Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Conditioning For Sensor Testing
- Connect Techstream to the DLC3.
- Put the engine in inspection mode (see SFI SYSTEM ).
- Start the engine and warm it up with all the accessories switched OFF until the engine coolant temperature becomes stable.
- Run the engine at 2,500 rpm for approximately 3 minutes.
- Run the engine at 2,500 rpm for 2 seconds and then 1,500 rpm for 2 seconds.
- Check the waveform of the oxygen sensor (sensor 2).
HINT:
If output of the A/F sensor or the heated oxygen sensor does not fluctuate or has noise, the sensor may be malfunctioning.
If voltage output of both sensors remain at LEAN or RICH, the air-fuel ratio may be extremely LEAN or RICH. In such a case, perform the following Control the Injection Volume for A/F Sensor operation in Active Test using Techstream. If the catalyst has deteriorated, the voltage output of the heated oxygen sensor fluctuates up and down widely even under normal driving ("active air-fuel ratio control" is not performed).
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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