VUE AWD V6-3.5L (2007)
point as the expected knocking frequency of the engine. When engine detonation is detected, the sensor signals the PCM to reduce the spark advance
until detonation is no longer detected.
In response to the KS signal the PCM retards the spark advance in order to reduce the detonation. The amount of timing retard that the PCM applies is
based on the engine speed and the length of time that the engine detonation is detected. Once the spark timing is retarded, the KS circuitry in the PCM
performs calculations in order to determine how much spark advance should be re-introduced. Normally the ignition timing advance is increased until
zero retard, or normal ignition timing, is re-established. If detonation occurs again, the whole cycle will repeat. The alteration of the ignition timing by
the KS often occurs continuously while the engine is running, even though no detonation is heard by the vehicle's operator.
Results of Faulty Knock Sensor Operation
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
A KS that fails to detect detonation can cause 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
