The knock sensor is normally mounted to the rear side of the engine block. It reacts to the ping or knock caused during detonation by sending a signal to the ECU. The ECU retards the timing to eliminate the detonation.
If the knock sensor is experiencing functional problems, a slight reduction in engine power may be felt. This is because the ignition timing will be forcibly retarded.
See Figures 1 and 2
The knock sensor test requires the use of an oscilloscope.
- Position test probe of oscilloscope lead to the oscilloscope pick-up point as shown in the illustration.
- Start the engine and allow to idle. Accelerate the engine to a maximum speed of 5,000 rpm and check the waveform on the scope.
- If the test pattern obtained differentiates from the desired pattern shown in the illustration, replace the knock sensor.
REMOVAL & INSTALLATION
See Figures 3 and 4
- Disconnect the negative battery cable.
- For 2.0L non-turbo engines, remove the engine under cover.
- Detach the electrical connector at the sensor.
- For 2.0L turbo engines, remove the intake manifold stay.
- Remove the sensor from the engine block.
- Install the knock sensor in the opening in the engine block and tighten the sensor retainer.
- Attach the electrical connector to the sensor.
- Connect the negative battery cable.