Conditioning For Sensor Testing
HINT:
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 in order to activate the sensors sufficiently to obtain the appropriate inspection results.
- Connect the intelligent tester 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 2500 RPM and 3000 RPM for at least 3 minutes. (Procedure "C")
- While running the engine at 3000 RPM and 2000 RPM alternating at 2 second intervals, check the waveforms of the A/F and HO2 sensors using the tester. (Procedure "D")
HINT:
- If either voltage output of the Air-Fuel Ratio (A/F) or Heated Oxygen (HO2) sensor does not fluctuate, or there is a noise in the waveform of either sensor, the sensor may be malfunctioning.
- If the voltage outputs of both the sensors remain lean or rich, the air-fuel ratio may be extremely lean or rich. In such cases, perform the following A/F CONTROL using the intelligent tester.
- If the Three-Way Catalytic Converter (TWC) has deteriorated, the HO2 sensor (located behind the TWC) voltage output fluctuates up and down frequently, even under normal driving conditions (active air-fuel ratio control is not performed).