Chrysler Cirrus/Stratus/Sebring/Avenger/Breeze 1995-1998

Knock Sensor



All the vehicles with 4-cylinder engines are equipped with a knock sensor, which is threaded into the side of the cylinder block, in front of the starter. When the knock sensor detects a knock in one of the cylinders, it sends an input signal to the PCM. In response, the PCM retards ignition timing for all cylinders by a scheduled amount.

Knock sensors contain a piezoelectric material which sends an input voltage (signal) to the PCM. As the intensity of the engine knock vibration increases, the knock sensor output voltage also increases.


See Figures 1 and 2

Visually check the connector, making sure it is attached properly and that all of the terminals are straight, tight and free of corrosion.

A number of factors affect the engine knock sensor. A few of these are: ignition timing, cylinder pressure, fuel octane, etc. The knock sensor produces an AC voltage whose amplitude increases with the amount of engine knock. The knock sensor can be tested with a digital voltmeter. The RMS voltage is produced at about 20mVac (at about 700 rpm) and increases to about 600mVac (5000 rpm). If the output falls outside of this range, a Diagnostic Trouble Code (DTC) will set.

Click image to see an enlarged view

Fig. Fig. 1: Knock sensor terminal for Sebring coupe and Avenger models

Click image to see an enlarged view

Fig. Fig. 2: Knock sensor terminal for Cirrus, Stratus, Sebring convertible and Breeze models


See Figure 3

  1. Disconnect the negative battery cable.
  3. Unplug the electrical connector from the knock sensor, which is located on the engine block, in front of the starter.

Click image to see an enlarged view

Fig. Fig. 3: The knock sensor is located on the side of the engine block, in front of the starter motor

  1. Use a crow's foot wrench to remove the knock sensor from the vehicle.

To install:
  1. Install the sensor in the vehicle and tighten to 7 ft. lbs. (10 Nm). Make sure not to over or under-tighten the sensor, as is could adversely affect knock sensor performance, causing improper spark control.
  3. Attach the knock sensor electrical connector.
  5. Connect the negative battery cable.