DTC P0325: Knock Sensor Circuit (SOHC): Description
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Knock Sensor (KS) produces an AC voltage at all engine speeds and loads. PCM then adjusts spark timing based on amplitude and frequency of KS signal. PCM uses KS signal to calculate average voltage. Then PCM assigns a voltage value. PCM checks knock sensor and related wiring by comparing actual knock signal to assigned voltage range. A normal KS signal should stay outside assigned voltage range. This DTC will set if KS signal is within assigned voltage range or not present, or if PCM malfunctions in a manner that will not allow proper diagnosis of KS system.