DTC P0325: Knock Sensor (KS) Circuit Malfunction: Condition

WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when Powertrain Control Module (PCM) does not detect input from KS for 5 seconds with engine running. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:

Knock Sensor (KS) malfunction.
Open or short circuit between KS and PCM.
PCM malfunction.