Inspection Procedure: Notes

WARNING: This page is about a different variant/trim than selected.

HINT:

Hand-held tester only:

Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL function can help to determine whether the Heated Oxygen (HO2) sensors and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the A/F CONTROL operation using a hand-held tester.

Connect a hand-held tester to the DLC3.
Start the engine and turn the tester ON.
Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
Monitor the voltage output of the HO2 sensors (O2S B1S1 and OS2 B1S2) displayed on the tester.

HINT:

The A/F CONTROL 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.

Standard:

HO2S SENSOR INJECTION VOLUME AND VOLTAGES

Tester Display (Sensor)	Injection Volumes	Status	Voltages
O2SB1S1 (Front HO2 Sensor)	+25 %	Rich	More than 0.5
O2SB1S1 (Front HO2 Sensor)	-12.5%	Lean	Less than 0.4
O2SB1S2 (Rear HO2 Sensor)	+25 %	Rich	More than 0.5
O2SB1S2 (Rear HO2 Sensor)	-12.5%	Lean	Less than 0.4

NOTE: The front HO2 sensor has an output delay of a few seconds and the rear HO2 sensor has a maximum output delay of approximately 20 seconds.

Fig 1: HO2S Sensor Output Voltage Chart

Following A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the front and rear HO2 sensors.
To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST/ A/F CONTROL /USER DATA / AFS B1S2 and OS2 B1B2, and press the YES button and then the ENTER button followed by the F4 button.

NOTE: If the vehicle is short of fuel, the air-fuel ratio becomes lean and HO2 sensor DTCs are recorded, and the ECM illuminates the MIL.

HINT:

If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record 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.
A high HO2 sensor (sensor 1) voltage (0.5 V or more) could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
A low HO2 sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.