Circuit Description: Notes
WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The knock sensor (KS) system monitors the KS in order to determine if detonation is present. If the KS system determines that excessive knock is present, the engine control module (ECM) retards the spark timing based on the signal from the KS system. The KS produces an AC signal when specific frequencies are detected. The ECM then retards the timing until no knock is present.
The ECM tests the functionality of the internal KS signal evaluation circuitry. The KS circuitry within the ECM is responsible for receiving, amplifying, filtering, and evaluating the AC voltage and frequency from the KS. The ECM performs 2 tests that determine if the internal circuitry within the ECM is functioning correctly.