38 mph), and then decelerate the vehicle by releasing the accelerator pedal for 8 seconds or more to perform the fuel-cut [C].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [D].
Read DTCs.
HINT:
1. If a pending DTC or current DTC is output, the system is malfunctioning.
2. If a pending DTC or current DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0139.

Check the DTC judgment result.

Techstream 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 memory limit

HINT:

If the judgment result shows INCOMPLETE or N/A, shift the transmission to 2nd gear (2nd range), and then perform steps [C] and [D] again.

If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
HINT:
1. If a permanent DTC is output, the system is malfunctioning.
2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0031 (YARIS_NCP93 RM000000WC10MFX_07.html).

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 Techstream.

Connect the Techstream to the DLC3.
Start the engine.
Turn the Techstream 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.
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 Techstream.

HINT:

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.

Techstream Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 (Air fuel ratio)	+12%	Rich	Below 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	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 (Bank 1 Sensor 1) Output Voltage	Heated Oxygen Sensor (Bank 1 Sensor 2) 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 injector assembly Fuel pressure Gas leak from exhaust system (Air fuel ratio extremely rich or lean)

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.
To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / AFS Voltage B1S1 and O2S B1S2; and then press the graph button on the Data List view.

NOTICE:

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

HINT:

Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Read freeze frame data using the Techstream. 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 OUTPUT DTC (DTC P0136, P0137, P0138 AND P0139)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read DTCs.
Result
Result
Proceed to
P0138 is output
A
P0137 is output
B
P0136 is output
C
P0139 is output
D
P0136, P0137 or P0138 and other DTCs are output
E
HINT:
If any DTCs other than P0136, P0137, P0138 or P0139 are output, troubleshoot those DTCs first.

Result
Result	Proceed to
P0138 is output	A
P0137 is output	B
P0136 is output	C
P0139 is output	D
P0136, P0137 or P0138 and other DTCs are output	E

Go to step 6

Go to step 4

Go to step 15

GO TO DTC CHART (YARIS_NCP93 RM000000PDF0EWX.html)

A

2.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
Text in Illustration
*a
Component without harness connected
(Heated Oxygen Sensor)

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

REPLACE HEATED OXYGEN SENSOR (YARIS_NCP93 RM000003VIP00IX.html)

OK

3.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)

Turn the ignition switch to off and wait for 5 minutes or more.

Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection
Condition
Specified Condition
C51-22 (HT1B) - C51-103 (OX1B)
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

4.PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Warm up the engine.

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

Change the fuel injection volume using the Techstream, and monitor the voltage output of heated oxygen sensor displayed on the Techstream.
HINT:
1. Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in fine gradations within the 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 voltage:
Fluctuates between 0.4 V or less and 0.55 V or more.

Go to step 6

OK

5.PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Warm up the engine.

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

Change the fuel injection volume using the Techstream, and monitor the voltage output of air fuel ratio and heated oxygen sensors displayed on the Techstream.
HINT:
1. Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in fine gradations within the 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 Techstream.
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
Techstream Display (Sensor)
Voltage Variation
Proceed to
AFS Voltage B1S1 (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
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.

Go to step 12

CHECK ENGINE TO DETERMINE CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (FUEL INJECTOR, FUEL SYSTEM, INTAKE SYSTEM, ETC.) (YARIS_NCP93 RM000000WC30JKX_07.html)

6.CHECK FOR EXHAUST GAS LEAK

Inspect for exhaust gas leaks from the exhaust manifold sub-assembly and exhaust pipes.
OK:
No gas leakage.
HINT:
Perform "Inspection After Repair" after repairing or replacing the exhaust system (YARIS_NCP93 RM000004NJD006X.html).

REPAIR OR REPLACE EXHAUST GAS LEAK POINT (YARIS_NCP93 RM000002WV200NX.html)

OK

7.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Inspect the heated oxygen sensor (YARIS_NCP93 RM000003VIN00GX.html).

REPLACE HEATED OXYGEN SENSOR (YARIS_NCP93 RM000003VIP00IX.html)

OK

8.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:

Tester Connection	Condition	Specified Condition
D145-1 (HT1B) - C51-22 (HT1B)	Always	Below 1 Ω
D145-3 (OX1B) - C51-103 (OX1B)
D145-4 (E2) - C51-135 (EX1B)
D145-1 (HT1B) or C51-22 (HT1B) - Body ground	Always	10 kΩ or higher
D145-3 (OX1B) or C51-103 (OX1B) - Body ground

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

9.REPLACE HEATED OXYGEN SENSOR

Replace the heated oxygen sensor (YARIS_NCP93 RM000003VIP00IX.html).

NEXT

10.PERFORM CONFIRMATION DRIVING PATTERN

Perform the Confirmation Driving Pattern (P0136, P0137 and P0138).

NEXT

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

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Input DTCs: P0136, P0137 and P0138.

Check that the DTC monitor is NORMAL. If the DTC monitor is INCOMPLETE, perform the drive 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
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (YARIS_NCP93 RM000004NJD006X.html).

END

REPLACE AIR FUEL RATIO SENSOR (YARIS_NCP93 RM000003VIL00HX.html)

12.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor (YARIS_NCP93 RM000003VIL00HX.html).
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (YARIS_NCP93 RM000004NJD006X.html).

NEXT

13.PERFORM CONFIRMATION DRIVING PATTERN

Perform the Confirmation Driving Pattern (P0136, P0137 and P0138).

NEXT

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

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Input DTCs: P0136, P0137 and P0138.

Check that the DTC monitor is NORMAL. If the DTC monitor is INCOMPLETE, perform the drive pattern again but increase the vehicle speed.
Result
Result
Proceed to
NORMAL
(DTC is not output)
A
ABNORMAL
(DTC P0136, P0137 or P0138 is output)
B

REPLACE HEATED OXYGEN SENSOR (YARIS_NCP93 RM000003VIP00IX.html)

END

15.CHECK FOR EXHAUST GAS LEAK

Inspect for exhaust gas leaks from the exhaust manifold sub-assembly and exhaust pipes.
OK:
No gas leakage.
HINT:
Perform "Inspection After Repair" after repairing or replacing the exhaust system (YARIS_NCP93 RM000004NJD006X.html).

REPAIR OR REPLACE EXHAUST GAS LEAK POINT (YARIS_NCP93 RM000002WV200NX.html)

OK

16.INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)

Turn the ignition switch off and wait for 5 minutes or more.

Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection
Condition
Specified Condition
C51-22 (HT1B) - C51-103 (OX1B)
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

17.PERFORM CONFIRMATION DRIVING PATTERN

Perform the Confirmation Driving Pattern (P0139).

NEXT

18.READ DTC OUTPUT (DTC P0139 IS OUTPUT AGAIN)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Input DTCs: P0139.

Check that the DTC monitor is NORMAL. If the DTC monitor is INCOMPLETE, perform the drive pattern again but increase the vehicle speed.
Result
Result
Proceed to
ABNORMAL
(DTC P0139 is output)
A
NORMAL
(DTC is not output)
B

CHECK FOR INTERMITTENT PROBLEMS (YARIS_NCP93 RM000000PDQ0Q2X.html)

REPLACE HEATED OXYGEN SENSOR (YARIS_NCP93 RM000003VIP00IX.html)

Techstream Display (Sensor)	Voltage Variation	Proceed to
AFS Voltage B1S1 (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

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

Result	Proceed to
ABNORMAL (DTC P0139 is output)	A
NORMAL (DTC is not output)	B