Detecting Condition

DETECTING CONDITION
If the ECM detects the above diagnosis conditions, it operates the fail safe function in which the corrective retard angle value is set to the maximum value.




WIRING DIAGRAM

INSPECTION USING OSCILLOSCOPE
- With the engine racing (4,000 rpm) measure between terminals KNKR, KNKL of ECM and body ground.




HINT: The correct waveform is as shown.

- Spread the time on the horizontal axis, and confirm that period of the wave is 141 per sec. (Normal mode vibration frequency of knock sensor: 7.1 KHz).




HINT: If normal mode vibration frequency is not 7.1 KHz, the sensor is malfunctioning.