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 or Techstream to the DLC3.
- Turn the power switch ON (READY).
- Warm it up with all the accessories switched OFF, until the engine coolant temperature stabilizes.
- Run the engine at an engine speed of between 2000 rpm and 2500 rpm for at least 3 minutes.
- While running the engine at 2500 rpm and 1500 rpm for 2 second intervals, check the waveforms of the A/F and HO2 sensors using the tester.
HINT:
- If the voltage output of the Air-Fuel Ratio (A/F) or Heated Oxygen (HO2) sensor does not fluctuate, or either of the sensors makes a noise, 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 menus:
- Intelligent tester - Select. DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL
- Techstream - Select: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for N F sensor.
- 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)