Results of Faulty Knock Sensor Operation

Loss of the KS signal or loss of ground at the KS module causes the KS signal to the PCM to remain high. A constantly high input to the PCM from the KS causes the PCM to control the ignition timing as if no detonation were occurring. Failure of the PCM to retard the ignition timing when necessary could cause any of the following concerns:
^ An excessive engine detonation
^ Engine damage during heavy engine loads
^ Higher exhaust emissions

A KS that falsely indicates detonation can cause the PCM to retard the ignition timing unnecessarily. Reduced spark advance can cause any of the following conditions:
^ Poor fuel economy
^ Sluggish engine performance
^ Higher exhaust emissions