Grand Prix V6-204 3.4L DOHC (1992)
Electronic Spark Timing: Description and Operation
The Electronic Spark Control (ESC) has two major components:
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ESC Module (part of the MEM-CAL).
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ESC knock sensor.
The ESC knock sensor detects abnormal vibration (detonation) in the engine. When a knock is detected, the ESC module tells the PCM to modify the
output (EST signal) to the ignition module, retarding the spark timing. When the knocking stops, the PCM advances timing in small increments back to
its preset value. This allows the PCM to maintain optimum ignition timing advance for better fuel economy and performance under all operating
conditions.
