Knock Sensor
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. To diagnose, perform related diagnostic test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C", "K" & "N" SERIES - FLEX FUEL & GASOLINE article. When a related DTC is not present and the KS system is the suspected cause of a driveability problem, check of KS system. See SYMPTOMS in SYSTEM & COMPONENT TESTING - 4.8L, 5.3L & 6.0L "C", "G", "H", "K" & "N" SERIES- FLEX FUEL & GASOLINE article.