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 logical successor to CHARM, I recommend you try it!

Link: lemon-manuals.la

Electronic Spark Control (ESC)

Wiring Diagram For ESC System:





Electronic Spark Control (ESC) is accomplished with a module that sends a voltage signal to the ECM. As the sensor detects engine knock, the voltage from the ESC module to the ECM is reduced. This signals the ECM to retard the timing, if engine speed is over approximately 900 rpm.