On-Vehicle Inspection

INSPECT AIR FUEL RATIO SENSOR (for Bank 1)

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

Fig 1: Identifying Air Fuel Ratio Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard Resistance

Tester Connection	Condition	Specified Condition
1 (HA1A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
1 (HA1A) - 4 (A1A-)	Always	10 kΩ or higher

If the result is not as specified, replace the air fuel ratio sensor.

INSPECT AIR FUEL RATIO SENSOR (for Bank 2)

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

Fig 2: Identifying Air Fuel Ratio Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard Resistance

Tester Connection	Condition	Specified Condition
1 (HA2A) - 2 (+B)	20°C (68°F)	1.8 to 3.4 Ω
1 (HA2A) - 4 (A2A-)	Always	10 kΩ or higher

If the result is not as specified, replace the air fuel ratio sensor.

INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM

HINT:

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 Techstream.

Connect the Techstream to the DLC3.
Start the engine and 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 / Active Test / Control the Injection Volume for A/F sensor.
Perform the Active Test operation with the engine in an idling condition (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 B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the Techstream.

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 B1 S1 or AFS B2 S1 (A/F)	+25%	Rich	Less than 3.0 V
AFS B1 S1 or AFS B2 S1 (A/F)	-12.5%	Lean	More than 3.35 V
O2S B1 S2 or O2S B2 S2 (HO2)	+25%	Rich	More than 0.55 V
O2S B1 S2 or O2S B2 S2 (HO2)	-12.5%	Lean	Less than 0.4 V

NOTE:

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	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	-
2	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	A/F sensor A/F sensor heater A/F sensor circuit
3	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	HO2 sensor HO2 sensor heater HO2 sensor circuit
4	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002 Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002© TOYOTA, LICENSE AGREEMENT TMS1002	Injector Fuel pressure Gas leaks from exhaust system (Air-fuel ratio extremely rich or lean)

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 sensors.
To display the graph, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2.