Conditioning For Sensor Testing

Perform the operation with the engine speeds and time durations described below prior to checking the waveforms of the A/F and HO2 sensors. This is performed in order to heat the sensors sufficiently to obtain the appropriate inspection results.

Fig 1: Engine Speed Driving Pattern

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Connect Techstream to the DLC3 (Procedure "A").
Start the engine and warm it up with all the accessories switched off, until the engine coolant temperature stabilizes (Procedure "B").
Run the engine at an engine speed of between 2,500 rpm and 3,000 rpm for at least 3 minutes (Procedure "C").

While running the engine at 3,000 rpm for 2 seconds and 2,000 rpm for 2 seconds, check the waveforms of the A/F and HO2 sensors using the tester or scan tool (Procedure "D").

NOTE: The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.

A/F SENSOR OUTPUT VOLTAGE REFERENCE

Case	A/F Sensor (Sensor 1) Output Voltage		HO2 Sensor (Sensor 2) Output Voltage		Main Suspected Trouble Area
1	Injection Volume +25 % -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume +25 % -12 5 %	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
1	Output Voltage More than 3 35 V Less than 3 0V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage More than 0 55 V Less than 0 4V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
2	Injection Volume +25 % -12 5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume +25 % -12 5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	A/F sensor A/F sensor heater A/F sensor circuit
2	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage More than 0.55 V Less than 0 4V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	A/F sensor A/F sensor heater A/F sensor circuit
3	Injection Volume +25 % -12.5 %	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume +25 % -12.5 %	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	HO2 sensor HO2 sensor heater HO2 sensor circuit
3	Output Voltage More than 3 35 V Less than 3.0 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	HO2 sensor HO2 sensor heater HO2 sensor circuit
4	Injection Volume +25 % -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume +25 % -12.5 %	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Fuel pressure Gas leakage from exhaust system (Air-fuel ratio extremely lean or rich)
4	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the output voltages of both the A/F and HO2 sensors.
To display the graph, enter the following menus on the tester: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 or AFS B2 S1 and O2S B1 S2 or O2S B2 S2 then press the graph button on the Data List view.