Knock Sensor: Testing and Inspection

The engine knock sensor is affected by a number of factors. A few of these are:
- Ignition Timing
- Cylinder Pressure
- Fuel Octane etc

The knock sensor generates an AC voltage whose amplitude increases with the increase of engine knock.

The knock sensor can be tested with a digital voltmeter.
- RMS voltage starts at about 20mVac -- at about 700 rpm
- and increases to approximately 600 mVac -- at 5,000 rpm.

If the output falls outside of this range a DTC will be set.