Caution / Notice / Hint
WARNING: This page is about a different car, the 2018 Toyota Sequoia, 2017 Toyota Sequoia, and 2016 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
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 (A/F) sensor, Heated Oxygen (HO2) 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.
- On the Techstream, 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 A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
HINT:
- Change the fuel injection volume within the range of -12.5% to +12.5%
- 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.
- If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
| Tester Display (Sensor) | Injection Volume | Status | Voltage |
|---|---|---|---|
| AFS Voltage B1S1 or AFS Voltage B2S1 (A/F) |
+12.5% | Rich | Less than 3.1 V |
| AFS Voltage B1S1 or AFS Voltage B2S1 (A/F) |
-12.5% | Lean | More than 3.4 V |
| O2S B1S2 or O2S B2S2 (HO2) |
+12.5% | Rich | More than 0.55 V |
| O2S B1S2 or O2S B2S2 (HO2) |
-12.5% | Lean | Less than 0.4 V |
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.
- Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 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 or AFS Voltage B2S1 and O2S B2S2.
HINT:
- If a malfunction cannot be found when troubleshooting DTC P0420 or P0430, a lean or rich abnormality may be the cause. Perform troubleshooting by following the inspection procedure for P0171 or P0174 (System Too Lean) and P0172 or P0175 (System Too Rich).
- Read freeze frame data using the Techstream. 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.