Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la
If it fails: lemon-manuals.org.ua

Or, hide this message: temporarily or permanently

Electronic Spark Control Module: Description and Operation


When vibration in the engine occurs, voltage is generated by the knock sensor and a signal is sent to the knock control unit. The knock control unit determines whether the signal from the knock sensor is pre-ignition of vibration. A signal is sent to the electronic control assembly and spark timing is retarded to the intensity of the knock. The knock control unit is mounted on the firewall next to the barometric pressure sensor.