Circuit Description

Knock sensor cannot differentiate between spark knock and other similar engine noises. When knock sensor cannot eliminate noise by retarding spark timing, DTC will set. The knock circuit is continuously monitored for these parameters.

DTC will set when PCM sends an internal test knock signal into the knock detection circuit and signal is less than or greater than expected, engine speed is at 1400-4000 RPM and condition exists twice in one ignition cycle.