The loss of the knock sensor signal or the loss of a ground at the KS module would cause the signal to the ECM to remain high. This condition would cause the ECM to control the spark timing as if there was no spark knock. A no retard would occur, and the spark knocking could become severe under heavy engine load conditions.

The spark retard without the knock sensor connected could indicate a noise signal on the wire to the ECM or a malfunctioning KS module.

The loss of the KS signal to the ECM would cause the ECM to constantly retard the spark timing. This could result in a sluggish performance and cause a DTC 43 to set.

When no DTC 43 is present but the KS system is a possible cause of the excessive spark knock, refer to Knock Sensor (KS) System Check table for diagnosis.

DTC 43 indicates that the ECM is receiving less than 6 volts for a 4 second period with the engine running. If DTC is present, refer to DTC 43 Knock Sensor Circuit Error .