Ignition Timing Operation: ESC

The 2.8L, 4.3L, 5.0L, and 5.7L engines use the Electronic Spark Control (ESC) system. This system consists of three main components: ESC module, knock sensor, and ECM. Under normal conditions (no spark knock, the ESC module sends a voltage signal of 8-10 volts to the ECM, and the ECM provides normal spark advance.

If the knock sensor detects spark knock, it signals the ESC module which then turns off the voltage signal to the ECM. The ECM retards ignition timing as needed to reduce knock. A fault in the ESC system should result in sluggish performance and set Code 43.