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Home >> Chevrolet >> 2003 >> Chevy Express H2500 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 4 (Engine Controls - Theory & Operation) >> Computerized Engine Controls >> Input Devices >> Knock Sensor
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Knock Sensor

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The Knock Sensor (KS) produces an AC voltage at all engine speeds and loads. KS is located on top rear of engine. See Fig 1 . The PCM then adjusts the spark timing based on the amplitude and frequency of the KS signal. PCM uses the KS signal to calculate the average voltage. Then PCM assigns a voltage value. PCM checks the knock sensor and related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should stay within the assigned voltage range. A fault in the KS circuit may set a DTC. See A article.

Fig 1: Locating Engine Oil Pressure Sensor, IAC Valve, Ignition Coil, Knock Sensor & TP Sensor
G00028336Courtesy of GENERAL MOTORS CORP.