Conditioning For Sensor Testing
HINT:
Perform the operation with the engine speeds and time durations described below prior to checking the waveformsFig 2 of the air fuel ratio sensor and heated oxygen sensor. This is to activate the sensors sufficiently to obtain the appropriate inspection results.
- (a) Connect the Techstream to the DLC3 [A].
- (b) Turn the power switch on (IG) and turn the Techstream on [B].
- (c) Put the engine in inspection mode. Refer toINSPECTION MODE PROCEDURE [C].
- (d) Start the engine and warm it up with all the accessories switched off until the engine coolant temperature stabilizes [D].
- (e) Run the engine at an engine speed of 2500 rpm for at least 3 minutes [E].
- (f) While running the engine at 2500 rpm for 2 seconds and 1500 rpm for 2 seconds, check the waveforms Fig 2of the air fuel ratio and heated oxygen sensors using the Techstream [F].
HINT:
- If either voltage output of the air fuel ratio or heated oxygen sensor does not fluctuate, or there is noise in the waveformFig 2 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, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.
- If the three-way catalytic converter has deteriorated, the heated oxygen sensor (located behind the three-way catalytic converter) voltage output fluctuates up and down frequently, even under normal driving conditions (active air fuel ratio control is not performed).