GM 12591625 Sensor Assembly, Knock

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The grown of irregular octane levels in today's gasoline is known to provoke detonation in an engine, known as "spark knock." ESC system provides ability to retard spark timing up to 15 degrees and use optimal spark advance to minimize spark knock for better drive ability and fuel economy. Knock sensor is mounted on the engine block, more specifically on an Electronic Spark Control, ESC; this sensor produces an alternating current voltage signal that it sends to the PCM and the PCM then retards the timing until spark knock is eradicated. The PCM receives an ESC signal; if this signal is somehow cut off then the PCM will constantly retard the EST, the performance will be slow, and a trouble code will be set. To remove the knock sensor follow out the cable from the negative terminal of the automobile with the Theftlock audio system lockout off if there is any. No longer epoxied to the block, remove the knock sensor electrical connector; on later-model 3800 engines, this also removes the heat-shield over the sensor. Although it would have been nice to have been informed that at least some of the screws were designed to be removed without losing their ability to be easily reinserted, remove the sensor from the block by unscrewing it, and installation is of course the reverse of the removal.