Cherokee 4WD V6-173 2.8L VIN W 2-bbl (1985)
Electronic Spark Control Module: Description and Operation
Electronic Spark Control (ESC)
ESC is used in conjunction with electronic spark timing to reduce spark advance during periods of detonation.
A knock or detonation sensor, located in the engine block, signals the ESC controller during periods of detonation. The controller then sends a signal
to the ECM, which reduces spark advance until signals are no longer received from the sensor. Once detonation ceases, the spark control reverts back to
electronic spark timing.
