Electronic Spark Control Module: Description and Operation

Knock Control Unit (KCU, Part 2):

PURPOSE
The Knock Control Unit (KCU) acts as a signal filter allowing only knocking signals considered above normal engine vibrations to reach the Electronic Control Assembly (ECA).

OPERATION
When abnormal vibration (knocking) occurs, voltage is generated by the knock sensor and a signal is sent through the KCU to the ECA. The ECA then retards ignition timing and reduces turbo boost pressure until knock is eliminated.